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INSTITUTO NACIONAL DE PESQUISAS DA AMAZÔNIA
UNIVERSIDADE FEDERAL DO AMAZONAS
PROGRAMA DE PÓS-GRADUAÇÃO EM BIOLOGIA
TROPICAL E RECURSOS NATURAIS DA AMAZÔNIA
PALINOLOGIA DO NEÓGENO DA BACIA DO ALTO SOLIMÕES,
AMAZÔNIA OCIDENTAL, BRASIL: ASPECTOS SISTEMÁTICOS,
BIOESTRATIGRÁFICOS E PALEOECOLÓGICOS
SILANE APARECIDA FERREIRA DA SILVA
Manaus, Amazonas
FEVEREIRO, 2008
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SILANE APARECIDA FERREIRA DA SILVA
PALINOLOGIA DO NEÓGENO DA BACIA DO ALTO SOLIMÕES,
AMAZÔNIA OCIDENTAL, BRASIL: ASPECTOS SISTEMÁTICOS,
BIOESTRATIGRÁFICOS E PALEOECOLÓGICOS
Dr. MARIA LUCIA ABSY
Dr. CARLOS A. JARAMILLO
Manaus, Amazonas
Fevereiro, 2008
Tese apresentada ao PIPG-BTRN
como parte dos requisitos para
obtenção do título de Doutor em
Ecologia, área de concentração em
Paleoecologia.
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iii
S586 Silva, Silane Aparecida Ferreira da
Palinologia do Neógeno da Bacia do Alto Solimões: Aspectos sistemáticos,
bioestratigráficos e paleoecológicos / Silane Aparecida Ferreira da Silva–
Manaus: INPA/UFAM, 2008.
viii, 182f. il.
Tese (Doutorado) - INPA/UFAM, Manaus, 2008
Orientador: Maria Lúcia Absy
Co-orientador: Carlos A. Jaramillo
Área de concentração: Ecologia.
1. Paleopalinologia 2. Paleoecologia 3. Bioestratigrafia. I. Palinologia do
Neógeno da Bacia do Alto Solimões: Aspectos sistemáticos, bioestratigráficos e
paleoecológicos
CDD 19. Ed. 582.0463
iv
Aos meus pais, irmãos e esposo por representar a
materialização da bondade Divina em minha vida, dedico.
v
AGRADECIMENTOS
Gostaria de agradecer a duas agências federais de apoio ao desenvolvimento
científico: CAPES e CNPq pela concessão de bolsas de estudo tanto no Brasil
como no exterior.
Aos meus orientadores: Profa. Dra. Maria Lúcia Absy pelo acompanhamento
científico durante o mestrado e doutorado; e ao Dr. Carlos Jaramillo, pelos
constantes porquês, e por me fazer compreender que a ciência é feita de olhar as
coisas sempre por outros ângulos.
À PDVSA, PETROBRÁS e ECOPETROL e Carina Hoorn pela disponibilização dos
holótipos e parátipos de muitos grãos identificados durante esse estudo.
À Dra. Cláudia Keller, coordenadora do curso de Ecologia, pela eficiência em agilizar
os processos relacionados a bolsa de estágio no exterior.
Aos Drs. Edgardo Latrubesse, Mario Cozzuol, Jackson da Paz e Fátima Praxedes
Leite, pelas frutíferas discussões sobre geologia, paleontologia e palinologia da
Amazônia.
Ao Dr. Fernando Burgos e Gert Wothje do DNPM, pela facilidade em obtenção e
liberação para estudo no exterior de amostras de sedimentos.
Aos amigos do grupo de Bioestratigrafia do ICP- Instituto Colombiano de Petróleo e
grupo de paleontologia do STRI pela incondicional ajuda e amizade ao longo desses
anos, em especial, a Carolina Vargas, D. Milton Rueda e Dr. Vladimir Torrez.
Pelo apoio logístico do Smithsonian Tropical Research Institute, principalmente pela
eficiência dos amigos da biblioteca na obtenção de trabalhos científicos. Gracias, mi
amigo Angel!
vi
À Sra. Gilda Fernandes, bibliotecária do CPRM-Manaus, pelo profissionalismo
experiente de saber exatamente a localização dos mais antigos e não-utilizados
relatórios internos contidos na biblioteca do CPRM.
À Millerlandy Romero, pela amizade, pelos papers, pelos index cards, pela
confecção dos diagramas polínicos e pelos deliciosos almoços caseiros que me
fizeram sentir em casa durante minha estadia no Panamá.
À MsC. Carlos Francisco, pelas descontraídas discussões em biogeografia e
interpretação de dados moleculares de trabalhos publicados sobre a Amazônia além
da ajuda com o enigmático programa End Note.
À MsC. Paula Sucerquia e Hugo Cauper, pela ajuda com os perfis de poços e alguns
gráficos.
Ao amigo Enrique Moreno pela paciência e disponibilidade em discutir sobre
morfologia e afinidade natural dos grãos que encontrava em meu material.
À Dr. Mauro Toledo e MsC. Alex Correa, pela ajuda nas análises multivariadas, que
infelizmente não entraram nessa tese, mas que farão parte do meu próximo
manuscrito. Ao Mauro também pela correção do Abstract. Qualquer reclamação a
culpa é dele!
À Jean Caminha pelos ensinamentos de velejador, de que: os barcos estão mais
seguros no porto mas não foram feitos pra isso; não há mares tranqüilos e que,
principalmente, não há vento bom para quem não sabe para onde vai.
vii
Resumo
A Amazônia apresenta uma grande diversidade biológica distribuída em uma grande
e heterogênea área geográfica. Para explicar essa alta riqueza muitas hipóteses têm
sido sugeridas. Entretanto, poucos estudos sobre a história geológica e
paleontológica têm sido desenvolvidos com o objetivo de se conhecer aspectos
paleoecológicos da Amazônia em tempos passados. Devido a essa carência em
estudos paleontológicos, encontram-se disponíveis na literatura contraditórias
hipóteses que tentam explicar a evolução do ambiente amazônico bem como
determinados aspectos biogeográficos. Essa tese foi desenvolvida com o objetivo de
levantar aspectos gerais da ecologia e estratigrafia da Amazônia usando-se como
ferramenta a palinologia. Entretanto, foi observado que a nomenclatura palinológica
empregada na literatura, e amplamente usada em trabalhos especializados,
necessitava de uma detalhada revisão. Para esse estudo foram usadas 41 amostras
de sedimentos de duas sondagens realizadas na região do Alto Solimões.
Sistematicamente, foram descritas 112 espécies, cerca de 51 novas espécies, 7
novas combinações foram propostas. Botanicamente, muitos gêneros foram
registrados pela primeira vez na Amazônia, sendo que o uso dessas informações
são importantes para calibração de relógios moleculares. Estratigraficamente, um
novo zoneamento para o Plioceno foi proposto usando-se o método de Associações
unitárias para definir as novas associações. Em relação ao ambiente, pode-se
afirmar que predominou o sistema fluvial altamente dinâmico, sem nenhum registro
indicando ambiente costeiro ou marinho. Desde o Mioceno/Plioceno muitos gêneros
de plantas presentes na Amazônia atualmente já estavam presentes, indicando que
a diversidade atual pode ser resultado de uma longa história de estabilidade
ambiental.
viii
Abstract
The Amazon region harbors high biologic diversity distributed throughout a huge and
heterogeneous area. Many hypotheses try to explain this high diversity present in
Amazonia, as well as in other tropical rainforests. However, few studies about the
geological and paleontological histories have been developed in order to find out
paleoecological patterns of the Amazonian history. In reason of the scarcity of
paleontological studies, some contradictory hypotheses that try to explain the
evolution of the Amazonian environment, as well as some biogeographical aspects,
are available in the literature. The present study was conducted in order to find out
some general aspects of the ecology and stratigraphy of the Amazonia using
Palynology as the main tool. However, it was observed that the palynological
nomenclature used presently needed a review. Forty-one samples from 2 cores
located in the Upper Solimões Basin were analyzed. One hundred twelve species
were systematically described, with 51 being new species, and 7 new combinations
were proposed. Many genera were recorded for the first time in Amazonia. This kind
of information is useful to calibrate molecular clocks. New stratigraphic zones were
proposed for the Pliocene using the Unitary Association method, and the
environment was interpreted as a highly dynamic freshwater system, with no
evidence of coastal or marine influence. Many plant genera that exist today were
present since the Miocene/Pliocene, suggesting that the high modern biodiversity
could be the result of a long history of environmental stability.
9
Sumário
Resumo .................................................................................................. vii
Abstract ..................................................................................................viii
Lista de Tabelas .....................................................................................10
Lista de Figuras ......................................................................................11
1.0 Introdução..............................................................................................13
1.1- Considerações Gerais........................................................................13
1.2- Registros da “Paleoamazônia”...........................................................13
2.0 Objetivos..................................................................................................16
2.1 Objetivo geral.....................................................................................16
2.2 Objetivos específicos .........................................................................16
3.0- Bacia do Solimões..................................................................................17
3.1- Formação Solimões ............................................................................19
3.1.1 - Ambientes de deposição .............................................................24
3.1.2- Palinoestratigrafia da Formação Solimões...................................27
4.0 Material e Métodos ..................................................................................29
4.1 Área de estudo.....................................................................................29
4.1.1- Poço 1AS-27-AM..........................................................................30
4.1.2- Poço 1AS-19-AM..........................................................................32
4.2 Preparação das amostras e contagem dos grãos................................34
4.3 Análise dos dados................................................................................35
4.3.1- Sistemática, taxonomia, afinidades botânica e ecológicas dos
esporomorfos..........................................................................................35
4.3.2- Bioestratigrafia..............................................................................37
10
5.0 Resultados e discussões .........................................................................39
5.1 Sistemática...........................................................................................39
5.2- Bioestratigrafia ....................................................................................40
5.2.1- Bioestratigrafia tradicional ............................................................40
5.2.2- Bioestratigrafia quantitativa ..........................................................49
5.3- Paleoecologia .....................................................................................53
5.3.1- Relação abundância e raridade na composição palinológica.......53
5.3.2- Famílias de angiospermas predominantes...................................57
5.3.3 Primeiros registros de famílias e gêneros na Amazônia................62
5.3.4 Diversidade da Amazônia durante o Neógeno ..............................63
6.0 Conclusões..............................................................................................66
7.0 Referências..............................................................................................67
8.0 Anexos.....................................................................................................72
Lista de Tabelas
Tabela 1: Zonas estabelecidas por Hoorn (1993) com as associações de
espécies. ................................................................................................28
Tabela 2: Zonas palinológicas estabelecidas para Venezuela e Amazônia. .44
Tabela 3: Tabela mostrando a composição de cada UA. Em amarelo está a
associação típica da UA2. Em azul a espécie encontrada somente na
UA1. Na seção intermediária estão as espécies das UA1/2. A primeira
coluna corresponde aos números contidos nos gráficos orientados e não
orientados...............................................................................................51
Tabela 4: Afinidade botânica e hábito de alguns esporos que apresentaram
abundância na associação. ....................................................................55
11
Tabela 5: Tabela com alguns tipos polínicos encontrados e suas informações
botânicas. ...............................................................................................56
Tabela 6: Afinidade botânica de alguns fósseis.............................................61
Tabela 7: Informações botânicas das famílias/Gêneros registrados pela
primeira vez na Amazônia. .....................................................................62
Lista de Figuras
Figura 1: Localização aproximada das Bacias do Estado do Amazonas.......18
Figura 2: Delimitação das sub-bacias na Bacia do Solimões. Modificado de
Silva, 1987..............................................................................................18
Figura 3: Seção de referência da Fm Solimões. Extraída e modificada de
Caputo et al. (1971)................................................................................21
Figura 4: Seção-tipo da Fm. Solimões. Extraído e modificado de Eiras et al.
(1994). ....................................................................................................22
Figura 5: Seção-referência da Fm. Solimões. Extraída e modificada de Eiras
et al. (1994). ...........................................................................................23
Figura 6: Modelo de depósito fluvial com fácies de planície de inundação,
típicos da Fm Solimões. .........................................................................27
Figura 7: Mapa de localização onde os poços foram perfurados...................30
Figura 8: Perfil estratigráfico do poço 1AS-27-AM juntamente com perfis de
raios-gama e resistividade......................................................................31
Figura 9: Perfil estratigráfico do poço 1AS-19-AM juntamente com perfis de
raios-gama e resistividade......................................................................33
12
Figura 10: Correlação estratigráfica usando a bioestratigrafia tradicional da
região......................................................................................................41
Figura 11: Carta de distribuição do 1AS-27-AM ............................................47
Figura 12: Carta de distribuição do 1AS-19-AM. ...........................................48
Figura 13: Correlações estratigráficas usando-se o método de Associação
Unitária ...................................................................................................49
Figura 14: A) gráfico não Orientado, onde os números correspondem as
espécies (vértices) e as setas em azul (arestas) correspondem a relação
de co -ocorrência entre as espécies, B) gráfico Orientado, onde os
números correspondem as espécies (vértices) e as setas em vermelho
(arcos) correspondem a relação de superposição entre as espécies.....51
Figura 15: Gráfico de freqüência (%) de esporos, famílias de angiospermas e
gimnospermas encontradas no Poço 1AS-27-AM..................................54
Figura 16: Gráfico de freqüência de esporos, famílias de angiospermas e
gimnospermas encontradas no Poço 1AS-19-AM..................................54
Figura 17: Diagrama palinológico com abundância de esporomorfos no poço
1AS-27-AM.............................................................................................59
Figura 18: Diagrama palinológico com abundância de esporomorfos a nível
de família/gênero no poço 1AS-19-AM...................................................60
13
1.0 Introdução
1.1- Considerações Gerais
Existem duas maneiras de estudar o passado de florestas tropicais.
Uma por meio de análise molecular e a outra por meio de paleontologia,
sendo a primeira mais moderna, mas dependente da segunda. Isso se deve
ao fato de que a análise molecular usa dados obtidos pela paleontologia tais
como, estado de caracteres morfológicos e registro de primeiro aparecimento
de táxons, para datar tempo de divergência entre espécies (Smith 1998) e
calibrar relógio molecular. A paleontologia também depende de outras
ciências tais como a geologia, sistemática e ecologia.
Aqui, forneceremos fornecer dados sobre a história da floresta
Amazônica durante o Neógeno. Algumas famílias/gêneros serão pela
primeira vez descritas no registro fossilífero no Norte da América do Sul.
Algumas inferências sobre a paleovegetação serão abordadas, desde
famílias predominantes e como esses registros podem ser interpretados.
Serão discutidos também alguns aspectos de zoneamentos
bioestratigráficos atualmente aceitos e sugerida uma nova interpretação
estratigráfica usando-se um método de Bioestratigrafia Quantitativa
denominado Associações Unitárias e o compararemos com o zoneamento
tradicional utilizado na região
1.2- Registros da “Paleoamazônia”
Acreditava-se que a diversidade biológica da Amazônia estava
relacionada à adaptação de espécies a novos ambientes devido a mudanças
climáticas ocorridas no Pleistoceno. Atualmente, alguns aspectos dessa
teoria denominada “teoria dos refúgios” tem sido testada principalmente por
14
análises moleculares de plantas e animais (Schneider et al. 1999; Aleixo
2004).
A maioria desses trabalhos apóia a idéia de que a diversificação da
Amazônia ocorreu antes das flutuações climáticas do Pleistoceno e, eventos
anteriores a esse intervalo de tempo deveriam ter facilitado a especiação e
acumulação de espécies. Eventos ocorridos provavelmente, no Mioceno ou
Plioceno (Pennington et al. 2004).
No Mioceno, a região Amazônica sofria mudanças ambientais
ocasionadas principalmente pelo soerguimento da Cordilheira Oriental
Andina, o que propiciou a mudança da direção de drenagem dos rios
amazônicos no sentido Atlântico e que, possivelmente, gerou o Rio
Amazonas com as mesmas características que as atuais Hoorn et al. 1995.
Os Andes também foram responsáveis pela formação do Rio Orinoco na
Venezuela além de funcionar como barreira e manter o clima estável na
Amazônia pelos últimos milhões de anos (Kaandorp et al. 2005).
De forma geral, esses resultados fazem parte de uma ampla pesquisa
realizada por holandeses que usaram dados de sedimentologia e
paleontologia na Amazônia, Venezuela e Colômbia.
Vale ressaltar que a Amazônia sul ocidental brasileira está coberta por
rochas terciárias pertencentes à Formação Solimões, que apresenta níveis
ricos em conteúdo fossilífero de invertebrados, vertebrados e restos vegetais
que afloram principalmente no Estado do Acre. Os fósseis coletados estão
atualmente depositados na coleção existente na Universidade Federal do
Acre que conta com mais de 5.000 mil exemplares obtidos ao longo dos rios
Acre, Purus e Juruá.
A maioria das informações extraídas desses fósseis está descrita
principalmente, em periódicos nacionais, o que limita o conhecimento e a
utilização desses registros em outros estudos internacionais.
Esses fósseis, principalmente de vertebrados, são do Mioceno
Superior (aproximadamente 9 a 6 milhões de anos passados) e carecem de
informações mais detalhadas, tais como: 1) controle estratigráfico dos níveis
em que os fósseis foram extraídos; 2) datações absolutas ou zoneamentos
bioestratigráficos confiáveis e 3) informações geológicas e paleontológicas
15
integradas que possam permitir um quadro geral sobre a paleoecologia da
Amazônia.
De acordo com dados paleontológicos, o paleoambiente durante o
Neógeno foi complexo, com grandes corpos de água doce. altamente
produtivos entre áreas abertas e de floresta densa. Um fato marcante é a
grande diversidade encontrada, somente em crocodilianos são 16 espécies
registradas, fato que não ocorre atualmente em nenhuma parte do mundo
(Cozzuol 2006). Ainda há discussões sobre a diversidade encontrada no Acre
ocorrer devido a diferenças temporais ou ambientais (Cozzuol, com. pess).
Nesse sentido, a palinologia se faz importante na determinação tanto
de fatores estratigráficos como ambientais. O fator estratigráfico pode ser
definido, em parte, pela presença de marcadores bioestratigráficos do
Neógeno definidos para a região Norte da América do Sul por (Germeraad et
al. 1968; Lorente 1986; Muller et al. 1987 e Hoorn 1993) como
Crassoretitriletes vanraadshoovenii, Grimsdalea magnaclavata e
Echitricolporites spinosus ou, como proposto neste trabalho, por um
refinamento do zoneamento mais específico com métodos de Bioestratigrafia
quantitativa. O fator ambiental é determinado pela inferência pela
caracterização da vegetação dominante que se dá por meio da afinidade
botânica e ecológica das espécies observadas em amostras de rochas do
Neógeno da Amazônia. Integrados, estes dados podem permitir uma
completa interpretação biológica da Amazônia ao longo do tempo.
16
2.0 Objetivos
2.1 Objetivo geral
A presente pesquisa teve como objetivo principal ampliar o
conhecimento dos palinomorfos do Terciário Superior encontrados na
Formação Solimões, levando-se em consideração os aspectos sistemáticos,
bioestratigráficos e paleoecológicos afim de evidenciar características
temporais e ambientais da Amazônia durante o Neógeno.
2.2 Objetivos específicos
1) Descrever grãos novos, seguindo descrições morfológicas empregadas em
esporomorfos do Paleoceno e Eoceno da Colômbia a fim de padronizar as
descrições feitas em áreas tropicais.
2) Revisar a nomenclatura empregada em esporomorfos já descritos,
aplicando-se os conceitos sugeridos pelo Código Internacional de
Nomenclatura Botânica.
3) Encontrar padrões no registro palinológico que possam colaborar para
uma nova interpretação e uso em bioestratigrafia, contribuindo assim para a
criação de um arcabouço cronológico de primeiro aparecimento de espécies
que possam ser aplicados bioestratigraficamente em outras áreas na
Amazônia.
4) Encontrar padrões na composição palinoflorística durante o Mioceno e
Plioceno da Amazônia além de obter dados sobre a origem da diversidade
amazônica durante esse intervalo.
17
3.0- Bacia do Solimões
O Estado do Amazonas possui três grandes Bacias: Bacia do
Amazonas, Bacia do Solimões e Bacia do Acre e que, são delimitadas pela
presença de arcos estruturais.
A Bacia Paleozóica do Solimões possui uma área aproximada de
600.000 km
2
, entre os paralelos 2º e 8º S e meridianos 62 º e 72º W, limita-se
ao leste pelo arco do Purus, que a separa da Bacia do Amazonas, e ao oeste
pelo arco de Iquitos, que a separa da bacia do Acre (Silva 1987). Os limites
norte e sul são delimitados pelos Escudo das Guianas e Escudo Brasileiro,
respectivamente (Figura 1).
A localização, extensão e tempo em que o arco de Iquitos esteve
exposto têm sido controversa e discutida na literatura (Caputo 1984; Roddaz
et al. 2005).
A bacia do Solimões possui duas sub-bacias: Juruá e Jandiatuba,
sendo as duas separadas pelo arco de Carauari (Figura 2). A sub-bacia de
Juruá está localizada ao leste do arco de Carauari e está sendo muito
estudada devido a exploração de gás pela Petrobrás desde 1997. A Sub-
Bacia Jandiatuba ao contrário da Juruá, é pouco conhecida devido a
presença de reservas florestais e terras indígenas (Eiras et al. 1994). No
entanto, modelos estruturais do Paleozóico foram desenvolvidos para essa
sub-bacia (Silva 1987).
18
Figura 1: Localização aproximada das Bacias do Estado do Amazonas.
.
Figura 2: Delimitação das sub-bacias na Bacia do Solimões. Modificado
de Silva, 1987
19
A carta estratigráfica da bacia do Solimões adotada pela Petrobrás
(Eiras et al. 1994) divide a Bacia do Solimões em nove unidades geológicas
desde o Pré-Cambriano: sete delas pertencentes ao Paleozóico, uma ao
Mesozóico e a última ao Cenozóico.
3.1- Formação Solimões
A Formação Solimões, unidade geológica que representa o Cenozóico
da Bacia do Solimões, está presente também nas bacias do Amazonas e
Acre. Pouco consenso existe sobre a sua extensão, ambiente e intervalo de
idade dos sedimentos pertencentes a essa unidade (Westaway 2006).
O termo Solimões foi designado por Moraes-Rego (1930) que
denominou como Série Solimões, as argilas e areias pardas, castanhas e
azuis presentes em afloramentos dos rios Acre, Javari, Purus e Solimões
(apud RADAMBRASIL 1977). Esse termo foi discutido e revalidado por
Caputo et al. (1971).
Trabalhos têm tratado a Formação Solimões como correlata de Pebas
(Hoorn, 1993; Wesselingh et al. 2001). Essa idéia acabou por se difundir na
tentativa de classificação estratigráfica da Fm. Solimões, por exemplo,
Almeida (1974) propôs a elevação da Fm. Solimões à categoria de grupo,
mantendo a denominação Fm. Pebas para representar uma unidade
intermediária do grupo Solimões. Entretanto, Caputo et al. (1971) enfatizam
que o termo Pebas somente se refere a algumas camadas fossilíferas
aflorantes no Peru e que, esse termo, deveria ser evitado como correlato de
Fm. Solimões pois “Pebas” não possui uma descrição formal. Aqui, será
utilizada a denominação Formação Solimões por ser uma unidade
formalmente descrita.
Algumas seções–tipos e de referências distintas (Caputo, et al. 1971;
Maia et al. 1977; Eiras et al. 1994) estão descritas para a Formação Solimões
e, aqui foram ilustradas duas delas.
Caputo et al. (1971), afirmam que a localidade-tipo da Formação
Solimões se estende ao longo do Rio Solimões, na Amazônia Ocidental
brasileira. A seção de referência corresponde aos primeiros 570 metros de
20
profundidade do poço 2-RCST-1-AM no Rio Curuçá, cuja localização está
próxima a fronteira Brasil-Peru (Figura 3).
Maia et al. (1977) concorda com a seção-tipo sugerida feita por Caputo
et al. (1971) e delimitam geograficamente a seção-tipo entre as cidades de
São Paulo de Olivença e Tabatinga, no Estado do Amazonas.
A ausência de uma seção-tipo mais específica faz com que Eiras et al.
(1994) apresentem um perfil como seção-tipo da unidade, sendo o poço 2-
RJ-1-AM (Figura 4) e como seção-referência, o perfil 1-BV-1-AM (Figura 5).
O contato inferior da Fm. Solimões com a Formação Alter do Chão é
marcado pela redução dos raios gama devido à passagem de argila para
areia (como mostrado nos perfis abaixo), e seu contato superior é feito com
depósitos de praias e planícies de inundação (Caputo et al. 1971). Em
contraposição, Maia et al. (1977) sugerem uma nova unidade denominada
Formação Içá para esse depósito. A Fm. Içá composta de arenitos amarelo-
avermelhados, fino a conglomerático e friável se sobrepõe a Formação
Solimões.
21
Figura 3: Seção de referência da Fm Solimões. Extraída e modificada de
Caputo et al. (1971).
22
Figura 4: Seção-tipo da Fm. Solimões. Extraído e modificado de Eiras et
al. 1994
23
Figura 5: Seção-referência da Fm. Solimões. Extraída e modificada de
Eiras et al. (1994).
24
Ainda de acordo com Caputo et al. (1971), a Formação Solimões
consiste litologicamente de: 1) argilitos vermelhos, cinzas e variegadas,
sílticos, laminados, com abundantes camadas contendo gipsita em níveis
marrons ou cinza-esverdeado; 2) arenitos variando de finos a médios, cinza-
esverdeado, branco e marrom-avermelhado, friáveis, com laminação
cruzada; 3) conglomerados intraformacionais, com seixos compostos de
argilito e siltito e; 4) camadas de linhito de 2 a 10 metros nos primeiros 300 m
de profundidade.
Em relação à idade em que os sedimentos foram depositados, Caputo
et al. (1971) sugerem Paleoceno a Pleistoceno, sendo que trabalhos
bioestratigráficos realizados por Daemon e Contreiras (1971) suportavam
essa idade. Posteriormente, por meio de associações palinológicas sugeriu
idade mais recente (mio/pliocênica) para as seções estudadas. Essa idade
proposta por Cruz (1986) foi confirmada dados de vertebrados. A presença
de vertebrados fósseis no Estado do Acre permitiu refinar a idade da
Formação Solimões no intervalo em que essa unidade aflora, sugerindo o
intervalo Mioceno Superior.
Latrubesse et al. (1997) registram a presença de roedores:
Potamarchus, Neopiblema horridula, Phoberomys burmeisteri e do Toxodonte
Trigodon, que indicam idade Mioceno Superior/Plioceno
(Huayquerense/Montehermosane). A idade de 9-6.5 Ma poderia ser sugerida
baseando-se em SALMA (Huayquerian/Mesopotamian South America land
Mammal) com grande similaridade faunística encontrada na Argentina. No
entanto, Cozzuol (2006) re-avaliando a idade da fauna do Acre encontrou
somente indicativos de Mioceno Superior (Huayquerian South America land
Mammal), com a ausência de registros mais recentes.
3.1.1 - Ambientes de deposição
De forma sucinta, Roddaz et al. (2005) sumarizam 5 contraditórias
hipóteses que tentam explicar o tipo de ambiente predominante durante a
deposição de sedimentos da Formação Solimões. As duas primeiras
propõem idade mais recente do que a aceita atualmente na literatura, e são
as que afirmam que:
25
1) Os sedimentos foram depositados devido a uma inundação
pleistocena vinda do Lago Tititaca (Campbell e Frailey 1984).
2) Eles apresentam uma deposição típica de delta de um grande lago
pleistoceno denominado lago Amazonas (Frailey et al. 1988)
As outras três propõem idade miocena e pliocena para a origem da
Formação Solimões.
3) Apresentam sedimentos do Mioceno/Plioceno que foram depositados
em um sistema de leque aluvial (Latrubesse et al. 1997).
4) São depositados em um sistema fluvial Hoorn 1993) com episódios de
incursões marinhas. Nuttall 1990 e Hoorn et al. (1995) sugeriram ainda, que
incursões marinhas atingiram o Noroeste da Amazônia brasileira oriundas do
Mar Caribenho.
5) Dados sedimentológicos indicam que houve ambientes de maré
durante o Mioceno Superior (Rasanen et al. 1995).
E, acrescentando mais uma importante hipótese, não citada no trabalho
de Roddaz et al. (2005).
6) A Formação Solimões foi depositada em um sistema de um grande
lago que existiu desde o Mioceno Inferior até o início do Mioceno Superior
(Wesselingh e Salo 2006).
Vonhof et al. (1998) e Wesselingh et al. (2002) baseados em
composição de moluscos e isótopos sugeriram que a Amazônia durante o
Mioceno Médio Superior apresentava mais características de ambiente
lacustre do que de ambiente de planície fluvial e que, portanto, foi coberta por
um lago predominantemente de água doce, que atingiu o Norte do Brasil,
Colômbia e Peru. Eles sugeriram ainda, que o denominado então “Lago
Pebas” teve características semelhantes ao lago de Maracaibo, devido a
presença de organismos adaptados à água salobra. Eles acrescentam que,
episódios de incursão marinha poderiam ter passado pelos Los Llanos.
Dados palinológicos indicam que durante o Mioceno, a Amazônia foi
coberta por uma extensa área inundada com abundância de esporos e
palmeiras. As bacias do Solimões e Amazonas apresentavam baixa
sinuosidade e sistema de drenagem em direção nordeste (Hoorn et al. 1995).
26
A abundância de grãos de Rhizophora (Zonocostites ramonae) e
palinomorfos marinhos (dinoflagelados e foraminíferos) sugere incursões
marinhas em dois intervalos: uma no Mioceno Inferior (zonas de
Verrutricolporites e Psiladiporites-Crototricolpites) e outra no Mioceno
Médio/Superior (Zonas de Crasoretitriletes e Grimsdalea) (Hoorn 1994a).
Os registros de incursões marinhas foram corroborados por dados
moleculares que afirmam que a presença atual de animais descendentes de
linhagens marinhas na Amazônia, tais como: peixes, peixes-boi, botos e
arraias devem-se a eventos marinhos ocorridos durante o Mioceno Inferior
(Lovejoy et al. 1998).
No Mioceno Médio/Superior, índices de isótopos de estrôncio
confirmam uma incursão marinha na zona de Grimsdalea invadindo um
ambiente flúvio-lacustre (Vonhof et al. 1998). Durante esse período,
ocorreram mudanças no padrão de drenagem dos rios amazônicos, que
passaram a drenar no sentindo atual, com direção de transporte ao Oceano
Atlântico.
Para o Mioceno Superior existe muita controvérsia em relação a
ambiente deposicional e dados palinológicos são escassos para testar os
ambientes propostos.
Um dos trabalhos mais debatidos é o que propõe um imenso mar
intracontinental (hipótese 5) que ligou o caribe com o Atlântico Sul (Rasanen
et al. 1995). Esse trabalho descreve que durante o Mioceno Superior, a
Amazônia bem como parte do continente sul-americano foi coberto por um
mar epicontinental. Essa hipótese foi usada para explicar padrões na
distribuição de vegetação na América do Sul (Webb 1995).
Apesar dados palinológicos assim como fósseis de vertebrados
rejeitarem ambiente marinho/costeiro e apontarem para um ambiente de
água doce com pântanos, floresta aberta e com matas de galerias (Cozzuol,
2006; Latrubesse et al. 2007/Anexo2), recentes estudos sedimentológicos
também apóiam a presença de marés (Hovikoski et al. 2007).
RADAMBRASIL (1977) afirma que todos os afloramentos da Fm.
Solimões visitados pelo projeto apontam para um ambiente fluvial com
características de ambientes de planícies de inundação (Figura 6).
27
Figura 6: Modelo de depósito fluvial com fácies de planície de
inundação, típicos da Fm Solimões RADAMBRASIL 1977.
3.1.2- Palinoestratigrafia da Formação Solimões
O primeiro arcabouço palinoestratigráfico para o Neógeno
desenvolvido em áreas tropicais foi descrito por Germeraad et al. (1968) para
África e América do Sul. Esse arcabouço foi posteriormente melhorado Regali
et al. 1974; Lorente 1986; Muller et al. 1987) e parcialmente calibrado com o
uso de foraminíferos.
A aplicação dessas zonas palinoestratigráficas na Amazônia ocorreu
poucos anos depois (Daemon e Contreiras, 1971), no entanto, somente na
década de 90 foi amplamente divulgada e usada em outros estudos
paleontológicos (Hoorn 1993, 1994).
No caso do Mioceno e Plioceno, existem poucos e inexatos estudos no
que se refere a idade estabelecida a eventos de primeiro aparecimento e
extinção de espécies utilizadas bioestratigraficamente, devido a incertezas na
correlação com zonas de planctônicos (Germeraad et al. 1968, pg. 247).
Somente na década de 90, um trabalho minucioso de bioestratigrafia
tradicional foi realizado em dois testemunhos de sondagem perfurados na
região do Alto Solimões, permitindo a elaboração de novas biozonas locais
usando-se associações Hoorn 1993) que, na prática tem sido usada como
marcadores cronoestratigráficos (Wesselingh et al. 2002).
28
Hoorn (1993) estabeleceu para a área, cinco zonas palinológicas do
Mioceno Inferior até o intervalo do Mioceno Médio para o Superior. De modo
geral, as zonas puderam ser definidas pela presença/ausência e/ou
abundância/escassez de espécies (Tabela 1).
Tabela 1: Zonas estabelecidas por Hoorn (1993) com as associações de
espécies.
Idade
Zonas
Associações /limites das zonas
Mioceno
Médio/
Superior
E: Grimsdalea
Topo: indefinido
Base: primeiro aparecimento de G.
magnaclavata
Mioceno
Médio
D: Crassoretitriletes
Topo: antes do primeiro aparecimento de G.
magnaclavata
Base: primeiro aparecimento de C.
vanraadshoovenii.
C: Psiladiporites-
Crototricolpites
Topo: antes do primeiro aparecimento de
C.vanraadshoovenii.
Base: Primeiro aparecimento de P. minimus,
C. annemariae, Proxapertites tertiaria ou
Retimonocolpites absyae.
B: Retitricolporites
Topo: Abundância de R. guianensis
Base: : decréscimo de V. rotundiporus
Mioceno
Inferior
A: Verrutricolporites
Topo: decréscimo de V. rotundiporus
Base: Abundância de V. rotundiporus
De acordo com Hoorn (1993) as zonas acima descritas foram
modificadas a partir de zonas estabelecidas anteriormente por Lorente (1986)
na Venezuela. As idades das zonas palinológicas definidas para a três Bacias
na Venezuela foram calibradas usando-se dados de foraminíferos e
nanofósseis calcáreos (Lorente 1986). No entanto, algumas espécies
utilizadas como marcadores bioestratigráficos necessitam ser revisadas pelo
fato do ambiente estar controlando sua a presença. Por outro lado, alguns
marcadores usados nessa abordagem têm seu primeiro aparecimento mais
antigo do que se afirmava.
Leite (2007) registrou zonas mais recentes do que as proposta por
Hoorn (1993). Em suas amostras da sondagem 1AS-33-AM foi registrada a
presença de Psilatricolporites caribbiensis marcando portanto, rochas
pliocenas na área.
29
4.0 Material e Métodos
4.1 Área de estudo
Na década de 70 dois grandes projetos foram financiados pelo
governo federal na região do Alto Solimões e executados pela CPRM e
DNPM, favorecendo assim, o conhecimento geral do ambiente amazônico
que até então, havia sido estudado por pequenos grupos de pesquisa
atuando em áreas pontuais.
O primeiro projeto denominado “Projeto carvão do Alto Solimões” tinha
como finalidade explorar áreas com potencial para produção e exploração de
carvão. Com esse projeto foi possível a perfuração de alguns poços de
sondagem cobrindo uma extensa área no Alto Solimões, atingindo a Fm.
Solimões, Fm. Içá e Fm. Alter do chão. Esses testemunhos de sondagens
estão atualmente depositados na litoteca do DNPM-Manaus.
Simultaneamente, foi desenvolvido o segundo projeto denominado
como RADAMBRASIL- Programa de integração Nacional, que tinha como
objetivo o levantamento de recursos naturais na região. Nesse projeto foram
realizados levantamentos sobre geologia, geomorfologia, pedologia e
inventários florísticos em toda Amazônia.
Informações e material de sondagem desses dois projetos foram
utilizados para a elaboração dessa tese.
Dois poços, 1AS-27-AM (folha SB 19 XA) e 1AS-19-AM (folha SB 19
VB) foram escolhidos (figura 7), levando-se em consideração dois fatores:
posição mais central dentro da Bacia e estado de conservação desse
material na litoteca.
Na folha SB 19 Juruá, onde os poços estão localizados, a Formação
Solimões apresenta duas formas de relevo, o planalto rebaixado da
Amazônia e depressão do Rio Acre-Javari. De acordo com o RADAMBRASIL
(1977), essa área é composta por contrastes morfológicos e texturais em que
os relevos podem estar associados com tipos da litologia da Fm Solimões: 1)
relevo colinoso mais baixo associados com sedimentos síltico-argiloso de
30
depósitos de transbordamento; e 2) relevo colinoso mais elevado associados
com depósitos arenosos típicos de barras em pontal. Esses dois ambientes
estão relacionados com ciclos fluviais.
Figura 7: Mapa de localização onde os poços foram perfurados.
4.1.1- Poço 1AS-27-AM
De acordo com o RADAMBRASIL (1977), a área em que a sondagem
foi realizada é caracterizada geologicamente por arenitos terciários que se
apresentam em forma de: 1) interflúvios tabulares, 2) relevos dissecados
(cristas ou colinas) e 3) superfície ondulada e faixas com áreas de
acumulação de sedimentos recentes próximo aos rios (terraços, áreas
inundadas e inundáveis).
A área de sedimentos terciários é dominada por vegetação de
Floresta Densa com dominância de árvores com porte de 30-40 m e por
florestas de palmeiras. Em terrenos Quaternários, a Floresta densa somente
31
domina os terraços sendo que nas planícies inundáveis e inundadas há
dominância de palmeiras.
O poço 1AS-27-AM, com coordenadas de 04 17’S e 67 5’W, tem 402,5
metros de profundidade, localizado próximo a Tamanduá, no Rio Jutaí. De
acordo com o perfil estratigráfico, ele atinge três Formações geológicas: Içá,
Solimões e Ramon. O perfil litológico e geofísico dessa sondagem com a
localização das amostras encontra-se na figura 8.
Figura 8: Perfil estratigráfico do poço 1AS-27-AM juntamente com perfis
de raios-gama e resistividade.
32
4.1.2- Poço 1AS-19-AM
Atualmente, a área em que o poço 1AS-19-AM foi perfurado é coberta
principalmente por arenitos terciários (interflúvios tabulares, relevos
dissecados em cristas e colinas e superfície ondulada) seguido de depósitos
Quaternários (terraços e planícies aluviais)(Figura 7). O inventário florístico
feito pelo RADAMBRASIL (1977)- folha SB 19 VB, mostra que a área é
dominada por florestas de palmeiras que se estendem sobre áreas de
depósitos Quaternários e Terciários seguida de áreas com florestas
emergentes.
O poço 1AS-19-AM (04 33’S/69 10’W) é mais raso que o 1AS-27-AM
tendo somente 255,7 metros de profundidade. Essa sondagem foi feita
próximo ao igarapé Boa vista e Rio Jandiatuba, no Município de São Paulo
de Olivença, Amazonas. No perfil estratigráfico realizado pela CPRM está
descrito que toda a seção pertence ao Terciário e somente os 3 primeiros
metros de areia pertencem ao Holoceno. Como pode se observar abaixo,
toda a seqüência está composta de argila intercalada com níveis de areias.
No intervalo de 100 a 220 metros de profundidade estão descritos alguns
níveis fossilíferos, calcíferos e carbonosos, com material orgânico bem
preservado (Figura 9).
33
Figura 9: Perfil estratigráfico do poço 1AS-19-AM juntamente com perfis
de raios-gama e resistividade.
34
4.2 Preparação das amostras e contagem dos grãos
No total 41 amostras foram estudadas nos dois poços. Essas amostras
foram preparadas no Instituto Colombiano del Petroleo-ICP seguindo a
metodologia descrita em Traverse (1988) e detalhadamente descrita em
vários trabalhos (Antonioli 2001; Leite 2007). As amostras foram
selecionadas de acordo com a cor do sedimento (materiais mais escuros são
mais promissores) e de granulometria média (material argiloso) (Antonioli
2001).
A metodologia consiste no ataque com ácido clorídrico e fluorídrico de
modo que não restem mais resíduos de materiais inorgânicos como:
carbonatos, silicatos e matéria orgânica carbonizada. Em linhas gerais o
tratamento empregado foi:
1) Maceração das amostras, ataque com HCl a 32% por 2 horas para
eliminação de carbonatos.
2) ataque com HF a 40% por 18 horas para eliminação de silicatos,
para retirada do produto resultante (fluorsilicato) utilizou-se HCl a 10%.
3) O material foi lavado, em todas as etapas, com água destilada por
três vezes para neutralizar a ação dos ácidos.
4) Após a acidificação das amostras, peneirou-se em malha de 200µm
visando-se eliminar a parte inorgânica grosseira e assim concentrar os
palinomorfos na fração restante.
5) Nos casos de amostras com material orgânico carbonizado utilizou-
se uma solução composta por HNO
3
e KCLO
3
de 15 min. a 1 hora
dependendo do grau de oxidação da amostra. O tempo de duração é
determinado pela mudança da cor de preto para castanho (Antonioli 1998). A
solução usada para oxidar parte da matéria orgânica foi utilizada em uma
parte de cada amostra, sendo também utilizada essa fração para a contagem
dos grãos. Estruturas morfológicas dos grãos são mais facilmente
35
distinguíveis quando as amostras são oxidadas. Entretanto, grãos com exina
muito sensível podem ser perdidos durante essa etapa do processo químico.
Por isso, preferiu-se usar duas lamínulas na mesma lâmina, uma com
material oxidado e a outra com material não oxidado.
6) Após a lavagem com HCl a 10% e lavagem com água destilada
preparando a amostra para a separação de constituintes pela diferença da
densidade entre eles. Esse método consiste na separação por flotação
utilizando ZnCL
2
de densidade entre 1,95 a 2,0 que é então, centrifugado por
20 minutos em velocidade de 1500 a 2000 rpm. A parte sobrenadante é
retirada e novamente submetida a centrifugação com Cloreto de zinco por 20
min. a 1500-2000 rpm.
7) O material sobrenadante é colocado em outro tubo com álcool
comercial e centrifugado por 5 min. a 1500-2000 rpm. O resíduo foi lavado
com água destilada por 1 min. e em seguida centrifugado com HCl a 10% por
1 min. em velocidade de 1500-2000 rpm.
8) Finalmente, as amostras foram lavadas por três vezes com água
destilada. No entanto, havendo permanecido material húmico nas amostras .
Esta foi aquecida por 15 min. com KOH. Após essas etapas o resíduo foi
então peneirado com malha de 10 µm e a fração retida na peneira foi
transferida para tubos de 10 ml para a preparação de lâminas palinológicas.
9) Uma lâmina de cada amostra foi confeccionada e analisada em
Microscópio Zeiss, Eclipse 200 em objetivas de 20x e 100x. Quando possível,
300 grãos de pólen e esporos foram contados em cada lâmina, além de
esporos de fungos e algas.
4.3 Análise dos dados
4.3.1- Sistemática, taxonomia, afinidades botânica e ecológicas dos
esporomorfos.
Os trabalhos de Van der Hammen (1956a) foram pioneiros na
Palinologia tropical. Entretanto, alguns gêneros fósseis propostos nesses
36
trabalhos possuem espécies recentes como espécie-tipo, o que vai de
encontro com as normas do Código Internacional de Nomenclatura Botânica-
ICBN (sigla em inglês), o que os tornam gêneros inválidos.
Esses gêneros foram revisados e substituídos por gêneros válidos
fazendo-se novas combinações, conforme sugestões (Jansonius e Hills 1976;
Jansonius 1978; Burger 1994). Na a revisão realizada nesse trabalho,foram
utilizadas as descrições genéricas feitas em Jansonius e Hills (1976) e
suplementos.
Novas espécies foram detalhadamente descritas, utilizando-se a
nomenclatura de morfologia polínica sugerida em Punt et al. (2007) e foi
seguido como modelo as descrições de Jaramillo e Dilcher (2001).
Para esporos um índice (TLI-para triletes e MLI-para monoletes) foi
usado para indicar a relativa proporção do radius x comprimento do grão,
para esporos triletes: TLI (index trilete) = comprimento do radius/ (diâmetro do esporo/2)
e para monoletes: MLI (index monolete) = comprimento da laesura/ comprimento do
esporo.
Na descrição do pólen, dois índices foram usados CPi e CPe para
indicar a proporção do colpi X dimensões do grão. Pólen em vista equatorial:
Cpi (comprimento do colpi/diâmetro polar) e pólen em vista polar: CPe (comprimento do
colpi/ diâmetro equatorial).
No mínimo duas medidas foram tiradas para expressar a dimensões dos
grãos. Os tamanhos extremos (máximo e mínimo) e a média de tamanho
entre parênteses, o desvio padrão, as proporções de diâmetro polar x
diâmetro equatorial e o número de grãos que foram medidos (n). O
comprimento do diâmetro equatorial e largura foram medidas em vista
equatorial dos grãos. Os diâmetros polar e equatorial foram medidos em vista
polar.
Para a correta identificação dos grãos de pólen e esporos e
comparações, vários holótipos descritos (Regali et al. 1974, Lorente 1986,
Hoorn 1993, Hoorn 1994b e Jaramillo e Dilcher 2001) foram detalhadamente
analisados.
37
As afinidades botânicas dos grãos foram estabelecidas e comparadas
com grãos atuais usando-se tanto a literatura especializada (Absy, 1979;
Hooghiemstra 1984; Roubik e Moreno 1991) como a coleção de palinologia
do INPA e coleção do Amazonas do STRI.
Informações botânicas como: hábitos, estratégia reprodutiva das
famílias e gêneros além de dados interpretação ambiental dessas famílias
foram obtidas em (Absy 1979; Poumot 1989, Bush 1995Ribeiro et al. 1999).
4.3.2- Bioestratigrafia
No presente estudo, foram utilizadas duas formas de se analisar dados
bioestratigráficos:
1) A bioestratigrafia tradicional, que leva em consideração, a
presença/ausência ou abundância de marcadores bioestratigráficos para
determinar idade aos sedimentos. A interpretação dos dados foi feita de
acordo com o zoneamento estabelecido para o norte da América do Sul
(Germeraad et al. 1968; Regali et al. 1974; Lorente, 1986; Muller et al. 1987;
Hoorn, 1993).
2) A bioestratigrafia quantitativa, sendo escolhido o método de
Associações Unitárias (Unitary association- UA) devido à natureza das
seções disponíveis para esse estudo. O método de associações unitárias foi
desenvolvido por Guex (1991) para a correlação bioestratigráfica de
afloramentos pertencentes a diferentes localidades. Esse método utiliza
matrizes e conceitos em teoria de gráficos para estabelecer relações de co-
existência e superposição entre as espécies. Desse modo, o método constrói
uma escala cronológica de eventos, descrevendo uma seqüência de
intervalos usando-se associações denominadas UA. Com a utilização desse
método será possível estabelecer novas zonas com novas associações de
espécies além de permitir a correlação entre os dois poços.
Para essa análise, 41 espécies foram selecionadas (tabela 3)
conforme sugestões feitas por Guex (1991), tais como: eliminar espécies
endêmicas, ou seja presentes em somente uma seção; eliminar espécies que
38
co-existem com todas as outras ou seja, espécies com ampla distribuição
temporal foram retiradas da análise para se evitar erro na correlação.
O método das associações unitárias trará zoneamentos alternativos
aos depósitos da Fm. Solimões, pois acredita-se que os zoneamentos
estabelecidos para esta região têm sido feitos em seções cujos intervalos são
pequenos e não seções completas como têm sido interpretadas. Essa
premissa, da qual parte esse trabalho, se deve ao fato de que, quando
comparamos ao Mioceno de outras regiões (Urumaco na Venezuela com
cerca de 9 km), encontramos seções com apenas 300 metros de espessura
na Amazônia interpretadas como abrangendo quase todo o Mioceno Hoorn
1993. Sendo que, esse intervalo recobre menos de 30% do valor mínimo
descrito para a espessura da Fm. Solimões (Caputo et al. 1971).
39
5.0 Resultados e discussões
5.1 Sistemática
Menos de 10 trabalhos palinológicos do Mioceno e Plioceno do norte
da América do Sul foram realizados desde a década de 60 (Germeraad et al.
1968, Regali et al. 1974, Lorente 1986, Muller et al. 1987 Hoorn 1993). Desde
então, todos os grãos e esporos foram descritos utilizando-se a mesma
nomenclatura genérica proposta e empregada em Van der Hammen 1956b.
Jansonius e Hills (1976) afirmam que os gêneros descritos
principalmente nos trabalhos de Van der Hammen são gêneros inválidos
devido à utilização de grãos atuais como espécies-tipo para suportar a
descrição do gênero fóssil.
Gêneros com nomenclatura artificial amplamente utilizada em
palinologia, tais como: Psilatricolporites, Retitricolporites e Fenestrites,
necessitam ser revisados e trocados por nomes genéricos válidos.
Por outro lado, nomes de gênero que usam caracteres morfológicos
deveriam ser evitados (artigo 20.2), de acordo com o Código Internacional de
Nomenclatura Botânica (Código de Saint Louis, 2000),
Nesse trabalho, foram detalhadamente descritos e revisados no total
112 esporomorfos. Desses, 51 são esporomorfos descritos pela primeira vez
na literatura. Sete novas combinações, aplicando-se gêneros válidos, foram
propostas como sugerida pelo Código.
Essa revisão resultou em um detalhado trabalho taxonômico e
sistemático que está sendo revisado com as morfoespécies encontradas nos
poços 1AS-19-AM e 1AS-27-AM e que será brevemente submetido. No
anexo 1 encontra-se o manuscrito (em fase de revisão) que será submetido a
Paleontographica B, nível B internacional (segundo Qualis-CAPES).
40
5.2- Bioestratigrafia
5.2.1- Bioestratigrafia tradicional
De acordo com a bioestratigrafia tradicional as seções aqui estudadas
são interpretadas e correlacionadas da seguinte maneira:
1) 1AS-27-AM: esta sondagem possui duas biozonas: 1) intervalo mais
inferior, (354.5 m a 221 m): Zona de Asteraceae- subzona de Fenestrites-
descritas por Lorente (1986) como características do Mioceno Superior; 2)
intervalo superior (221 m até 43 m): zona de Psilatricolporites caribbiensis
que pertence ao Plioceno.
Na amostra mais antiga (400 m) não foi observada a presença de
nenhum importante marcador, aqui o incluiremos no intervalo da Zona de
Asteraceae. Em todo o intervalo estudado, houve presença de Grimdalea
magnaclavata e Crassoretitriletes vanraadshoovenii.
2) 1AS-19-AM: toda a seção estudada de 218 m pertenceria à zona de
Psilatricolporites caribbiensis, devido a presença do marcador estratigráfico
que tem o mesmo nome da zona. Esta seção seria correlacionada com a
parte superior da sondagem anteriormente descrita.
A correlação entre poços encontra-se na figura 10.
41
Figura 10: Correlação estratigráfica usando a bioestratigrafia tradicional
da região.
Levando-se em consideração a presença dos marcadores
bioestratigráficos, essas duas seções são mais recentes do que o poço 1AS-
4a-AM estudado por Hoorn (1993) e são contemporâneas com o poço 1AS-
33-AM de Leite (2007).
De acordo com a bioestratigrafia tradicional, as associações
encontradas em seções do Mioceno Superior/Plioceno são compostas de
três importantes grãos: Fenestrites spinosus, Pachydermites diederixii
(Symphonia) e Stephanocolpites evansii (Rubiaceae, Borreria?). No entanto,
nenhum desses três marcadores foi observado em nossas duas seções.
Lorente (1986) reporta que Pachydermites diederixii somente é
encontrado em uma das três Bacias por ela estudada, a Bacia da Oriental da
Venezuela, sendo completamente ausente das Bacias de Falcon e
42
Maracaibo. O mesmo ocorre em sedimentos do Quaternário, observando-se
diagramas polínicos da Amazônia Absy 1979, Symphonia está apenas
registrada em duas (lago cuminã e Costa da Terra Nova-IA) das seis seções
analisadas. Nessas localidades, a freqüência do grão de Symphonia
apresenta baixa percentagem, com menos de 5% de toda associação
polínica sendo, portanto, considerado raro.
A ausência de Pachydermites diederixii provavelmente possa estar
relacionada à especificidade de habitat da planta ou baixa incidência
populacional no Mio/Plioceno da Amazônia. Germeraad et al. 1968) sugerem
que Symphonia globulifera ocorre em áreas de pântanos costeiras na África e
América do Sul, mas Ribeiro et al. (1999) descreve que atualmente
Symphonia globulifera está presente na floresta de terra firme na Reserva
Ducke, Amazônia Central com ampla distribuição e freqüência.
No caso do o grão de Stephanocolpites evansii, Lorente (1986),
coloca o seu primeiro aparecimento na zona NN11 de nanoplâncton e na
zona de foraminíferos planctônicos Globorotalia dutertrei e Globorotalia
acostaensis (Tortoniano/Mioceno Superior). Muller et al. (1987) registra o
primeiro aparecimento de Stephanocolpites evansii no Plioceno.
Hoorn (1994) também registra a presença de Stephanocolpites
evansii em seções da Colômbia e Peru de Três Islãs III, Mariname III, Santa
Sofia, Mocagua, Los chorros I E e Pijuayal.
A ausência de marcadores “raros” na associação faz com que sejam
estabelecidas idades errôneas a algumas seções como provavelmente, foi
publicado por Hoorn (1994) que ignora a presença de um marcador do
Mioceno Superior/Plioceno (Stephanocolpites evansii) devido a ausência de
outras espécies do Mioceno Superior. Apesar dessa importante interpretação,
e como enfatizado em Latrubesse et al. (2007), novas seções necessitam ser
estudadas e um novo zoneamento feito para avaliar essas inconsistências
antes de se inferir idade para sedimentos.
As biozonas estabelecidas para o Mioceno e Plioceno estão baseadas
na ocorrência de poucas espécies marcadoras de idade ou espécies que
aparecem em baixa freqüência no registro fossilífero.
McGowran (2005) afirma que os bons marcadores bioestratigráficos
apresentam duas características: abundância no registro e ampla dispersão
43
geográfica. Fato não observado em seções do Mioceno Superior e Plioceno.
Uma outra característica fundamental na procura por espécies-guia é o fácil
e exato reconhecimento morfológico do grão.
Na tabela 2 está descrito o zoneamento elaborado para a Venezuela e
usado na Amazônia.
44
Tabela 2: Zonas palinológicas estabelecidas para Venezuela e Amazônia.
45
As espécies-guias usadas para marcar o Mioceno Inferior (tabela 1)
possuem grande controle ambiental como no caso de V. rotundiporus. As
outras possuem baixo potencial de fossilização (Psiladiporites minimus,
Echitricolporites maristellae). Psiladiporites minimus tem afinidade botânica
com Fícus (Moraceae), que de acordo com Bush (1995) é raramente
fossilizado devido à baixa produção de pólen e sua especificidade com o
polinizador. No caso de Echitricolporites maristellae, normalmente sua
presença é marcada sempre pela baixa freqüência na associação.
O oposto acontece no Mioceno Médio e Médio/Superior, pois existem
dois excelentes marcadores que caracterizam esse intervalo
(Crassoretitriletes vanraadshoovenii e Grimsdalea magnaclavata). Eles são
bons marcadores devido à alta freqüência observada tanto nos seus
primeiros aparecimentos quanto em todo o intervalo de sua existência.
Quanto à extinção desses marcadores, somente Grimsdalea se torna extinto
provavelmente, no início do Pleistoceno (Lorente 1986).
Em relação ao Mioceno Superior e Plioceno, o grande problema é que
os grãos utilizados apresentam sempre baixa freqüência nas associações
(e.g. Fenestrites spinosus e Fenestrites longispinosus (Asteraceae),
Psilatricolporites caribbiensis, Stephanocolpites evansii (Borreria?),
Pachydermites diederixii (Symphonia) e Echitricolporites mcneilly (Ambrosia-
Asteraceae).
Em parte isso se deve a síndrome de polinização que em áreas
tropicais que tendem a ser especificas e com baixa produção polínica quando
comparadas a aquelas anemófilas (Bush 1995). Por isso, há necessidade em
encontrar outras espécies mais eficientes que possam ser utilizadas como
marcadores do Mioceno Superior e Plioceno na Amazônia.
No anexo 2 está um trabalho publicado que trata sobre os erros de
interpretação cometidos na literatura usando-se os elementos
palinoestratigráficos atuais.
Como pode ser observado nas cartas de distribuição dos poços 1AS-
27-AM (Fig. 13) e 1AS-19-AM (Fig. 14), a freqüência dos marcadores:
Fenestrites longispinosus (Cichoreacidites longispinosus) e Psilatricolporites
46
caribbiensis (Horniella? caribbiensis) é sempre menor que 3% da associação
(Figuras 11 e 12).
Outro problema observado foi o primeiro registro de Clavainaperturites
microclavatus (Hedyosmum) em seções da Colômbia e Peru. Hoorn (1994)
interpreta seu primeiro registro no Mioceno Médio. Entretanto, nesse mesmo
trabalho, Clavainaperturites microclavatus está associado a Stephanocolpites
evansii em muitas seções tais como, Santa Sofia, Mocagua, Los chorros I E,
Pijuayal, o que indica idade mais recente para essas localidades.
Van der Hammen et al. (1973) registra o primeiro aparecimento de
Hedyosmum nos Andes colombianos ocorrendo no Plioceno Inferior.
Entretanto, o primeiro aparecimento de Hedyosmum ainda permanece em
discussão, pois em seções estudadas na Colômbia pelo Instituto Colombiano
del Petróleo esta espécie aparece desde o Mioceno Médio (Rueda,com.
pess.). A. Antonelli (com. pess.) afirma que o primeiro clado de Hedyosmum
começa a radiar a 11.2 Ma.
Diante do exposto, e baseando-se nas zonas estabelecidas para o
Mio/Plioceno, as presenças de Fenestrites longispinosus e Psilatricolporites
caribbiensis indicam, de acordo com a bioestratigrafia tradicional, que as
seções são mio/pliocenicas, sendo esse, juntamente com o poço 1AS-33-AM
Leite 2007, os primeiros registros de seções dessa idade na Amazônia.
Certa precaução será tomada em referir-se ao Plioceno, pois novos
métodos de bioestratigrafia quantitativa deverão ser aplicados além de novas
localidades amostradas para se poder afirmar essa idade para seções da Fm.
Solimões no Estado do Amazonas.
47
Figura 11: Carta de distribuição do 1AS-27-AM
48
Figura 12: Carta de distribuição do 1AS-19-AM.
49
5.2.2- Bioestratigrafia quantitativa
Devido aos fatores mencionados no tópico de Bioestratigrafia
tradicional, foi optado pelo o uso de métodos quantitativos para evitar erro na
interpretação de dados devido a ausência de marcadores ocasionada pela
baixa freqüência no registro polínico.
De acordo com o método de Associação unitária, e confirmando a
interpretação dada anteriormente, as duas seções foram correlacionadas e
são contemporâneas (Figura 13), permitindo assim que algumas biozonas
sejam estabelecidas.
Figura 13: Correlações estratigráficas usando-se o método de
Associação Unitária
50
A Associação Unitária apresentou em 2 AU’s resultantes de 5 cliques
maximal (maximal cliques) e 12 máximos residuais. Somente 2 contradições
foram encontradas.
Os cliques maximal foram encontrados nos intervalos: seção 27-
161,2m, 27- 280,2m, 19-143m, 19-4,5m e 19- 218m. Isso significa que
nessas seções/amostras foram encontrados o número máximo de espécies
co-ocorrendo do que em qualquer outro intervalo. Já que o método trabalha
com zonas de amplitude (Concurrent zone), é a partir desses cliques maximal
que as AU são sugeridas.
As figuras 14
a e b ilustram os gráficos de co-ocorrência (a) e
superposição (b) entre as espécies. Observa-se que todas as espécies
correlacionam entre si, isso significa dizer que as espécies têm uma ampla
distribuição geográfica e temporal, tornando-se difícil a correlação entre
localidades por separação em zonas. No entanto, o gráfico de superposição
mostra que a espécie 20 (Margocolporites muelleri) tem superposição com 8
espécies, sendo esta uma importante característica para a escolha do bom
marcador.
Os números dos vértices correspondem às espécies (tabela 3). O
método permitiu o estabelecimento de duas zonas, aqui chamadas de AU 1 e
AU 2.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
B
51
Figura 14: A) gráfico não Orientado, onde os números correspondem as
espécies (vértices) e as setas em azul (arestas) correspondem a relação
de co -ocorrência entre as espécies, B) gráfico Orientado, onde os
números correspondem as espécies (vértices) e as setas em vermelho
(arcos) correspondem a relação de superposição entre as espécies.
A UA 1 é composta de 80% da associação polínica e a presença de
Margocolporites muelleri n. sp. está restrito a essa zona. A UA 2 tem 8
espécies presentes nessa zona (tabela 3). A tabela 3 mostra a composição
de espécies usada para construir cada UA e as zonas de intervalo sugeridas.
No total 8 espécies, sendo que a maioria delas é novas espécies,
apresentam-se como bons marcadores bioestratigráficos locais:
Bombacacidites fossulatus, Clavainaperturites microclavatus, Margocolporites
muellerae, Retitrescolpites sp. 2, Retitriletes murielevatus, Siltaria sp.1,
Striasyncolporites anastomosus e Echiperiporites estelae. Entretanto, esses
marcadores também apresentaram baixa freqüência polínica na associação.
Tabela 3: Tabela mostrando a composição de cada UA. Em amarelo está
a associação típica da UA2. Em azul a espécie encontrada somente na UA1.
Na seção intermediária estão as espécies das UA1/2. A primeira coluna
corresponde aos números contidos nos gráficos orientados e não orientados.
2
Bombacacidites fossulatus
5
Clavainaperturites microclavatus
9
Echiperiporites estelae
29
Retistephanocolporites sp1
32
Retitriletes murielevatus
31
Retitrescolpites sp2
35
Siltaria sp1
37
Striasyncolporites anastomosus
1
Arecipites perfectus
3
Bombacacidites nacimentoensis
4
Bombacacidites zuatensis
6
Crassiectoapertites colombianus
52
7
Ctenolophonidites suigeneris
8
Echinatisporis muelleri
10
Echiperiporites intectatus
11
Foveotricolporites pseudodubiosus
12
Heterocolpites incomptus
13
Heterocolpites rotundus
14
Heterocolpites verrucosus
15
Horniella caribbiensis
16
Horniella morenae
17
Hydrosporis minor
18
Kuylisporites waterbolkii
19
Ladakhipollenites floratus
21
Margocolporites pseudodemicolpatus
22
Margocolporites vanwijhei
23
Parsonsidites brennacII
24
Podocarpites sp
25
Polypodiisporites planus
26
Proteacidites triangulatus
27
Proxapertites tertiaria
28
Psilastephanoporites herngreenii
30
Retistephanoporites crassiannulatus
33
Rhoipites gigantiporus
34
Rhoipites guianensis
36
Siltaria tectus
38
Striatricolporites digitatus
39
Striatricolporites poloreticulatus
40
Tetracolporopollenites sp1
41
Tricolpites sp
20
Margocolporites muellerae
O poço 1AS-27-AM mostrou associação presente nas duas UA’s e
funcionou como modelo para comparar com o 1AS-19-AM. Como dito
anteriormente, de acordo com UA, as seções são contemporâneas e a
correlação entre poços sugerida.
O uso das espécies com potencial estratigráfico aqui sugerido e
mostrado na tabela 3 servirá para avaliar sua aplicabilidade em outras seções
e Bacias.
53
5.3- Paleoecologia
A paleoecologia contribui para a compreensão da biodiversidade em
uma ampla escala de tempo e área geográfica (Odgaard 1999). De acordo
com Morley (2000) os registros de grãos de pólen e esporos evidenciam
padrões da vegetação em escala regional devido a sua ampla dispersão,
produção e facilidade em fossilizar em vários ambientes de deposição.
Entretanto, essas evidências deveriam ser interpretadas com precaução
devido a problemas tafonômicos, que poderiam interferir na qualidade do
registro fossilífero.
Alguns indicadores paleopalinológicos de florestas tropicais poderiam
ser a identificação de famílias tropicais tais como: Annonaceae,
Combretaceae, Malvaceae (Dilleniaceae, Bombacaceae) e Guttiferae, além
de mudanças na abundância polínica de determinados tipos de vegetação
(Morley 2000).
Nesse estudo foi registrada a presença de muitas famílias
denominadas tropicais, tais quais: Bombacaceae e Annonaceae indicando
condições tropicais similares as atuais com uma floresta bem estruturada. No
entanto, nossos resultados mostraram abundância de esporos, gramíneas e
palmeiras, fato relacionado a alta produção e facilidade de dispersão desses
esporomorfos.
5.3.1- Relação abundância e raridade na composição palinológica
Observou-se na composição palinoflorística abundância de esporos
nas associações dos dois intervalos estudados (Figura 15 e 16), com mais de
50% do total da associação encontradas nos dois poços.
54
Figura 15: Gráfico de freqüência (%) de esporos, famílias de
angiospermas e gimnospermas encontradas no Poço 1AS-27-AM.
Figura 16: Gráfico de freqüência de esporos, famílias de angiospermas e
gimnospermas encontradas no Poço 1AS-19-AM.
Esses resultados corroboram com os trabalhos de Hoorn (1993), Rull
(2001) e Leite (2007) que registram abundâncias de Laevigatosporites
tibuensis e Polipodiisporites usmensis em seções do Mioceno Inferior até o
Mioceno Superior/Plioceno. Este fato pode ser explicado pela alta resistência
de esporos ao transporte a longas distâncias e a alterações ambientais
55
(Poumot 1989; Playford e Dettman 1996). Por outro lado, a necessidade por
localidades mais úmidas para dispersão de esporos, poderia estar
favorecendo a representação desses em nossa análise palinológica.
Em ambientes costeiros, a abundância em esporos indicaria uma
baixa no nível do oceano. Durante este intervalo, a atividade fluvial se torna
mais ativa, transportando mais esporos, que devido a sua melhor resistência,
se fossilizam com mais facilidade (Poumot 1989).
Os esporos triletes (Crassoretitriletes vanraadshoovenii, Deltoidosporis
adriennis) e os monoletes (Laevigatosporites tibuensis e Polypodiisporites
usmensis) indicam a presença de ambiente com alta umidade e com árvores,
pois a maioria das pteridófitas encontradas na associação polínica possui
afinidade botânica atual com espécies com hábitos de lianas, epífitas ou
hemi-epífitas, como mostrado na tabela 4.
Tabela 4: Afinidade botânica e hábito de alguns esporos que
apresentaram abundância na associação.
Nome Fóssil
Afinidade
botânica
Hábito
Referência
Echitriletes muelleri
Selaginella
Ervas
Ribeiro et al. 1999
Crassoretitriletes
vanraadshoovenii
Lygodium
Lianas/hemiepífitas
Ribeiro et al. 1999
Magnastriatites
grandiosus
Ceratopteris
Ervas aquáticas
Frederiksen 1985
Polypodiaesporites
gemmatus
Pteris
Porte arbóreo
Ribeiro et al. 1999
Polipodiisporites
usmensis
Polypodium
Epífitas
Ribeiro et al. 1999
Laevigatosporites
Lianas
Frederiksen 1985
Além de esporos, houve também predominância de grãos de Poaceae
e Arecaceae nas duas seções estudadas. Isso se deve a síndrome de
polinização dessas plantas que por dispersarem os grãos pelo vento
necessitam de alta produtividade polínica. Bush (1995) afirma que apesar de
as plantas anemófilas serem raras em florestas tropicais (2.5% de todas as
árvores), elas são bem representadas no espectro polínico (27%).
56
Essa facilidade em dispersão pode se explicar o padrão encontrado
em sedimentos do Mioceno/Plioceno. O autor acima citado também, afirma
que plantas presentes na proximidade de lagos ou pântanos têm maior
chance em aparecer no registro em relação a aquelas de floresta de terra
firme.
A presença de gramíneas poderia estar indicando dois tipos de
ambientes distintos: 1) de vegetação aberta tipo savana ou cerrado e, 2)
ambientes próximos a rios ou lagos e que, se acumulam em forma de
“floating meadows” (Absy 1979). Estudos do Pleistoceno utilizam a alta
freqüência de gramíneas no registro polínico para inferir a presença de áreas
abertas na Amazônia (Van der Hammen 1972) e suportar a idéia de refúgios,
porém essa interpretação tem sido avaliada (Absy 1979).
A expansão de gramíneas no Mioceno Superior poderia também estar
relacionada com o grande aporte de sedimentos ricos em nutrientes vindos
dos Andes Hoorn 1993 e co-evolução com animais pastadores (grazers)
como peixes-boi (Retallack 2001).
Em relação às palmeiras, a maioria delas indica áreas de pântanos
Absy 1979. Esses dois elementos, somado a abundância de esporos,
indicam áreas aquáticas/pantanosas nas proximidades das áreas
amostradas.
A tabela 5 representa as estratégias reprodutivas, mecanismos de
polinização e hábitos das plantas que tem seus grãos de pólen representados
nesse estudo. Informações retiradas de Bush (1995) e Morley (2000).
Tabela 5: Tabela com alguns tipos polínicos encontrados e suas
informações botânicas.
Tipos de pólen
Estrutura
reprod.
Polinizadores
Alchornea
Dióica
Vento
Poaceae
Monóica
Vento
Mauritia
Dióica
Insetos generalistas
Euphorbiaceae
Mon/dio
Ins. gen/abelhas
Tubuliflorae
Hermafrodita
Ins. gen./borboletas
Arecaceae
Mono/dio
Insetos generalistas
Ilex
Dio/Herm
Insetos generalistas
Cróton
Monóica
Insetos generalistas
Loranthaceae
Herm/mon
Insetos generalistas
57
Malpighiaceae
Hermafrodita
Abelhas
Malvaceae
Herm/Dio
Abelhas
Polygonum
Hermafrodita
Abelhas
Rubiaceae
Hermafrodita
Abelhas
Sapium
Monóica
Insetos generalistas
Amanoa
Monóica
Insetos generalistas
Apocynaceae
Hermafrodita
Abelhas
Caryophyllaceae
Hermafrodita
Abelhas
Ludwigia
Hermafrodita
Abelhas
Pachira
Hermafrodita
Morcegos
Podocarpus
Monóica
Vento
Byttneria
Hermafrodita
Abelhas
Gomphrena
Hermafrodita
Abelhas
Humiria
Hermafrodita
Abelhas
Dois padrões são bem distinguíveis em análises palinológicas de
sedimentos da Amazônia: poucas espécies muito abundantes e muitas
espécies raras. Essa mesma tendência também é encontrada em estudos de
inventários florísticos em florestas tropicais (Terborgh e Andresen 1998).
Bush (1995) faz uma comparação entre mecanismos reprodutivos e a
representação de grãos de pólen no registro polínico. Ele encontrou que
plantas monóicas e dióicas são mais bem representadas do que as
hermafroditas. Isso explicaria em parte, a baixa freqüência de Byttneria,
Gomphrena e Caryophyllaceae (menos que 3 grãos cada) registrada em
nosso estudo.
Em relação à espécies raras, e como pode ser observado no diagrama
polínico, a maioria dos grãos encontrados pode ser considerados raros (<3%
da associação) ou aparecendo somente uma vez no registro.
5.3.2- Famílias de angiospermas predominantes
No poço 1AS-27-AM (figura 19), cerca de 4330 grãos foram contados
(com exceção a contagem dos esporos). Em 28% da associação não foi
possível determinar a afinidade botânica/ecológica dos grãos. Esses
elementos aparecem raramente na associação (muitas vezes somente um
grão é encontrado) e/ou possuem morfologia simples, o que dificulta
comparações com grãos descritos e conhecidos atualmente. Resultados
58
similares são descritos em Bush (1995), onde 70-98% são grãos identificados
a nível genérico ou de família.
Cerca de 30 famílias puderam ser identificadas e a seqüência de
abundância foi: Arecaceae, Poaceae, Bombacaceae (aqui essa família será
mantida devido a diferença morfológica entre grãos de Bombacaceae e
Malvaceae, Euphorbiaceae (Alchornea), Malpighiaceae, Humiriaceae
(Humiria) e Melastomataceae (Miconia).
Bush et al. 2001) afirmam que altos valores de pólen de
Euphorbiaceae (Alchornea) associado com alta diversidade de grãos de
pólen raros são bons indicadores da presença de floresta de terra-firme. Em
todo perfil do poço foi encontrado pólen de Euphorbiaceae, sendo que na
parte inferior em maior abundância.
De acordo com Webster (2004) a maior diversidade genérica dessa
família é encontrada na Amazônia, principalmente devido aos gêneros
endêmicos dessa região. A figura abaixo (Figura 17) representa a contagem
e predominância de grãos feita por amostra no poço 1AS-27-AM.
59
Figura 17: Diagrama palinológico com abundância de esporomorfos no
poço 1AS-27-AM.
No poço 1AS-19-AM, somente 910 grãos foram contados, totalizando
19 famílias, sendo que Poaceae, Arecaceae, Malpighiaceae, Euphorbiaceae,
Bombacaceae, Melastomataceae e Onagraceae tiveram predominância (fig.
18).
60
A composição e abundância nos dois poços apresentaram grande
similaridade, poucas exceções podem ser ressaltadas como a presença de
grãos de Polygonaceae.
Figura 18: Diagrama palinológico com abundância de esporomorfos a
nível de família/gênero no poço 1AS-19-AM.
61
Gentry (1988) registra 11 famílias abundantes que são: Leguminosas,
Lauraceae, Annonaceae, Rubiaceae, Moraceae, Myristicaceae, Sapotaceae,
Meliaceae, Palmae (Arecaceae), Euphorbiaceae e Bignoniaceae, sendo que
estas contribuem em média com 52% da riqueza de espécies em florestas
neotropicais.
Dentre essas 11 famílias, somente 7 foram encontradas no registro
polínico, pois esses grãos são facilmente reconhecidos em nível de família e
gêneros.
De forma geral, a tabela abaixo mostra todas as famílias e gêneros
encontrados na Amazônia durante o Mioceno Superior/Plioceno.
Tabela 6: Afinidade botânica de alguns fósseis
Família
Gênero
Nome fóssil
Acanthaceae
Sanchezia
Multimarginites vandehammenii
Teliostachya
Retitrescolpites? traversei
Amaranthaceae
Gomphrena
Gomphrenipollis minimus
Annonaceae
Crematosperma
Proxapertites tertiaria
Apocynaceae
Rauvolfia
Retibrevitricolpites hoornii
Arecaceae
Mauritia
M.franciscoi
Asteraceae
Tubuliflorae
Echitricolporites spinosus
Liguliflorae
Fenestrites longispinosus
Chloranthaceae
Hedyosmum
Clavainaperturites microclavatus
Euphorbiaceae
Croton
Crototricolpites type,
Crotonoideaepollenites
reticulatus
Sapium
Horniella? caribbiensis
Alchornea
Ranunculacidites operculatus
Humiriaceae
Humiria
Psilabrevicolporites devriesi
Loranthaceae
Loranthacites psilatus
Malpighiaceae
Brachypteris,Bunchosia,
Hiraea, Mascagnia,
Stigmatophyllum, Tetrapterys
Perisyncolporites pokorny
Malvaceae
Byttnerioidea: Byttnneria,
Ayennia
Byttneripollis ruedae
Bombacoideae:Pachira
Bombacacidites baculatus
Bombacoideae:Ceiba
Bombacacidites aracuarensis
Bombacoideae: Quararibea
Retistephanoporites
crassiannulatus
Bombacoideae: Bombacopsis
Bombacacidites muinaneorum
62
Thespesia, Hibiscus ou
Convolulaceae
Echiperiporites estelae
Melastomataceae
Miconia
Heterocplpites incomptus
Onagraceae
Ludwigia
Corsinipollenites type
Phyllanthaceae
Amanoa, Pseudolachnostylis
Retitrescolpites? irregularis
Poaceae
Monoporopollenites annulatus
Polygonaceae
Polygonum
Glencopollis curvimuratus
Rubiaceae
Psychotria
Inaperturopollenites solimoensis
5.3.3 Primeiros registros de famílias e gêneros na Amazônia
Aproximadamente 200 morfo-espécies foram identificadas e alguns
gêneros/famílias descritos pela primeira vez no registro fossilífero da
Amazônia, devido a facilidade de reconhecimento morfológico. São eles:
Sapium (Euphorbiaceae), Byttneria (Malvaceae), Polygonum (Polygonaceae),
Rauvolfia e Geissospermum (Apocynaceae), Loranthaceae, Psychotria
(Rubiaceae), Caryophyllaceae e Gomphrena (Amaranthaceae), sendo esses
registros atualmente, muito importantes para a calibração de relógios
moleculares. O RADAMBRASIL registra a presença da maioria dessas
plantas atualmente na área de estudo.
Na tabela 7 estão descritas as características botânicas dessas
famílias. Essas informações foram retiradas de Ribeiro et al. (1999).
Tabela 7: Informações botânicas das famílias/Gêneros registrados pela
primeira vez na Amazônia.
Família
Gênero
Hábito
Ambiente
Amaranthaceae
Gomphrena
Ervas
Ambientes
pertubados
Apocynaceae
Geissospermum
Árvores de dossel
Platôs e
vertentes
Rauvolfia
Árvores sub-
bosque
Campinaranas
Caryophyllaceae
herbáceo ou
subarbustivo
Pioneiras em
solos expostos
Euphorbiaceae
Sapium
Árvores
Platôs e
vertentes
Loranthaceae
Hemi-parasitas
Polygonaceae
Polygonum
Rubiaceae
Psychotria
Vários hábitos
Vários ambientes
63
Como se pode observar com esses registros, a floresta Amazônica
possuía representantes com vários hábitos e adaptados diferentes
ambientes, indicando a presença de uma floresta bem-estruturada com
árvores de dossel, árvores e arbustos de sub-bosque, hemi-parasitas e
espécies pioneiras distribuídas em distintos ambientes.
5.3.4 Diversidade da Amazônia durante o Neógeno
Por muitos anos acreditou-se que a diversidade da Amazônia estava
relacionada a eventos de especiação causados pelo isolamento da biota por
meio da fragmentação de florestas por extensas áreas abertas tipo savana.
Essa fragmentação teria ocorrido por adaptação das espécies frente às
mudanças climáticas ocorridas no Quaternário (Haffer 1969).
Essa hipótese foi amplamente discutida (Colinvaux et al. 2000) e
atualmente dados moleculares tem suportado a diversificação da Amazônia
antes das mudanças ocorridas no Pleistoceno.
Corroborando com uma diversificação mais antiga do que a
inicialmente proposta, Hooghiemstra e Van der Hammen (1998) compararam
números de grãos de pólen e esporos encontrados em amostras de
sedimentos do Mioceno e Quaternário de Caquetá na Colômbia e afirmaram
que no Mioceno a Amazônia foi mais diversa do que é atualmente.
Essa diversidade estaria relacionada à dinâmica ambiental ocasionada
por incursões marinhas, mudanças na drenagem de rios e soerguimento da
cordilheira oriental.
Um fato também que deve ser ressaltado é a influência ocasionada
pela conexão com a América do Norte por meio do Istmo do Panamá que
ocorreu no Plioceno (Coates et al. 1992), permitindo a imigração de taxa
entre esses continentes (Morley 2000).
Fazendo-se a mesma comparação feita por Hooghiemstra e Van der
Hammen (1998) foram encontrados em 33 amostras de sedimentos
Mio/Pliocênicos 197 morfo-espécies. Absy (1979) registra em 72 amostras
64
de sedimentos retirados na localidade de Costa da Terra Nova, na Amazônia,
apenas 91 tipos de grãos, corroborando com a afirmação acima citada.
Entretanto, quando se refere à diversidade usando-se dados
palinológicos, alguns fatores necessitam ser mencionados e levados em
consideração antes de serem feitas essas comparações:
1) Ambiente de deposição seria um importante fator, sendo
que ambientes lacustre teriam vantagem em relação a
ambientes fluviais.
2) Número de grãos contados por amostra, pois quando maior
o número de grãos contados maior será o número de
espécies encontradas e, portanto, a diversidade será maior.
3) Estudos de Quaternário não fazem muita diferenciação
entre esporos, sendo que sempre são criadas grandes
categorias morfológicas tais como: monolete psilado,
monolete verrugado, etc.
4) A separação morfológica de grãos é subjetiva, sendo que
alguns palinológicos preferem juntar como mesma espécie
grãos com variações morfológicas e outros, que preferem
separar as espécies que são unidades morfologicamente
distintas.
De qualquer modo, nossos dados sugerem que mais do que um
aumento ou decréscimo no número de espécies entre o Terciário e
Quaternário, a diversidade na Amazônia poderia ser explicada pela
estabilidade no número de espécies ao longo do tempo geológico.
Pelo menos, é o que se observa no Mioceno e Plioceno, onde não há
grandes eventos de origens e extinções de espécies nos dois intervalos
estudados. Essa ausência de eventos bem marcados dificulta também a
aplicação de conceitos bioestratigraficos nessas seções.
A razão de altas taxas de especiação e baixa de extinção usada para
explicar a diversidade em florestas tropicais, não foi observada nesse estudo.
Provavelmente, a escala temporal aqui estudada, tenha sido tão pequena a
ponto de não mostrar nenhum padrão. No entanto, esse seria um dado que
65
poderia ser testado em outros estudos, principalmente aqueles que abordam
estudos polínicos no Quaternário.
De forma geral, no poço 1AS-19-AM observa-se grandes diferenças
entre o número de espécies observadas entre amostras, porém isso se deve
a grandes intervalos entre as amostragens. O número mínimo de espécies foi
25 (amostra 189) e máximo de 45 espécies (amostra 90) com média de 33
espécies. Entretanto, diferenças maiores são observadas no poço 1AS-27-
AM, onde se encontra 19 espécies na amostra 400.5 m e 59 espécies na
amostra 192 m com media de 35.5 espécies.
.
66
6.0 Conclusões
1) Foram descritas 112 morfo-especies encontradas em amostras de rochas
do Neógeno da Amazônia, sendo essa a primeira revisão sistemática dos
grãos já descritos para o Norte da América do Sul, resultando em sete novas
combinações e cerca 51 novos grãos. Sendo muitos deles encontrados pela
primeira vez no registro fossilífero.
2) Em relação à bioestratigrafia, foram encontrados dois marcadores
estratigráficos anteriormente estabelecidos (Fenestrites spinosus e
Psilatricolporites caribbiensis) e indicadores do Mioceno Superior e Plioceno.
No entanto, devido a sua baixa freqüência (<3% da associação), foi aplicado
métodos de Bioestratigrafia Quantitativa. Resultando, em novas biozonas que
deverão ser testadas em outras seções para avaliar sua aplicabilidade.
3) Conforme já discutido em trabalhos paleontológicos, nenhuma evidência
de áreas marinhas ou costeiras foi encontrada, sendo rejeitada, portanto, a
hipótese de um “seaway” na Amazônia durante o Mioceno Superior.
4) Abundância de esporos, gramíneas e palmeiras sugerem a presença de
áreas pantanosas e aquáticas. A presença de muitas famílias de
angiospermas indica áreas de florestas de terra firme nas proximidades da
localidade de deposição.
5) Sugerimos que a floresta foi bem estruturada com a presença de sub-
bosques e dossel e grande diversidade de epífitas além de espécies
pioneiras.
6) A diversidade no Mioceno/Plioceno pelo menos nos intervalos estudados
não ocorreu devido a altas taxas de especiação somadas a baixas de
extinção, aparentemente, o que se observa hoje na Amazônia é devido à
longa estabilidade no número de famílias ao longo dos últimos milhões de
anos.
67
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93.
Webb, S. D. 1995. Biological implications of the Middle Miocene Amazon
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Renema, W.; Romero-Pittman, L. Gringas, M. K. 2002. Lake Pebas: a
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72
8.0 Anexos
73
ANEXO I: MANUSCRITO QUE SERÁ SUBMETIDO A
PALAEONTOGRAPHICA B.
Neogene palynology of Upper Amazonas Basin, South America, Brazil.
Silane A. F. Da Silva
1,2
, Carlos A. Jaramillo
2
, Maria Lucia Absy
1
, Millerlandy
Romero-Baez
2
.
1
Instituto Nacional de Pesquisas da Amazonia-INPA,. Coordenação de Pós-
graduação em Ecologia-PGEC, Laboratório de Palinologia-CPBO. P.O Box-
478, Cep: 69011-970 Manaus, AM, Brazil.
2
Smithsonian Tropical Research Institute-CTPA. Apartado 0843-03092,
Balboa, Ancon, Panamá.
Summary:
Neogene palynology in the North South America has been poorly studied.
Most of the palynological studies have been conducted in the coastal regions
of Colombia and Venezuela with the objective of improving the
biostratigraphical framework to be applied to oil research. So far, very few
have done a detailed palynological study emphasizing a taxonomic revision of
the pollen grains and spores. We are presenting a taxonomic revision of the
Neogene Brazilian Amazonia using core sediments collected from Solimões
Formation in Amazonas state, Brazil. We studied 41 samples of two sections
located in northwestern Amazonia. A total of 112 species were described,
being 51 new species. In addition, 7 previously described species were also
revised in order to apply valid genus, as suggested by the ICBN. The age of
those sections were established based on the presence of Fenestrites
longispinosus and Clavainaperturites microclavatus (Hedyosmum) as Late
Miocene/Early Pliocene. We also used Unitary association analysis to
improve the biochronological framework and to determine correlations
between those sections. As biostratigraphical results we found that the
sections are contemporaneous.
Keywords: Palynology- taxonomy- Pliocene- Amazonia- Unitary Association.
Zusammenfassung
Die neogene Palynologie in Amazonien wurde bisher wenig erforscht. Die
meisten Studien wurden in den Küstengebieten von Kolumbien und
Venezuela mit dem Ziel durchgeführt, den palniostratographischen Rahmen
zur Ölsuche zu verbessern. Es gibt bisher sehr wenige palynologische
Studien mit dem Schwerpunkt auf taxonomischer Revision. Wir präsentieren
eine palynologisch taxonomische Revision des neogenen basilianischen
Amazonien mit Hilfe von Sedimenten aus Solimoes Formationen. Wir
untersuchten 41 Arten zweier Sektionen in Nordwest Amazonien. Wir
beschreiben insgesamt 112 Arten, von denen 51 neue Arten sind. Zusätzlich
wurden 7 bereits beschriebene Arten revidiert um diese einer korrekten
Gattung, wie vom ICBN vorgeschlagen, zuzuordnen. Wir benutzten die
Unitary Association Analyse zur Bestimmung von biostratographischen
Korrelationen zwischen diesen Sektionen, welche demnach gleichzeitig
entstanden sind. Aufgrund des Vorkommens von Clavainaperturites
microclavatus (Hedyosmum) datieren wir das Alter der Sedimente in das
Pliozän.
Schlusselworter: Palynologie – Taxonomie – Pliozän – Amazonien - Unitary
Association
Table of Contents
1. INTRODUCTION .........................................................................................3
2. METHODOLOGY ........................................................................................3
2.1 STUDY AREA.............................................................................................3
2.2- BIOSTRATIGRAPHICAL ANALYSIS................................................................4
2.3 PREPARATION OF THE SAMPLES AND DESCRIPTION OF THE GRAINS ...............5
3. RESULTS ....................................................................................................5
3.1 BIOSTRATIGRAPHYCAL RESULTS ................................................................5
3.2 SYSTEMATICAL PART.................................................................................7
3.2.1 SPORES..........................................................................................7
3.2.2 POLLEN ........................................................................................22
5. ACKNOWLEDGEMENTS .........................................................................79
6. REFERENCES ..........................................................................................79
1. Introduction
Few palynological studies in the northern South America have been
conducted. Most of the research has discussed the vegetation response to
both Pleistocene and Holocene climatic changes and human impacts (Bush
Bush, 2005, 2005). Others have emphasized improvement of the Tertiary
palynostratigraphical framework for oil exploration research in coastal zones
from Colombia, Venezuela, Trinidad and Brazil.
Miocene and Pliocene in the northern South America have been
palynologically studied since the 1960’s (Germeraad, et al., 1968, Regali, et
al., 1974, Lorente, 1986, Muller, et al., 1987 and Hoorn, 1993). Since that
time, the same pollen and spores nomenclature has been used. However,
some nomenclatural problems can be emphasized: 1) posterior studies have
been accepted some invalid genera, mainly that ones described in Van der
Hammen 1954, 1956a and b, that use recent pollen as species type to
support the genera description (Jansonius and Hill, 1976) and 2) according to
International Code Botanical Nomenclature-ICBN-St. Louis 2000 (article 20.2)
generic names that use morphological characteristics should be avoid unless
if it was published before 1912.
In order to do a complete revision of the systematical nomenclature
applied to pollen and spores in northwestern South America, a detailed
description of the sporomorphs found in the Neogene sediments from
Amazonia is herein present. A total of 112 species, proposing 51 new species
and 7 new combinations are described.
2. Methodology
2.1 Study area
The sediments herein studied were drilled by the CPRM-Brazilian Geological
company-in the 1970’s to find out potential areas to lignite exploration.
Approximately 80 wells were drilled in that area reaching Neogene sediments
belonging to the Solimões Formation (Moraes-Rego, 1930; Caputo, 1984) in
the Upper Amazonas area, Brazil.
The Solimões Formation is lithologically composed by grayish to gray-
greenish clays, separated by sandbanks, lignite and gipsy levels Caputo,
1973, Schobbenhaus, et al., 1984 typically deposited in a lacustrine/fluvial
environments Caputo, 1973. The unity shows Miocene and Pliocene deposits
and is paleontologically known by the vertebrate and invertebrate fossiliferous
sites, found mainly in Acre state.
Two cores were studied in the present study: The well 1AS-27-AM
(04°17’S/67°5’W) with 402, 5 meters depth near to Tamanduá-Jutaí Rivers in
Amazonas State, Brazil. The well 1AS-19-AM (04°33’S/69°10’W) with 255,70
meters deep, Felicidade–Rio Jandiatuba Rivers, near to São Paulo de
Olivença city, Amazonas state, Brazil. Their locations and of the another wells
studied in the same area can be observed in text-Fig. 1.
In this work just the Upper part of Solimões Formation was analyzed. The
presence of Fenestrites longispinosus indicates late Miocene/Early Pliocene
Lorente, 1986. Clavainaperturites microclavatus characterizes Pliocene age
based on First Appearance Datum (FAD) dated in Colombia as Zone II
belonging to Early Pliocene Van der Hammen, et al., 1973.
2.2- Biostratigraphical analysis
The Neogene biostratigraphical framework used in this work was compared
with previous biozonations established by Germeraad, et al., 1968, Regali, et
al., 1974, Lorente, 1986, Muller, et al., 1987 and Hoorn, 1993. However, to do
some biostratigraphical correlation between our cores, we used
Unitary Association method, herein cited as UA Guex, 1991. The UA method
uses a species matrix to establish assemblages showing co-occurrences,
superposition and/or exclusive relations between species. It creates a
biochronological assemblages, describing a sequence of intervals of events.
Taxa assemblages can be used to construct zones with chronological
meaning and consequently, correlation between the different sections can be
made. For detailed information, see Guex, 1991 and its application in
Angiolini&Bucher, 1999 Mailliot, et al., 2006. The software PAST Hammer, et
al., 2001 was used. 35 species were chosen to compose the analysis taken
into account two considerations: 1) species that show narrow distribution (i.e.,
wide range species were removed) and 2) the species present in both
sections.
2.3 Preparation of the samples and description of the grains
The samples were prepared in ICP-Instituto Colombiano del Petroleo
following the standard palynological method Traverse, 1988. About 41
samples were studied, and approximately 300 grains were counted by slide.
The holotypes and paratypes described here were deposited in the
Palynology Laboratory at the INPA-Instituto Nacional de Pesquisas da
Amazônia- INPA/Manaus, Brazil. The sporomorphs are organized in genera
alphabetical order. The new combinations are proposed when the genera
used in the literature is an invalid name as discussed in Jansonius&Hills,
1976. To determine valid genera, we used the key to the genera fossil
Jansonius, 1978.
To indicate new species distinctive morphological characteristics were taken
into account and at least two grains were measured. The coordinates are
given using an England Finder (EF) slide.
The pollen grains and spores were described using the nomenclature used by
Punt, et al., 2007, and following descriptions based on Jaramillo&Dilcher,
2001.
For pollen grains found in polar view, CPi (colpi length/equatorial diameter),
equatorial length, equatorial width and equatorial diameter length/width and in
equatorial view CEi (colpi length/polar diameter), polar diameter, equatorial
diameter and polar/equatorial (P/E) measurements were taken.
Spores found in lateral view were measured both equatorial diameter and
polar diameter. Equatorial diameter length and equatorial diameter width
were measured in polar view. To indicate the relation between the radius and
the spore diameter, the TLI (radius length /(trilete spore diameter/2) and MLI
(laesura length/(monolete spore diameter) also were taken.
3. Results
3.1 Biostratigraphical results
The biozonation established by Lorente (1986) were used to compare with our
data. The Fenestrites longispinosus Interval Zone proposed to late
Miocene/Early Pliocene is based on the first appearance of Stephanocolpites
evansii and the top is characterized by the first occurrence of Alnipollenites
verus. The Fenestrites longispinosus is present in the entire interval of the
zone. The zone is divided in three subzones: Stephanocolpites evansii
Interval Subzone, Psilatricolporites caribbiensis Interval Subzone,
Echitricolporites-Alnipollenites Interval Subzone.
Despite of the absence of the Stephanocolpites evansii, the assemblage
found in the Amazonas sections indicates late Miocene/Early Pliocene, based
on the presence of Psilatricolporites caribbiensis.
Data input from Solimões Formation in Unitary association method were
composed of 2 sections, 41 samples and 35 species data were used. The UA
analysis resulted in 5 maximal cliques based on 11 residual maximal
horizons, 2 contradictions and 2 unitary associations. The 5 maximal cliques
were found in the samples: Oboh-Ikuenobe, et al., 19-11, (2) 19-2, (3) 27-98,
(4) 19-6 and Oboh-Ikuenobe, et al., 27-60. The contradictions were found
mainly in the pairs of cliques: 2-5 and 1-6. No forbidden graphs were
generated. The biostratigraphic graph for the sporomorphs is in text-fig. 2 and
it shows strong co-occurrences between all species (figure 2a) and their
superposition (figure 2b).
3.1.1- Unitary association zones:
- UA 1 and UA 2
In text-figure 3 is a graphical representation of the species composition used
to construct each UA. The UA 1 is composed by 77% of the assemblage. The
presence of Margocolporites muelleri n. sp. is restricted to this zone.
The sections are contemporaneous according to UA reproducibility. The well
1AS-27-AM showed assemblages of all UA’s and it worked as a model to
compare with another section. The correlation between sections and
relationship with UA’s is in text-Fig. 4. Comparisons between sections were
based on the extension of the UA’s range assumed by the presence of the
lowest and uppers UA’s assemblages.
3.2 Systematical part
3.2.1 SPORES
Genus Cingulatisporites Pflug&Thomson, 1953 in
Thomson&Pflug, 1953
Cingulatisporites pteriformis n. sp.
Plate 1, Figs. 1,2,3
Diagnosis: Trilete, triangular-obtuse-convex, mid-sized (39-40 µm), laevigate
on the both faces, marginate.
Specimens: AM27-24, EF: O 46 ½, pl. 1, figs 1,2,3, AM27-2, EF: K39 2
Description: Spores single, symmetry radial, triangular-obtuse-convex; trilete,
curvatura absent, radii ~17 µm, TLI 1, commissurae raised, borders convex,
ends rounded, margo very thick, 3 µm thick, margo protruding, highly distinct,
reaching the equator; sporoderm 1 µm thick; cingulate, cingulum 7 µm thick,
decreasing to 4 µm towards radial area; sculpture laevigate on both faces.
Dimensions: equatorial diameter length 39 (39.5) 40 µm, SD 0.7; equatorial
diameter width 37(40.5) 44 µm, SD 4.9; P/dv length/width 1, n=2.
Comparisons: Cingulatisporites Pflug&Thomson, 1953 in Thomson&Pflug,
1953 accommodates cingulate trilete spores.
Cingulatisporites rugulatus n. sp.
Plate 1, Figs. 4,5,6
Diagnosis: Trilete, triangular-obtuse-convex to circular, mid-sized (22 µm),
rugulate on proximal face and scabrate on the distal face, cingulate, curvatura
perfecta.
Specimens: Holotype: AM27-31, EF: W26 ¾, pl. 1, figs 4,5,6
Type locality: Well 1AS-27-AM
Etymology: After the ornamentation on proximal face
Description: Spores single, symmetry radial, triangular-obtuse-convex to
circular; trilete, curvatura perfecta present, TLI 1, commissurae waving, margo
distinct; sporoderm 1 µm thick; cingulate, cingulum 2 µm thick; sculpture
rugulate on proximal face and scabrate on distal face. Dimensions: equatorial
diameter length 22 µm; equatorial diameter width 22 µm; P/dv length/width 1,
n=1.
Comparisons: Cingulatisporites ornatus (van Hoeken-Klinkenberg 1964) has
cingulum thicker (5 µm) and laesura indistinct.
Genus Crassoretitriletes Germeraad, et al., 1968
Crassoretitriletes vanraadshoovenii Germeraad et al. 1968.
Plate 1, Fig. 7
Diagnosis: Trilete, triangular-obtuse-convex to subcircular, big-sized (51-80
µm), reti-fossulate.
Specimens: AM27-22, EF: M55 2/4; 27-153, EF: N26 3 pl. 1, fig. 7
Description: Spores single, symmetry radial, triangular-obtuse-convex to
subcircular, rounded corners; trilete, curvatura absent, radii 28 µm, TLI 0.87,
margo absent, comissurae straight, ends pointed; sporoderm thick,
sporoderm 5 µm thick; sculpture reti-fossulate, coarsely reticulate, muri 3 µm
wide, 4 µm high, lumina varying from elongated to circular, 2-3 µm wide.
Dimensions: equatorial diameter length 51 (62.5) 80 µm, SD 12.8; equatorial
diameter width 55 (63.5) 80 µm, SD 11.6; P/dv length/width 1, n=4.
Genus Cyathidites Couper 1963 emend. Romanovskaya 1980
Cyathidites sp. 1
Plate 1, Figs. 8,9
Diagnosis: Trilete, triangular-obtuse-concave, mid-sized (35 µm), slightly
cingulate, laevigate, granulate near to laesurae.
Specimens: AM27-19, EF: V33 1/2 pl. 1, figs 8,9
Description: Spores single, symmetry radial, triangular-obtuse-concave;
trilete, curvatura perfect, radii 18 µm, TLI 1, reaching the equator, margo 0.5
µm near to equator, increasing to 1 µm near to trilete mark, commissurae
straight; intexine 0.4 µm thick; cingulate, cingulum 2 µm thick; sculpture
laevigate, granulate near to laesurae. Dimensions: equatorial diameter length
35µm; equatorial diameter width 36 µm; equatorial/polar diameter 1 µm, n=1.
Comparisons: Cyathidites Couper 1963 emend. Romanovskaya 1980
accommodates triangular spores with rounded angles and straight to concave
sides (Jansonius & Hills, 1983, card 4084).
Genus Deltoidospora Miner, 1935 Potonié, 1956
Deltoidospora adriennis Potonié&Gelletich, 1933 Frederiksen,
1983
Plate 1, Figs. 16
Diagnosis: Trilete, triangular-obtuse-convex to subcircular, big-sized (43-85
µm), laevigate.
Specimens: AM27-26, EF: L49 3/4 pl. 1, figs 16
Description: Spores single, symmetry radial, triangular-obtuse-convex to
subcircular, rounded corners; trilete, curvatura absent, radii 15 µm, TLI 0.66,
margo absent, comissurae straight, ends pointed; intexine 2 µm thick;
sculpture laevigate on both faces. Dimensions: equatorial diameter length 43
(59.3) 85 µm, SD 22.5; equatorial diameter width 45 (60) 87 µm, SD 23.4;
P/dv length/width 1, n=3.
Genus Distaverrusporites Muller, 1968
Distaverrusporites margaritatus Muller, 1968
Plate 1, Figs. 11,12,13,14
Diagnosis: Trilete, triangular-obtuse-convex, mid-sized (26 µm), gemmate-
verrucate on distal face and laevigate on proximal face.
Specimens: AM27-27, EF: U51 ½ pl. 1, figs 11,12,13,14
Description: Spores single, symmetry radial, triangular-obtuse-convex; trilete,
curvatura absent, radii 13 µm, TLI 1.0, margo 1 µ m, commissurae straight; at
the end of each radii, there are prominent gemmae that are larger than the
another; intexine 1 µm thick; sculpture gemmate-verrucate on distal face, 4
µm high, 3-4 µm wide, verrucae also are present, 2 µm high, 3 µm wide, both
verrucae and gemmae are mixed together, no pattern were observed,
laevigate on proximal face. Dimensions: equatorial diameter length 26 (27) 28
µm, SD 1.4; equatorial diameter width 23 (23.5) 24 µm, SD 0.7;
equatorial/polar diameter 1.2, n=2.
Genus Echinatisporis Krutzsch, 1959
Echinatisporis circularis n. sp.
Plate 1, Figs. 15,16
Diagnosis: Trilete, circular to subtriangular, mid-sized (17-23µm), echinate on
both proximal and distal faces, spines cylindrical, curvatura perfecta.
Specimens: Holotype AM27-23, EF: Y34 1 pl. 1, figs 15,16, paratype: AM27-
23, EF: M 24 1.
Type locality: Well 1AS-27-AM
Etymology: After the spore shape
Description: Spores single, symmetry radial, circular; trilete, curvatura
perfecta, laesura distinct, radii 10 µm, TLI 1, margo absent, commissurae
straight; intexine 1 µm thick; sculpture echinate, echinae 1.5- 2 µm high, 1 µm
thick, 1-2 µm apart, spines cylindrical, tips pointed. Dimensions: equatorial
diameter length 17 (20) 23 µm, SD 4.2; equatorial diameter width 16 (18) 20
µm, SD 2.8; equatorial/polar diameter 1.1 µm, n=2.
Comparisons: Echitriletes muelleri Regali, et al., 1974 has longer spines (> 6
µm and larger (32-35 µm). Echinatisporis minutus Van der Kaars, 1983 has
laesura indistinct. Echinatisporis brevispinosus Jaramillo&Dilcher, 2001 has
margo.
Echinatisporis muelleri Regali et al. 1974 n. comb.
Plate 1, Fig. 21
1974 Echitriletes muelleri Regali et al., p. 265 pl. 14, Fig. 8.
Diagnosis: trilete, circular, mid-sized (27 µm), echinate, spines 6-9 long,
sparsely distributed.
Specimens: AM27-30, EF: X26 3 pl. 1, fig. 21
Description: Spores single, symmetry radial, circular; trilete, curvatura
indistinct, laesura also indistinct; intexine 1.5 µm thick; sculpture echinate,
echinae 6-9 µm long, 1-2 µm thick, 7 µm apart, sparsely distributed, echinae
present in both faces, surface interspines laevigate. Dimensions: equatorial
diameter length 27 µm; equatorial diameter width 20 µm; equatorial/polar
diameter 1.4 µm, n=1.
Comparisons: Echitriletes Van der Hammen 1955 is a nomen nodum
Jansonius&Hills, 1976. Echitriletes Potonié 1956 accommodates trilete
megaspores (Jansonius&Hills, 1976). Echinatisporis Krutzsch, 1959
accommodates spores triangular-convex to subcircular spores with spines
distributed all over spore surface.
Genus Foveotriletes Van der Hammen ex Potonié, 1956
Foveotriletes ornatus Regali, et al., 1974
Plate 1, Figs. 17,18
Diagnosis: Trilete, triangular-obtuse-convex, mid-sized (28µm), foveolate on
distal face and laevigate on proximal face, intexine decreases towards radial
area.
Specimens: AM27-23, EF: W 30 1/2, pl. 1, figs. 17,18
Description: Spores single, symmetry radial, triangular-obtuse-convex; trilete,
curvatura absent, radii long, TLI 1.0, commissurae simple, margo absent,
borders straight, ends distinct; intexine 1.5 µm thick, decreasing to 0.5 µm
towards radial area; sculpture laevigate on the proximal face, foveolate on the
distal face, foveos 0.5-1 µm wide, circular, 2-3 µm apart. Dimensions:
equatorial diameter length 28 µm; equatorial diameter width 29 µm; P/dv
length/width 1, n=1.
Genus Hydrosporis KRUTZSCH, 1962
Hydrosporis minor n. sp.
Plate 1, Figs. 23,24
Diagnosis: Trilete, circular, small-sized (15-17 µm), laevigate, thin margo,
margo granulate, thick exine.
Specimens: Holotype AM27-17, EF: U28 ½ pl. 1, figs 23,24
Type locality: Well 1AS-27-AM
Etymology: After the small size of the spore.
Description: Spores single, symmetry radial, circular; trilete, curvatura absent,
laesura distinct, radii 8 µm, TLI 1.0, reaching the equator, margo very thin,
margo <1µm, granulate, commissurae straight; intexine very thick, 1.5 µm
thick; sculpture laevigate, thickness constant. Dimensions: equatorial
diameter length 15 (16) 17 µm, SD1.4; equatorial diameter width 16 µm; P/dv
length/width 1 µm, n=2.
Comparisons: Hydrosporis Krutzsch, 1962 accommodates laevigate spores
with morphology that are known in Salvinia and Azolla’s spores
Jansonius&Hills, 1976 card 1278. Psilatriletes martinensis SARMIENTO,
1992 has thicker sporoderm (3-4 µm)
Affinities: Salvinia, Salviniaceae.
Genus Kuylisporites Potoníe, 1956
Kuylisporites waterbolkii Potoníe, 1956
Plate 1, Figs. 19,20
Diagnosis: Trilete, triangular-obtuse-straight, mid-sized (29 µm), laevigate.
Specimens: AM27-2, EF: E36 1, pl. 1, figs 19,20
Description: Spores single, symmetry radial, triangular-obtuse-straight; trilete,
curvatura absent, laesura distinct, radii 10 µm, TLI 0.7, almost reaching the
equator, margo absent, commissurae straight, ends pointed, corners flats;
interradial thickening with a aperture resembling a large pori, rounded, 8 µm
wide; intexine 1-3 µm thick; sculpture laevigate. Dimensions: equatorial
diameter length 29 µm; equatorial diameter width 31 µm; P/dv length/width
0.9 µm, n=1.
Genus Magnastriatites Germeraad et al. 1968
Magnastriatites grandiosus Kedves&De Porta, 1963 Dueñas,
1980
Plate 1, Fig. 22
Diagnosis: Trilete, triangular-obtuse-straight, big-sized (76 µm), cicatricosate
on distal face, laevigate on proximal face.
Specimens: AM27-1, EF: T31 ½ pl. 1, fig. 22
Description: Spores single, symmetry radial, triangular-obtuse-straight; trilete,
curvatura absent, laesura distinct, radii 20 µm, TLI 0.3, margo 2 µm,
commissurae straight; sporoderm 2-layered, 5 µm thick; sculpture
cicatricosate on distal face, striae 3 µm high, 4 µm wide, 3 µm apart, laevigate
on proximal face. Dimensions: equatorial diameter length 56 (64.6) 76 µm, SD
7.6; equatorial diameter width 55 (64.4) 75 µm; P/dv length/width 1.0 µm, n=9.
Genus Matonisporites Couper, 1958 emend. DETTMANN, 1963
Matonisporites muelleri Playford 1982
Plate 1, Figs. 29,30
Diagnosis: Trilete, triangular-obtuse-straight, mid-sized (24-30µm), laevigate.
Specimens: AM27-2, EF: S25 2, pl. 1, figs 29,30
Description: Spores single, symmetry radial, triangular-obtuse-straight; trilete,
curvatura perfect, radii 12 µm, TLI 1.0, reaching the equator, margo thin, 1 µm
thick commissurae straight to waving; intexine1 µm thick, thickness increasing
towards radial area to 1.5 µm; sculpture laevigate. Dimensions: equatorial
diameter length 24 (39.7) 65 µm, SD 22.1; equatorial diameter width 20 (34.7)
60 µm, SD 22; equatorial/polar diameter 1.2 µm, n=3.
Genus Microfoveolatosporis Krutzsch 1959
Microfoveolatosporis sp.1
Plate 1, Figs, 27, 28
Diagnosis: Monolete, reniform, mid-sized (51µm), foveolate, marginate.
Specimens: AM27-23, EF: L35 ¾ pl. 1, figs. 27,28
Description: Spores single, symmetry bilateral, reniform; monolete, curvatura
absent, laesura with 30 µm, MLI 0.58, marginate, margo 2 µm wide, margo
segmented, commissurae straight, ends pointed; intexine 2.0 µm thick;
sculpture foveolate, foveolae 1-2 µm wide, 2-3 apart, 0.5-1 µm deep, circular
to slightly elongate, uniformly distributed. Dimensions: equatorial diameter 52
µm; polar diameter 32 µm; equatorial/polar diameter 1.6, n=1.
Comparisons: Microfoveolatosporis Krutzsch 1959 accommodates monolete
and foveolate spores with foveolae shallow and rounded. Foveomonoletes
Van der Hammen, 1954 ex MATHUR, 1966 also accommodates foveolate
monolete spores. However, the type species, Foveomonoletes brevitriletes, is
smaller (39µm), the mark is smaller (17µm) and has margo poorly developed.
Microfoveolatosporis skottsbergii Selling, 1946 Srivastava, 1971 is larger (60-
89µm) and foveolae are densely distributed.
Genus Polypodiaceiosporites Potonié 1951 ex Potonié 1956
Polypodiaceiosporites? laevigatus n. sp.
Plate 1, Figs. 25,26
Diagnosis: Trilete, triangular-obtuse-straight, mid-sized (28-40µm), fossulate
on distal face and laevigate on proximal face.
Specimens: Holotype: AM27-2, EF: K38 3 pl. 1, figs 25,26
Description: Spores single, symmetry radial, triangular-obtuse-straight,
corners rounded; trilete, curvatura absent, radii ~10 µm, TLI 0.7, almost
reaching the equator, commissurae straight, ends rounded to pointed; intexine
1 µm thick; cingulate, cingulum 2 µm thick; sculpture fossulate on distal face,
fossulae varying from rounded to elongated, of 2 to 10 µm long, borders
rounded, 1-2 µm wide, muri 1.5 wide, laevigate on proximal face. Dimensions:
equatorial diameter length 28 (34) 40µm, SD 6; equatorial diameter width 32
(34) 36 µm, SD 2; P/dv length/width 1, n=3.
Comparisons: Polypodiaceoisporites? fossulatus Jaramillo&Dilcher, 2001 is
verrucate on proximal face. Polypodiaceiosporites pseudopsilatus Lorente,
1986 is rugulate on distal face. Cingulatisporites verrucatus Regali, et al.,
1974 is verrucate and has cingulum thicker (6-8 µm thick). Foveotriletes sp. 1
(Jaramillo & Dilcher, 2001) is not cingulate.
Polypodiaceiosporites pseudopsilatus Lorente 1986
Plate 2, Figs. 1,2,3
1994a Psilatriletes peruanus Hoorn, p. 234, Pl. 2, Fig.10
Diagnosis: Trilete, triangular-obtuse-straight, mid-sized (27 µm), foveo-
fossulate-rugulate on distal face and laevigate on proximal face, with a
triangular ridge in distal face.
Specimens: AM27-2, EF: K38 3 pl. 2, figs 1,2,3
Description: Spores single, symmetry radial, triangular-obtuse-straight,
corners rounded; trilete, curvatura absent, radii indistinct in the observed
grains, margo distinct, 2 µm wide, commissurae almost reaches the equator,
commissurae straight, ends pointed; sporoderm 1-layered, intexine 1 µm
thick; cingulum 2-3 µm thick, decreasing in radial region; sculpture foveolate-
fossulate-rugulate on distal face, laevigate on proximal face, with a triangular
ridge in distal face. Dimensions: equatorial diameter length 27 µm; equatorial
diameter width 27 µm; P/dv length/width 1, n=1.
Genus Polypodiisporites Potonié1931? in Potonié&Gelletich,
1933 ex 1956, emend. Khan&Martin, 1972
Polypodiisporites aff. specious Sah, 1967
Plate 2, Figs. 6,7
Diagnosis: Monolete, reniform, mid sized (42-44 µm), verrucate on the distal
face and scabrate on proximal face.
Specimens: AM27-33, EF: L53 ½ pl. 2, figs 6,7
Description: Spores single, symmetry bilateral, reniform; monolete, curvatura
absent, laesura indistinct; intexine 1 µm thick; sculpture verrucate on distal
face, warts 1-2µm high, 2-3 µm wide and scabrate on the proximal face,
evenly distributed. Dimensions: equatorial diameter 42 (43) 44 µm, SD 1.4;
polar diameter 30 (30.5) 31 µm, SD 0.71; equatorial/polar diameter 1.4, n=2.
Comparisons: Polypodiisporites aff. specious Sah, 1967 accommodates a
wide variation of spores that have warts flats. Polypodiisporites usmensis Van
der Hammen, 1956 Germeraad, et al., 1968 Khan&Martin, 1972 is also
gemmate.
Polypodiisporites pseudoreticulatus n. sp.
Plate 2, Figs. 4,5
2001 Polypodiisporites aff. inangahuensis, Jaramillo & Dilcher, 2001, p. 104,
Pl.3, Figs.16,17,18
Diagnosis: Monolete, reniform, mid-sized (48-49 µm), positive reticulum,
verrucate on distal face and scabrate on proximal face.
Specimens: Holotype AM27-23, EF: Q33 2 pl. 2, figs 4,5, paratype AM27-22,
EF: S31 3.
Type locality: Well 1AS-27-AM.
Etymology: After the false reticulum.
Description: Spores single, symmetry bilateral, reniform; monolete, curvatura
absent, laesura length 32 µm, MLI 0.6, commissurae straight to slightly
convex; intexine 2.5µm thick; sculpture verrucate, verrucae narrow, forming a
negative reticulum, uniformly distributed, scabrate on proximal face.
Dimensions: equatorial diameter 48 (48.5) 49 µm, SD 0.7; polar diameter 34
(36) 38 µm, SD 2.8; equatorial/polar diameter 1.4 µm, n=2.
Comparisons: Polypodiisporites specious Sah, 1967 and Polypodiisporites aff.
specious Sah, 1967 do not form negative reticulum.
Polypodiisporites usmensis Van der Hammen, 1956 Germeraad, et al.,
1968 Khan&Martin, 1972
Plate 2, Figs. 8,9
Diagnosis: Monolete, reniform, mid-sized (35-42 µm), verrucate-gemmate in
both faces.
Specimens: AM27-25, EF: D54 3 pl. 2, figs. 8,9
Description: Spores single, symmetry bilateral, reniform; monolete, curvatura
absent, laesura 25 µm long, MLI 0.7, commissurae straight; intexine 1 µm
thick; sculpture verrucate and gemmate, verrucae 1-2 µm high, 2 µm wide,
gemmate, gemmae 3 µm high, 3 µm wide, 1-2 µm apart, warts distributed
uniformly for whole surface. Gemmae more prominent on the extremities of
the grain. Dimension: equatorial diameter length 35 (38.5) 42 µm, SD 4.95;
equatorial diameter width 20 (24) 28 µm, SD 5.66; P/Dv length/width 1.7, n=2.
Equatorial diameter 32 µm, polar diameter 16 µm, equatorial/polar diameter 2,
n=1.
Polypodiisporites? planus n. sp.
Plate 2, Figs. 10,11
Diagnosis: Monolete, reniform, mid-sized (35-41µm) clavate-gemmate on
distal face and scabrate on proximal face.
Specimens: Holotype AM27-20, EF: Q43 2, pl. 2, figs 10,11, paratype: 27-46,
EF: Y36 1
Type locality: Well 1AS-27-AM
Etymology: After the top of the clave shape
Description: Spores single, symmetry bilateral, reniform; monolete, curvatura
absent, laesura 25 µm, MLI 0.6, commissurae straight; intexine 1 µm thick;
sculpture clavate to gemmate, sculpture 3 µm high, 2-3 µm wide, 3-5 µm
apart, rounded to polygonal in plain view, head of clavae is not well
developed, sometimes looks like a box, sparsely distributed, scabrate on
proximal face. Dimensions: equatorial diameter 35 (38) 41µm, SD 4.2; polar
diameter 20 (21.5) 23 µm, SD 2.1; equatorial/polar diameter 1.8, n=2.
Comparisons: Polypodiisporites aff. inangahuensis Couper, 1953 Potonié,
1956 emend. Pocknall&Mildenhall, 1984, Polypodiisporites specious Sah,
1967 and Polypodiisporites aff. specious Sah, 1967 are verrucate.
Polypodiisporites sp. 1 (Jaramillo & Dilcher, 2001) is smaller (26-35µm) and
densely clavate.
Genus Psilatriletes Van der Hammen, 1956, Van der Hammen,
1954 ex Potonié, 1956
Psilatriletes lobatus Hoorn, 1994
Plate 2, Figs. 12,13
Diagnosis: Trilete, triangular-obtuse-convex, mid-sized (25 µm), laevigate,
interradial crassitude.
Specimens: AM27-33, EF: V22 4, pl. 2, figs. 12,13
Description: Spores single, symmetry radial, triangular-obtuse-convex; trilete,
curvatura absent, laesura distinct, radii 7 µm, TLI 0.7, slightly marginate 1 µm,
commissurae straight, ends pointed; intexine 0.5 µm, interradial crassitude
well developed, 3 µm in radial area increasing to 8 µm towards interradial
area; sculpture laevigate. Dimensions: equatorial diameter length 26 µm;
equatorial diameter width 29 µm; P/dv length/width 0.9 µm, n=1.
Psilatriletes sp.1
Plate 2, Figs. 14,15
Diagnosis: Trilete, circular, mid-sized (15-17 µm), laevigate, trilete mark
reaches the equator.
Specimens: AM27-26, EF: K 63 3 pl. 2, figs 14,15
Description: Spores single, symmetry radial, circular; trilete, curvatura absent,
laesura distinct, radii 10 µm, TLI 0.7, margo <1µm, commissurae convex,
ends pointed; sporoderm 1-layered, intexine 0.4 µm thick; interradial
crassitude, 2 µm thick, decreasing to 0.5 µm towards radial region; sculpture
laevigate with small perforations on distal face. Dimensions: equatorial
diameter length 26 µm; equatorial diameter width 17 µm; P/dv length/width 1
µm, n=1.
Comparisons: Psilatriletes lobatus (Hoorn, 1994a) the interradial crassitude is
thicker (8 µm).
Genus Pteridaceoisporis SUN&HE, 1980
Pteridaceoisporis gemmatus n. sp.
Plate 2, Figs. 16,17,18
Diagnosis: Trilete, triangular-obtuse-convex, mid-sized (28-42µm), rugulate
on distal face and gemmate on proximal face, thick cingulum.
Specimens: Holotype AM27-2, EF: U 39 4, pl. 2, figs 16,17,18, paratype:
AM27-2, EF: V24 1
Type locality: Well 1AS-27-AM
Etymology: After the gemmate sculpturing
Description: Spores single, symmetry radial, triangular-obtuse-convex; trilete,
curvatura absent, radii 10 µm, TLI 0.6, margo absent or indistinct, comissurae
concave, ends pointed; intexine 0.8 µm thick; cingulate, cingulum very thick, 5
µm thick; sculpture rugulate on distal face, rugulae 7 µm long, 2 µm wide, 5
µm apart, sparsely distributed, on distal face near to equator there is a zonate
ridge just above the cingulum, verrucate, verrucae 1-2 µm long, 1 µm high
and 1 µm apart, gemmate on proximal face, gemmae 1-2 µm high, 1 µm wide,
2 µm apart, circular, densely distributed. Dimensions: equatorial diameter
length 28(34.7) 42 µm, SD 7; equatorial diameter width 37(38.3) 40 µm, SD
1.5; P/dv length/width 0.9, n=3.
Comparisons: Pteridaceoisporis Sun & He 1980 accommodates triangular to
circular spores with cingulum, verrucae on distal face and verrucae, granulae
or scabrate on proximal face Jansonius&Hills, 1983 card 4145.
Polypodiaceoisporetes pseudopsilatus LORENTE, 1986 has proximal face
laevigate. Polypodiaceoisporites? fossulatus JARAMILLO&DILCHER, 2001 is
verrucate-fossulate.
Genus Retitriletes Pierce 1961
Retitriletes altimuratus n. sp
Plate 2, Figs. 25,26
Diagnosis: Trilete, circular, mid-sized (39-40 µm), reticulate, muri raised.
Specimens: Holotype: AM27-10, EF: U29 2, pl. 2, figs. 25,26 paratype: AM27-
8, EF: Q29 2
Type locality: Well 1AS-27-AM
Etymology: After the raised condition of the muri.
Description: Spores single, symmetry radial, circular; trilete, laesura indistinct;
intexine 1 µm thick; sculpture reticulate, lumina 2-3 µm wide, polygonal,
evenly distributed, muri 0.5 µm thick, the point of intersection of the muri is
raised to 1 µm. Dimensions: equatorial diameter length 39 (39.5) 40 µm, SD
0.71; equatorial diameter width 36 (37) 38 µm, SD 1.4; P/dv length/width 1.4
µm, n=2.
Comparisons: Retitriletes sp. 1 (Jaramillo & Dilcher, 2001) is larger (60 µm),
muri is taller (2 µm) and lumina wider (5-7 µm).
Genus Rugulatisporites Pflug&Thomson, 1953 in
Thomson&Pflug, 1953
Rugulatisporites sp. 1
Plate 2, Figs. 21, 22
Diagnosis: Trilete, triangular-obtuse-convex, mid-sized (27 µm), laevigate on
proximal face and rugulate on distal face.
Specimens: AM27-8, EF: Y36 ½ pl. 2, figs 21, 22
Description: Spores single, symmetry radial, triangular-obtuse-convex; trilete,
curvatura absent, laesura distinct, short, radii 11 µm, TLI 0.7, margo absent,
comissurae slightly waving and concave, ends pointed; intexine 0.5 µm thick;
sculpture laevigate on proximal face and rugulate on distal face, muri 0.5 um
wide, 3-4 µm long, elongated, groove 0.5 µm apart, evenly distributed on
proximal face. Dimensions: equatorial diameter length 27 µm; equatorial
diameter width 31 µm; P/dv length/width 0.9 µm, n=1.
Comparisons: Rugulatisporites Pflug&Thomson, 1953 in Thomson&Pflug,
1953 accommodates trilete spores that has elongated elements with uniform
heights and irregularly distributed Jansonius&Hills, 1976, card 2460.
Camarozonosporites sp. 1 Jaramillo&Dilcher, 2001 has interradial crassitude.
Genus Tuberositriletes Doring 1964
Tuberositriletes? crassus n. sp.
Plate 2, Figs. 19,20
Diagnosis: Trilete, triangular-obtuse-convex, mid-sized (27-30µm), verrucate
on distal and proximal faces, interradial crassitude.
Specimens: Holotype AM27-18, EF: V32 3/4 pl. 2, figs 19,20
Type locality: Well 1AS-27-AM
Etymology: After the presence of interradial crassitude.
Description: Spores single, symmetry radial, triangular-obtuse-convex; trilete,
curvatura absent, radii 12 µm, TLI 0.8, margo absent or indistinct,
commissurae almost reaches the equator, commissurae straight, ends
pointed; intexine 1 µm thick, increasing to 2-3 µ m towards interradial region;
interradial crassitude, 2-3 µm thick; sculpture verrucate, on proximal face
verrucae shorter, 1 µm wide, rounded, on distal face is bigger, 1-3 µm high, 1
µm apart. Dimensions: equatorial diameter length 27 (28.5) 30 µm, SD 2.1;
equatorial diameter width 27 (28.5) 30 µm, SD 2.1; P/dv length/width 1, n=2.
Comparisons: These specimens are provisionally inserted in this genus.
Tuberositriletes no accommodates spores that have interradial crassitude.
Psilatriletes lobatus (Hoorn, 1994a) is psilate.
Genus Verrucatotriletes Van Hoeken-Klinkenberg, 1964
Verrucatotriletes bullatus VAN HOEKEN-KLINKENBERG, 1964
Plate 2, Figs. 23,24
Diagnosis: Trilete, triangular-obtuse-straight, mid-sized (30 µm), verrucate.
Specimens: AM19-5, EF: J32 3/4 pl. 2, figs 23,24
Description: Spores single, symmetry radial, triangular-obtuse-straight; trilete,
curvatura absent, laesura distinct, long, reaching the equator, radii 18 µm, TLI
1.0, margo absent, commissurae straight; intexine 1 µm thick; sculpture
verrucate on both proximal and distal faces, irregularly distributed, on distal
face are larger 10 µm wide and 3 µm high, on proximal face, 3 µm wide, 2 µm
high, circular to elongated. Dimensions: equatorial diameter length 30 µm;
equatorial diameter width 25 µm; P/dv length/width 1.2 µm, n=1.
3.2.2 POLLEN
Genus Arecipites Wodehouse, 1933 emend. Nichols, et al.,
1973
Arecipites perfectus n. sp.
Plate 3, Figs. 1, 2
Diagnosis: monocolpate, prolate, mid-sized (39-46 µm), micropitted, tectate,
colpi mid-sized, borders straight, ends pointed, tapered.
Specimens: Holotype AM27-23, EF: O23 ½ pl. 3, figs. 1,2, paratype AM27-32,
EF: R22 4
Biochronological range: from UA 1 to UA 3.
Etymology: After the perfect sculpture of the grain.
Description: Monad, bilateral, anisopolar, prolate; monocolpate, colpi mid-
sized, ends pointed, borders straight, tapered, colpi simple, colpi 38 µm long,
CEi 0.4; tectate, exine 1 µm thick, nexine 0.3 µm thick, columellae 0.3 µ m
high, distinct, tectum 0.4 µm thick; sculpture micropitted, lumina < 0.3 µm,
circular to elongated, densely distributed, regular, muri <0.3 µm thick.
Dimensions: polar diameter 39 (42.9) 46 µm, SD 2.9, equatorial diameter 25
(26.8) 28 µm, SD 1.5, polar/equatorial 1.6, n=4.
Comparisons: Arecipites Wodehouse, 1933 emend. Nichols, et al., 1973
accommodates monosulcate grains, tectate with colpi tapered (Jansonius and
Hill, 1976, card 166). Psilamonocolpites amazonicus Hoorn, 1993 is psilate
and columellae indistinct. Arecipites regio (Van der Hammen & Garcia, 1966)
Jaramillo & Dilcher, 2001 has colpi reaching the poles and slightly marginate.
Retimonocolpites claris Sarmiento, 1992 is semitectate and colpi rounded.
Arecipites? polaris n. sp.
Plate 3, Figs. 3, 4
Diagnosis: monocolpate, prolate, mid-sized (20-24 µm), micropitted, tectate,
colpi almost reaching the poles, borders straight, ends pointed, isopolar.
Specimens: Holotype AM27-29, EF: X55 1/3, pl. 3, figs. 3,4, paratype AM27-
29, EF: Q45 4
Type locality: Well 1AS-27-AM
Etymology: After the rounded polar area of the grain.
Description: Monad, bilateral, isopolar, elliptic; monocolpate, colpi long, ends
pointed, borders straight, colpi 18 µm long, CEi 0.75; tectate, exine 1 µm
thick, columellae indistinct; sculpture micropitted, lumina 0.5 µm wide, densely
distributed. Dimensions: polar diameter 20 (22) 24 µm, SD 2.8, equatorial
diameter 14 (14.5) 15 µm, SD 0.7, polar/equatorial 1.5, n=2.
Comparisons: Arecipites perfectus n. sp. is larger (39-46 µm) and colpi
shorter. Psilamonocolpites nanus Hoorn, 1993 and Psilamonocolpites
amazonicus Hoorn, 1993 are psilate.
Genus Bombacacidites Couper, 1960
Bombacacidites araracuarensis Hoorn, 1994
Plate 3, Figs. 5, 6
Diagnosis: Tricolporate, reticulate, triangular-obtuse-convex, mid-sized (25-39
µm), semitectate, Bombacacidites-type, pluricolumellate, nexine scabrate,
homobrochate, lumina wide, evenly distributed over entire grain.
Specimens: AM27-4, EF: S64 3 pl. 3, figs. 5, 6, AM27-22, EF: V39 3.
Description: Monad, radial, isopolar, triangular-obtuse-convex; tricolporate,
ectocolpi 16 µm wide, CEi 0.61, colpi costate, costae 1.5 µm wide, 2 µm thick,
pointed ends, endopores costate, costae 1.5 µm wide, lalongate; semitectate,
exine 2 µm thick, nexine 0.5 µm thick, columellae 1 µm thick, distinct, 1 µm
wide, 2-3 µm apart, densely scabrate, columellae increases towards muri,
tectum 0.5 µm thick; sculpture reticulate, homobrochate, lumina 3-4 µm wide,
3-4 µm long, muri 1 µm wide, pluricolumellate. Dimensions: equatorial length
25 (32) 39 µm, SD 9.9; equatorial width 26 (31) 36 µm, SD 7.1; equatorial
diameter length/width 1, n=2.
Natural affinities: Ceiba petandra, Malvaceae.
Bombacacidites fossulatus n. sp.
Plate 3, Figs. 14,15,16
Diagnosis: Tricolporate, triangular-obtuse-convex, mid-sized (29-44µm),
fossulate, colpi short, straight, semitectate, Bombacacidites-type fossulate.
Specimens: Holotype AM27-3, EF: R26 2/4 pl. 3, figs. 15,16, paratype: AM27-
17, EF: V54 3, pl. 3, figs. 14, AM27-25, EF: V25 4
Type locality: Well 1AS-27-AM
Etymology: After the fossulate sculpturing.
Description: Monad, radial, isopolar, triangular-obtuse-convex; tricolporate,
colporus intersubangular, colpi short, straight, pointed to rounded ends, colpi
10 µm long, CEi 0.27, costate, costae 2.0 µm wide, 1 µm thick, costae
surrounding the entire margin of the colpi; pores indistinct; semitectate, exine
1.8 µm thick, nexine 0.4 µm thick, columellae 1 µm thick, columellae 1 µm
wide, distinct, <1 µm apart, regularly distributed, tectum 0.4 µm thick;
sculpture fossulate, fossulae uniform at the apocolpia resembling a labyrinth,
lumina 1µm wide, 10-12 µm long, muri 1 µm wide, simplicolumellate,
gradually decreasing to foveolate towards interangular mesocolpia area,
foveos, <0.5 µm wide, circular. Dimensions: equatorial length 29 (35.8) 44
µm, SD 5.1; equatorial width 28 (36.8) 47 µm, SD 6.5; equatorial diameter
length/width 1, n=6.
Comparisons: Bombacacidites protofoveoreticulatus (Jaramillo & Dilcher,
2001) has both costae (3 µm) and muri (1.5 µm) thicker; foveo-fossulate is
uniformly distributed over entire grain.
Intraspecific variability: Grains with colpi without costae also were observed.
Bombacacidites nacimientoensis Anderson, 1960 Elsik, 1968
Plate 3, Figs. 17,18
Diagnosis: Tricolporate, triangular-obtuse-straight, mid-sized (52 µm),
reticulate, heterobrochate, tectate, simplicolumellate.
Specimens: AM27-8, EF: J 47 2 pl. 3, figs. 17,18
Description: Monad, radial, isopolar, triangular-obtuse-straight, corners
rounded; tricolporate, colpi 20 µ m long, CEi 0.52, marginate, margo 2 µm
thick, pores 2 µm wide, 2 µm high, costate, costae 2 µm wide; semitectate,
exine 2 µm thick, nexine 0.4 µm thick, columellae 1.2 µm thick, distinct,
tectum 0.4 µm thick; sculpture reticulate, lumina 1 µm wide, varying shape,
heterobrochate, simplicolumellate, lumina decreasing towards mesocolpia,
muri 0.5 µm thick, where becomes micropitted. Dimensions: equatorial length
52 µm; equatorial width 52 µm; equatorial diameter length/width 1, n=1.
Comparisons: Bombacacidites nacimentoensis Anderson, 1960 Elsik 1968 is
described as pluricolumellate. Every specimen observed here are
simplicolumellate. Some grains described in Jaramillo and Dilcher (2001) are
also simplicolumellate. Bombacacidites gonzalezii (Jaramillo and Dilcher,
2001) becomes psilate at mesocolpia. Bombacacidites ciriloensis (Muller et al.
1987) is multicolumellate and homobrochate.
Bombacacidites simpliciriloensis n. sp.
Plate 3, Figs. 7, 8, 9
Diagnosis: Tricolpate, triangular-obtuse-convex, mid-sized (41-49µm),
reticulate, simplicolumellate, semitectate, Bombacacidites-type, lumina
decreasing towards apocolpia area.
Specimens: Holotype AM27-5, EF: M51 1 pl. 3, figs. 7,8,9, paratype AM27-12,
EF: O25 1.
Type locality: Well 1AS-27-AM
Etymology: After the similarity with Bombacacidites ciriloensis Muller, et al.,
1987.
Description: Monad, radial, isopolar, triangular-obtuse-convex; tricolpate, colpi
short, simple, straight, pointed to rounded ends, colpi 18 µm long, CEi 0.36;
semitectate, exine 1.5 µm thick, nexine 0.5 µm thick, columellae distinct, 1 µm
thick, 1.5 µm wide, 1 µm apart, regularly distributed, tectum 0.5 µm thick;
sculpture reticulate, heterobrochate, lumina 1 µm wide in the apocolpia,
polygonal, gradually increasing towards mesocolpia, lumina 2-3 µm wide, 3-5
µm long, muri 0.8 µm, simplicolumellate. Dimensions: equatorial length 41
(45) 49 µm, SD 5.7; equatorial width 41 (46.5) 52, SD 7.8; equatorial diameter
length/width 1, n=2.
Comparisons: Bombacacidites ciriloensis Muller, et al., 1987 is
pluricolumellate.
Intraspecific variability: the presence of colpi marginate, margo 2 µm wide.
Bombacacidites zuatensis Lorente, 1986
Plate 3, Fig. 13
1993 Bombacacidites muinaneorum Hoorn, p. 302, pl. 2, fig. 19
Diagnosis: Tricolporate, triangular-obtuse-straight, mid-sized (20 µm),
reticulate, heterobrochate, becoming psilate in the mesocolpia, semitectate,
constriction in angular area.
Specimens: AM27-15, EF: G32 2 pl. 3, fig. 13, 27-20, EF: U36 2
Description: Monad, radial, isopolar, triangular-obtuse-straight; tricolporate,
brevicolporate 2 µm wide, colpi costate, costae 1 µm wide, 2 µm thick; pores
1 µm wide, pores 0.5 µm high, pores indistinct; semitectate, exine very thin,
0.7 µm thick, nexine 0.2 µm thick, columellae 0.3 µm thick, distinct, 0.5 µm
wide, 1 µm apart, tectum 0.2 µm thick; sculpture reticulate, heterobrochate,
lumina 0.5µm wide, decreasing abruptly towards angular mesocolpia area,
where becomes psilate, the angular psilate area is constricted, circular to
elongated, muri 0.3 µm thick, simplicolumellate. Dimensions: equatorial length
20 (25.3) 36 µm, SD 9.2; equatorial width 19 (26) 39 µm, SD 11.3; equatorial
diameter length/width 1, n=3.
Comparisons: We saw both holotypes (Bombacacidites zuatensis and
Bombacacidites muinaneorum) and they are the same grain, just a variation in
the angular area where a constriction was observed.
Bombacacidites sp.1
Plate 3, Figs. 10, 11, 12
Diagnosis: Tricolpate, circular, mid-sized (25-30 µm), foveoreticulate,
semitectate.
Specimens: AM27-23, EF: R36 3/4 pl. 3, figs. 10, 11, 12
Description: Monad, radial, circular; tricolpate, colpi very short, colpi 10 µm
long, CEi 0.4, simple, borders straight, ends pointed; semitectate, exine 1 µm
thick, nexine 0.3 µm thick, columellae distinct, 0.5 µm high, 1 µm apart,
tectum 0.2 µm thick; sculpture foveo-reticulate, lumina 0.5 µm wide, 0.5 µm
apart, slightly elongated to polygonal, homobrochate, foveos restricted to
apocolpia area, muri 0.5 µm wide. Dimensions: equatorial length 25 (27.5) 30
µm, SD 3.5; equatorial width 26 (28) 30 µm, SD 2.8; equatorial diameter
length/width 1, n=2.
Comparisons: Retibrevitricolpites retibolus Leidelmeyer, 1966 is semitectate.
Retibrevitricolpites triangulatus Van Hoeken-Klinkenberg, 1966 is triangular-
acute-convex. Bombacacidites sp. 1 (Jaramillo and Dilcher, 2001) is brevicolpi
costate.
Genus Byttneripollis KONZALOVA 1976
Byttneripollis ruedae n. sp.
Plate 3, Figs. 21,22
Diagnosis: Triporate, triangular-obtuse-convex, mid-sized (19 µm), reticulate,
muri undulating, semitectate, ectopores highly protruding, endopores costate.
Specimens: Holotype AM27-19, EF: M28 4 pl. 3, figs 21,22
Type locality: 1AS-27-AM
Etymology: In honor to D. Milton Rueda.
Description: Monad, radial, isopolar, triangular-obtuse-convex; triporate,
ectopores simple, protruding, 2 µm high, endopores costate, costae 3 µm
thick, 3 µm wide, atrium is present; semitectate, exine 1 µm thick, nexine 0.3
µm thick, columellae distinct, 0.5 µm thick, tectum 0.2 µm thick; sculpture
reticulate, lumina 0.5-1 µm wide, elongated to polygonal, heterobrochate, muri
undulating, 0.5 µm wide. Dimensions: equatorial length 19 µm; equatorial
width 18 µm; equatorial diameter length/width 1.1, n=1.
Comparisons: Byttneripollis coronarius KONZALOVA 1976 is larger (35 µm)
and has pores bigger (5 µm).
Botanical affinities: Byttneria, Ayennia-Malvaceae
Genus Cichoreacidites Sah, 1967
Cichoreacidites longispinosus Lorente, 1986 n. comb.
Plate 3, Figs. 26,27,28
1986 Fenestrites longispinosus Lorente p. 180, pl. 15, figs.1, 2
Diagnosis: Tricolporate, circular, mid-sized (22 µm), fenestrate, echinate,
spinae with perforations at the base, tectate.
Specimens: AM27-19, EF: G41 4 pl. 3, figs. 26,27,28
Description: Monad, radial, isopolar, circular; tricolporate, colpi seems like
simple, pores indistinct; tectate, thin exine, exine 0.6 µm thick, nexine 0.2 µm
thick, columellae 0.2 µm thick, distinct, columellae increases at the base of
the spines, tectum 0.2 µ m thick; sculpture fenestrate-echinate, lacunae 3-4
µm wide, circular to elongated, lophae 2 µm wide, spines 3-4 µm high, 3 µm
apart, conical, sometimes join at the top with ridges, every single spine has
one perforation in the base, perforation distinct. Dimensions: polar diameter
22 µm, equatorial diameter 19 µm, polar/equatorial 1.2, n=1; equatorial length
16 (20.3) 26 µm, SD 4.4; equatorial width 15 (20.3) 26 µm, SD 4.5; equatorial
diameter length/width 1, n=6.
Comparisons: Fenestrites Van der Hammen, 1956 is illegitimate and later
synonym of Crepis paludosa M., because the type species was based on the
recent pollen. Germeraad, et al., 1968 tried legitimate the genus, but the
lectogenotype also was based on Crepis Jansonius&Hills, 1976 card 1012.
Cichoreacidites Sah, 1967 accommodates tricolporate and grains with
fenestrae and echinae on the ridges Jansonius&Hills, 1976 card 470.
Variation: In some grains ridges join most of the spines.
Genus Cistacearumpollenites Nagy, 1969
Cistacearumpollenites rotundiporus n. sp.
Plate 3, Figs. 19,20
Diagnosis: Tricolporate, prolate, mid-sized (21-24µm), reticulate, semitectate.
Specimens: Holotype AM27-19, EF: S37 2 pl. 3, figs. 19,20, paratype: AM27-
19, EF: Q41 2
Type locality: Well 1AS-27-AM
Etymology: After the pores shape.
Description: Monad, radial, isopolar, prolate; tricolporate, colpi mid-sized,
simple, borders slightly convex, ends rounded, colpi 15 µm long, CPi 0.6,
pores slightly costate, costae 1 µm wide, pores 2 µm wide, pores 2 µm high,
circular; semitectate, exine 1 µm thick, nexine 0.4 µm thick, columellae 0.4 µm
high, 0.5-1 µm apart, distinct, tectum 0.2 µm thick; sculpture reticulate, lumina
0.5 µm wide, polygonal, densely distributed, muri 0.5 µm wide. Dimensions:
polar diameter 21 (22.5) 24 µm, SD 2.1, equatorial diameter 15 (17.5) 20 µm,
SD 3.5, polar/equatorial 1.3, n=2; Equatorial length 20 µm; equatorial width 20
µm; equatorial diameter length/width 1, n=1.
Comparisons: Cistacearumpollenites Nagy, 1969 accommodates tricolporate
pollen grains with rounded pores Jansonius&Hills, 1976, card 497.
Retitricolporites porisconspectus Hoorn, 1994 has pores bigger (5µm) and it
has operculum. Rhoipites hispidus (Van der Hammen and Wymstra, 1964)
Jaramillo and Dilcher, 2001 has colpi costate. Retitricolporites
santaisabelensis (Hoorn, 1994) has pores lalongate.
Intraspecific variability: In the ornamentation, some shows a reticulate pattern,
lumina 1 µm, heterobrochate, with lumina decreasing towards colpi.
Genus Clavainaperturites Van der Hammen&Wymstra, 1964
Clavainaperturites microclavatus Hoorn, 1994
Plate 3, Fig. 29
Diagnosis: Inaperturate, circular, mid-sized (20-23µm), clavate, intectate,
sometimes folded, thick exine.
Specimens: AM27-21, EF: X62 4 pl. 3, fig. 29
Description: Monad, radial, isopolar, circular; inaperturate; intectate, exine 1
µm thick; sculpture clavate, clavae 1 µm high, 0.3 µm thick, 0.3 µm wide,
circular in plain view, 0.5 µm apart, densely distributed over entire grain.
Sometimes, the grains are folded, showing a pentagonal fold in one side of
the grain. Dimensions: equatorial length 20 (21) 23 µm, SD 1.7; equatorial
width 18 (20.3) 23 µm, SD 2.5; equatorial diameter length/width 1, n=3.
Genus Corsinipollenites Nakoman, 1965
Corsinipollenites collaris n. sp.
Plate 3, Figs. 32,33
Diagnosis: Triporate, triangular-obtuse-convex, mid-sized (37µm), pores
circular, protruding, psilate, atectate, with a collar thickening.
Specimens: Holotype AM27-15, EF: X 30 4 pl. 3, figs. 32, 33
Type locality: Well 1AS-27-AM
Etymology: After the pores thickness resembling a collar.
Description: Monad, radial, anisopolar, on proximal area there is a Y mark, on
distal area the viscid threads are present, triangular-obtuse-convex; triporate,
endopores annulate, annuli with 2 µm wide, 2 µm thick, pores 6 µm wide,
pores 6 µm long, circular, highly protruding, at the base of the protruding there
is a collar-like thickening surrounding the base of the pore, resembling a
Normapollis structure; atectate, exine 1 µm thick; sculpture psilate.
Dimensions: equatorial length 37 µm; equatorial width 30 µm; equatorial
diameter length/width 1.2, n=1.
Comparisons: Corsinipollenites undulatus Gonzalez, 1967 Jaramillo&Dilcher,
2001 has rugulate undulating. Corsinipollenites psilatus Jaramillo&Dilcher,
2001 lacks the collar structure. Psilabrevitricolporites triangularis (Van der
Hammen & Wymstra, 1964) Jaramillo & Dilcher 2001 is tectate and the costae
thicker (5 µm).
Corsinipollenites oculusnoctis Thiergart, 1940 Nakoman, 1965
Plate 3, Figs. 23,24 and 25
Diagnosis: Triporate, triangular-obtuse-convex, mid-sized (33-38 µm), pores
lolongate, costate.
Specimens: AM27-26, EF: E65 2 pl. 3, figs. 23,24, tetrads: AM27-26, EF: R64
4, pl 3, fig. 25
Description: Monad, radial, anisopolar, triangular-obtuse-convex; triporate,
ecto and endopores coinciding, endopores costate, costae 2-3 µm wide, 2 µm
thick, pores 3-5 µm wide, 3-5 µm long, lolongate, highly protruding; grains
showing a fold resembling a Y mark on apocolpia area; tectate, exine 1 µm
thick, nexine 0.3 µm thick, columellae 0.4 µm high, columellae indistinct,
tectum 0.3 µm thick; sculpture psilate. Often tetrads are found, tetrads in
tetrahedral arrangement. Dimensions: equatorial length 33 (35.3) 38 µm, SD
2.5; equatorial width 28 (33.3) 40 µm, SD 6.1; equatorial diameter
length/width 1.1, n=3.
Corsinipollenites scabratus n. sp.
Plate 3, Figs. 30, 31
Diagnosis: Triporate, triangular-obtuse-convex, mid-sized (35-39 µm), pores
circular, protruding, costate and marginate, scabrate-verrucate, intectate, thick
exine
Specimens: Holotype AM27-15, EF: H35 2 pl. 3, figs. 30,31
Type locality: Well 1AS-27-AM
Etymology: After the ornamentation of the grain.
Description: Monad, radial, anisopolar, one of the poles has a distinct Y mark,
the another side does not have a fold, triangular-obtuse-convex; triporate,
ecto and endopores coinciding, pores costate and marginate, margo 2 µm
wide, 3 µm thick, produced by a thin of the exine around the pores, pores 3
µm wide, pores 3 µm long, circular, highly protruding; intectate, exine 2 µm
thick, exine decreases to 1.5 µm towards pores; sculpture scabrate, 0.5 µm
wide, 0.5 µm apart, densely distributed over entire grain, verrucae isolated,
randomly placed in over entire grain. Dimensions: equatorial length 35 (37)
39, SD 2.8; equatorial width 33; equatorial diameter length/width 1.1, n=2.
Comparisons: Corsinipollenites undulatus Gonzalez, 1967
JARAMILLO&DILCHER, 2001 is rugulate. Corsinipollenites oculusnoctis
Thiergart, 1940 Nakoman, 1965 is psilate.
Genus Cricotriporites Leidelmeyer, 1966
Cricotriporites sp. 1
Plate 4, Figs. 1,2
Diagnosis: Triporate, elliptic, mid-sized (25 µm), psilate-infrascabrate,
atectate.
Specimens: AM27-29, EF: L49 2/4 pl. 4, figs. 1,2
Description: Monad, radial, isopolar, elliptic; triporate, pores annulate, annulus
produced by thickening of the exine, 1-2 µm wide, 1-2 µm thick, pores 2 µm
wide, pores 2 µm long, circular; atectate, exine 0.5 µm thick, nexine 0.5 µm
thick; sculpture psilate-infrascabrate, densely distributed over entire grain.
Dimensions: equatorial length 25 µm; equatorial width 20 µm; equatorial
diameter length/width 1.3, n=1.
Comparisons: Cricotriporites Leidelmeyer, 1966 accommodates triporate
grains with psilate sculpture, pores annulate/costate and a circular shape
Jansonius&Hills, 1976 card 655. Cricotriporites minutiporus Muller, 1968
JARAMILLO&DILCHER, 2001 has pores bigger (3-5 µm).
Genus Crotonoideaepollenites Rao&Ramanujam, 1982
Crotonoideaepollenites reticulatus n. sp.
Plate 4, Figs. 3,4
Diagnosis: Inaperturate, circular, mid-sized (42-48 µm), clavate-reticulate,
intectate, crotonoid pattern.
Specimens: Holotype AM19-1, EF: J33 3 pl. 4, figs. 3,4, paratype AM19-1,
EF: T55 ½
Type locality: Well 1AS-19-AM
Etymology: After the croton pattern associate with reticulate ornamentation.
Description: Monad, radial, isopolar, circular; inaperturate; intectate, exine,
exine 1 µm thick; sculpture clavate, clavae 3 µ m high, the apices of clavae
has 1 µm wide, 1 µm apart, showing croton pattern, the nexine is reticulate,
the clavae are organized in a line on the top of the reticulum, lumina 1 µm
wide, polygonal, muri 0.5-1 µm wide. Dimensions: equatorial length 42 (45) 48
µm, SD 4.2; equatorial width 48 µm; equatorial diameter length/width 0.9,
n=2.
Comparisons: Crotonoidaepollenites Rao&Ramanujam, 1982 accommodates
inaperturate grains with crotonoid pattern Jansonius&Hills, 1976, card 4222.
Crototricolpites annemariae Leidelmeyer, 1966 is tricolpate.
Inaperturopollenites microclavatus (Regali et al. 1974) is tectate and larger
(80µm).
Intraspecific variation: thickness of the muri.
Genus Crototricolpites Leidelmeyer, 1966
Crototricolpites finitus n. sp.
Plate 4, Figs. 5, 6, 7, 8, 9
Diagnosis: Tricolpate, circular, prolate, mid-sized (27 µm), clavate with croton-
pattern only distinct in some areas of the grain, intectate, thick exine, internal
body.
Specimens: Holotype AM27-25, EF: C22 2 pl. 4, figs. 8, 9; paratype AM19-4,
Q37 1 pl. 4, figs. 5,6,7;
Type locality: Well 1AS-27-AM and 1AS-19-AM
Etymology: due to the presence of the thin clavae.
Description: Monad, radial, isopolar, circular, prolate; tricolpate, colpi long,
intruding, simple, borders straight, ends rounded, colpi 24 µm long, CEi 0.72;
intectate, exine 2 µm thick, nexine 2 µm thick; sculpture clavate, clavae 1 µm
high, 0.5-1 µm apart, densely distributed, 0.5 µm wide, usually present distinct
croton pattern, rounded to triangular in plain view, clavae increasing towards
colpi aperture, with a distinct inner body, psilate that has exine 0.5 µm thick.
Dimensions: polar diameter 27 µm, equatorial diameter 22 µm,
polar/equatorial 1.2, n=1; Equatorial length 33 µm, equatorial width 33 µm,
equatorial diameter length/width 1, n=1.
Comparisons: Crototricolpites annemariae Leidelmeyer, 1966 is bigger (48
µm) and has exine thinner (0.7 µm). Crototricolpites protoannemariae
JARAMILLO&DILCHER, 2001 has exine thinner (1 µm wide) and clave wider
(1 µm wide).
Intraspecific variation: in some grains the inner body are absente.
Genus Ctenolophonidites Van Hoeken-Klinkenberg, 1966
Ctenolophonidites suigeneris n. sp.
Plate 4, Figs. 10,11,12
Diagnosis: Stephanocolpate, circular, mid-sized (25-39 µm), psilate, atectate,
two ringlike are surrounding the colpi.
Specimens: Holotype AM27-24, EF: N58 4 pl. 4, figs. 10, 11, 12, paratypes:
AM27-15, EF: S37 3; AM27-7, EF: W65 4.
Type locality: Well 1AS-27-AM
Etymology: After the unnusual sculpture.
Description: Monad, radial, anisopolar, circular; stephanocolpate, 4 brevicolpi,
colpi 5 µm long, CEi 0.2, indistinct, simple, colpi lie by 2 short ridges, ridges 1
µm wide, 1 µm thick, 4 µm long, 1 µm apart, the small ridge is surrounded by
a double ring-ridge, 7 µm wide, 1 µm thick, 0.5 µm apart from another ridge,
15 µm long, the double-ring is also present on the apocolpia; atectate, thin
exine, exine 0.5 µm thick, thickening 1 µm thick in the ridges; surface inter-
ridge psilate. Dimensions: equatorial length 25 (32) 39 µm, SD 7; equatorial
width 20 (24.3) 31; equatorial diameter length/width 1.3, n=3.
Comparisons: Ctenolophonidites Van Hoeken-Klinkenberg, 1966
accommodates stephanocolpate grains. Ctenolophonidites costatus Van
Hoeken-Klinkenberg, 1964 Van Hoeken-Klinkenberg, 1966 has colpi costate
and the ridge is one ring. Ctenolophonidites lisamae (Van der Hammen &
Garcia, 1966) Germeraad et al. 1968 is scabrate and colpi costate.
Verrustephanocolpites rugulatus (Jaramillo and Dilcher, 2001) is rugulate.
Natural Affinities: Geissospermum, Apocynaceae.
Genus Dicolpopollenites Pierce, 1961
Dicolpopollenites obtusipolus n. sp.
Plate 4, Figs. 13,14,15,16
Diagnosis: Dicolpate, prolate, mid-sized (32-40 µm), reticulate to micropitted,
tectate, colpi long, borders straight, slightly tapered.
Specimens: Holotype AM27-28, EF: S36 2 pl. 4, figs. 15,16, 27-19, EF: P38 ½
pl. 4, figs. 13,14.
Etymology: After the shape of the grain.
Type locality: Well 1AS-27-AM
Description: Monad, radial, isopolar, prolate; dicolpate, colpi long, constricted
in equatorial area, colpi 30 µm long, CPi 0.86, borders straight, ends rounded,
marginate, margo 2 µm wide, margo produced by decreasing of the lumina
towards colpi; tectate, exine 2 µm thick, nexine 0.5 µm thick, columellae 1 µm
thick, distinct, tectum 0.5 µm thick; sculpture reticulate-micropitted, lumina 0.5
µm wide, rounded, densely distributed over entire grain, muri 0.5-1 µm thick.
Dimensions: polar diameter 32 (36.3) 40 µm, SD 3.3, polar diameter 16 (20.8)
25 µm, SD 3.8, polar/equatorial 1.8, n=4.
Genus Echiperiporites Van der Hammen & Wymstra 1964
Echiperiporites estelae Germeraad et al. 1968
Plate 4, Figs. 17, 18, 19
Diagnosis: Pantoporate, circular, mid-sized (42 µm), echinate, spines taller
than another specimens described here, tectate.
Specimens: AM27-28, EF: F25 4 pl. 4, figs. 17, 18, 19
Description: Monad, radial, isopolar, circular; pantoporate, ectopores simple,
endopores costate, costae with 2 µm thick, 10 pores, pores 3 µm wide, pores
3 µm high, circular; tectate, exine 2 µm thick, nexine 1 µm thick, columellae
0.8 µm thick, columellae increases towards echinae, tips distinct, rounded, <
0.4 µm wide, tectum 0.2 µm thick; sculpture echinate, spines 2 µm high, 2 µm
wide, conical, 3 µm apart, interspines surface showing tips. Dimensions:
equatorial length 42 µm; equatorial width 33 (40.5) 48 µm, SD 10.6; equatorial
diameter length/width 1.1, n=2.
Echiperiporites jutaiensis n. sp.
Plate 4, Figs. 20, 21
Diagnosis: Pantoporate, circular, mid-sized (28-30 µm), ecto/endopores
coinciding, endopores costate, echinate, tectate, nexine very thick, 7-11
pores.
Specimens: Holotype AM27-24, EF: E57 2 pl. 4, figs. 20, 21
Type locality: Well 1AS-27-AM
Etymology: After the Brazilian river name, where the well 1AS-27-AM was
drilled.
Description: Monad, radial, isopolar, circular; pantoporate, ecto/endopores
coinciding, endopores costate, costae 3 µ m wide, 1 µm thick, 7-11 pores,
pores 1.5 µm wide, pores 1.5 µ m high, circular; tectate, exine 3.5 µm thick,
nexine very thick, 3 µm thick, columellae 0.3 µm thick, indistinct, tectum 0.2
µm thick, the tectum above the costae lacks spines; sculpture echinate,
echinae 1-2 µm high, 1 µm wide, 2-3 µm apart, conical. Dimensions:
equatorial length 28 (29) 30 µm, SD 1.4; equatorial width 28 (28.5) 29 µm, SD
0.7; equatorial diameter length/width 1, n=2.
Comparisons: Echiperiporites estelae GERMERAAD, ET AL., 1968 has
spines longer (4-7µm) and exine thinner (1.6 µm). Echiperiporites akanthos
VAN DER HAMMEN&WYMSTRA, 1964 has pore marginate. Echiperiporites
sp. 1 Jaramillo&Dilcher, 2001 is bigger (90 µm) and spines smaller.
Intraspecific variability: sometimes gemmae also are observed together
echinae.
Echiperiporites intectatus n. sp.
Plate 4, Figs. 26, 27
Diagnosis: Pantoporate, circular, pores annulate (3 µm), protruding, echinate,
the spines could be in cluster or sparsely distributed usually near to pores,
intectate.
Specimens: Holotype AM27-13, EF: S27 pl. 4, figs 26, 27
Type locality: Well 1AS-27-AM
Etymology: After of the unusual intectate pattern in Echiperiporites.
Description: Monad, radial, isopolar, circular; pantoporate, pores annulate,
annuli 2-3 µm wide, 2 µm thick, 11-18 pores are present, pores 2 µm wide,
pores 2 µm high, circular, protruding; intectate, exine 1 µm thick; sculpture
echinate, spines 1-2 µm high, 1 µm wide, sub-conical, slightly constricted in
the base, showing two patterns in the distributions: 1) big spines organized in
cluster, densely arranged with a distribution in patches, 1 µm apart, usually
present near to pores, 2) small spines sparsely distributed, 3-4 µm apart,
surface interspines slightly scabrate, scabrate 1 µm wide, < 0.5 µm high, 0.5
µm apart. Dimensions: equatorial length 25 (30.7) 37 µm, SD 6; equatorial
width 22 (29) 35 µm, SD 6.6; equatorial diameter length/width 1.1, n=3.
Comparisons: Echiperiporites estelae (Germeraad et al., 1968) is tectate.
Psilaperiporites multiporus Hoorn, 1994 is psilate.
Echiperiporites lophatus n. sp.
Plate 4, Figs. 22, 23
Diagnosis: Pantoporate, echinate, circular, tectate, columellae very high at the
spine base, 30 pores, large, ornamentation resembling an echinolophate
pattern.
Specimens: Holotype AM27-7, EF: S24 pl. 4, figs. 22, 23
Type locality: Well 1AS-27-AM
Etymology: After the ornamentation of the grain.
Description: Monad, radial, isopolar, circular; pantoporate, endopores simple,
30 pores, pores 3 µm wide, pores 3 µm high, circular; tectate, exine 2.7 µm
thick, nexine very thick, 2 µm thick, columellae 0.5 µm thick, distinct,
columellae and tectum restricted to the bridge, resembling an echinolophate
pattern, columellae increases in the base of echinae reaching 5 µm high, 0.5
µm wide, 0.5 µm apart, tectum 0.2 µm thick; sculpture echinate-lophate,
spines very high, 8-10 µm high, 3 µm wide, 5 µm apart, conical, spines are
restricted to the bridge surrounded to the pores, lophae 3 µm wide, polygonal,
pluricolumellate, lacuna 6 µm wide, polygonal, in the middle of the lacuna
lacks sexine. Dimensions: equatorial length 42 µm; equatorial width 33 (40.5)
48 µm, SD 10.6; equatorial diameter length/width 1.1, n=2.
Comparisons: Echiperiporites estelae GERMERAAD, ET AL., 1968 has pores
annulate. Echiperiporites akanthos VAN DER HAMMEN&WYMSTRA, 1964
has pores marginate. Echiperiporites sp. 1 Jaramillo&Dilcher, 2001 is bigger
(90 µ m).
Genus Foveotricolporites Pierce 1961
Foveotricolporites lenticuloides n. sp.
Plate 4, Figs. 39, 40, 41, 42
Diagnosis: Tricolporate, prolate, mid-sized (34-36 µm), foveolate, tectate,
pores in lens shape.
Specimens: Holotype AM27-22, EFW39 ½ pl. 4, figs 39, 40; 27-60, EF: V23 1,
paratype AM27-22, EF: W56 pl. 4, figs. 41, 42
Type locality: Well 1AS-27-AM
Etymology: After the pores shape.
Description: Monad, radial, isopolar, prolate; tricolporate, colpi long, colpi 29
µm long, CPi 0.8, simple, borders slightly convex, ends pointed, pores simple,
lalongate, 10 µm wide, 3 µm high, lens shaped; tectate, exine 1.5 µm thick,
nexine 0.5 µm thick, columellae 0.5 µm thick, indistinct, tectum 0.5 µm thick;
sculpture foveolate, lumina 0.5 µ m wide, elongated, densely distributed, muri
0.5 µm thick. Dimensions: polar diameter 28 (32.7) 36 µm, SD 4.2, equatorial
diameter 20 (22.3) 24 µm, SD 2.1, polar/equatorial 1.5, n=3.
Comparisons: Foveotricolporites caldensis Gonzalez, 1967 has exine thicker
(2 µm) and colpi costate. Foveotricolporites marginatus Gonzalez, 1967 has
colpi marginatus. Foveotricolporites florschutzi Van der Hammen, 1954 van
der Hammen and Wymstra 1964 is smaller (18 µm).
Foveotricolporites pseudodubiosus n. sp.
Plate 4, Fig. 31
Diagnosis: Tricolporate, triangular-obtuse-convex to circular, mid-sized (18-25
µm), foveolate, semitectate.
Specimens: Holotype AM27-15, EF: W 26 4 pl. 4, fig. 31
Description: Monad, radial, isopolar, triangular-obtuse-convex to circular;
tricolporate, ectocolpi simple, short, 16 µm long, CEi 0.72, endopores costate,
costae 2-3 µm thick, very distinct, pores lalongate, pores 1 µm wide, pores 2
µm long; semitectate, exine 1 µm thick, nexine 0.3 µm thick, columellae 0.4
µm, tectum 0.3 µm thick; sculpture reticulate, lumina 0.5 µm wide, 0.5-2 µm
long, homobrochate, most of the lumina is rounded, but lumina elongated are
also found, densely distributed, multicolumellate, muri 1 µm wide.
Dimensions: equatorial length 18 (21.7) 25 µm; equatorial width 20 (23.7) 26
µm; equatorial diameter length/width 0.9, n=3.
Comparisons: Retitriporites poriscostatus Jaramillo&Dilcher, 2001 has pores
bigger (4µm). Retitriporites federicii Gonzalez, 1967 has larger lumina (3 µm).
Retitriporites dubiosus Gonzalez, 1967 is triporate. Foveotricolporites sp. 1
(Jaramillo & Dilcher, 2001) has endopores with fastigium.
Genus Glencopollis Pocknall&Mildenhall, 1984
Glencopollis curvimuratus n. sp.
Plate 4, Figs. 32, 33, 34
Diagnosis: pantoporate?, mid-sized (25-26µm), reticulate, polygonum-type,
circular, semitectate.
Specimens: Holotype AM19-8, EF: V43 1 pl. 4, figs. 32, 33, 34, paratype:
AM19-8, EF: J58 4
Type locality: Well 1AS-19-AM
Etymology: After the muri pattern.
Description: Monad, radial, isopolar, circular; pantoporate?; sometimes lighter
areas inside of the lumina is visible, resembling pores aperture; semitectate,
exine 3 µm thick, nexine 1 µ m thick, nexine echinate in the lumina, spines 0.5
µm wide, 0.5 µm high, 0.5 µm apart, columellae 1.5 µm thick, distinct, 1 µm
wide, 2-3 µm apart, tectum 0.5 µm thick, restricted to columellae; sculpture
reticulate, lumina 4 µm wide, homobrochate, elongated to circular, 14 lumina
are present on the proximal face, muri very thick, 2.0 µm wide, curvimurate,
pluricolumellate. Dimensions: equatorial length 25 (25.5) 26 µm, SD 0.7;
equatorial width 23 (23.5) 24 µm, SD 0.7; equatorial diameter length/width
1.1, n=2.
Comparisons: Glencopollis Pocknall&Mildenhall, 1984 accommodates with
affinity to the family Polygonaceae. Retitriporites mirabilis Regali, et al., 1974
has the same reticulum pattern but it is porate. Retipollenites confusus
Gonzalez, 1967 has reticulum that is not inserted in the exine.
Genus Gomphrenipollis Anzotegui&Cuadrado, 1996
Gomphrenipollis minimus n. sp.
Plate 4, Figs. 24, 25
Diagnosis: Inaperturate, fenestrate, circular, small-sized (14-17µm), 32
lacunas are present, semitectate.
Specimens: Holotype AM27-23, EF: Q39 ½ pl. 4, figs. 24, 25, paratype:
AM27-1, EF: U33 3
Type locality: Well 1AS-27-AM
Etymology: After the small size of the grain.
Description: Monad, radial, isopolar, circular; inaperturate; semitectate, thin
exine, exine 1.3 µm thick, nexine 0.2 µm thick, columellae 0.8 µm thick, 1 µm
wide, 5 µm apart, baculae also is present, 0.7 µm high, <0.5 µm wide, <0.5
µm apart, elongated in plain view, elongation is orthogonal to the lophae,
given a segmented aspect inside of the lophae, tectum 0.3 µm thick; the
columellae, tectum and nexine are restricted to the base of the lophae;
sculpture fenestrate, 27 lacunae are present showing a pattern 9-9-9, lacunae
4 µm wide, hexagonal to pentagonal, lophae 1 µm wide, 2 µm high.
Dimensions: equatorial length 14 Oboh-Ikuenobe, et al., 17 µm, SD 1.5;
equatorial width 15 (16) 17 µm, SD 1.5; equatorial diameter length/width 1,
n=3.
Comparisons: Gomphrenipollis Anzotegui&Cuadrado, 1996 accommodates
spherical, reticulate, periporate (Sic, Jansonius&Hills, 1976 card 5121) with
morphology similar to Gomphrena, Amaranthaceae. Jansonius and Hills,
1976 have suggested the invalid name due the absence of the Holotype
information, but they valided the genus name (Jansonius, Hills & Hartkopf-
Froder, 1988).
Natural affinities: Gomphrena, Amaranthaceae.
Genus Heterocolpites Nagy, 1969
Heterocolpites brevicolpatus n. sp.
Plate 4, Figs. 28, 29, 30
Diagnosis: Heterocolpate, sub-prolate, small-sized (16-17 µm), psilate,
tectate, pores indistinct, colpi constricted.
Specimens: Holotype AM19-1, EF: S19 3 pl. 4, figs. 28, 29, 30; paratype:
AM19-1, EF: S26 ½
Type locality: Well 1AS-19-AM
Etymology: After the colpi size.
Description: Monad, radial, isopolar, subprolate; heterocolpate, 6 aperture-3
colpi alternating with 3 colporus, colpi simple, colpi mid-sized, colpi 8 µm long,
CPi 0.5, borders straight, constricted, ends indistinct, pores very small,
simple, indistinct, pores 1.5 µm wide, pores 1.5 µm high, circular; tectate,
exine 1 µm thick, nexine 0.2 µm thick, columellae 0.4 µm high, indistinct,
tectum 0.4 µm thick; sculpture psilate. Dimensions: equatorial length 16 (16.5)
17 µm, SD 0.7, equatorial width 15 µm, equatorial diameter length/width 1.1,
n=2.
Comparisons: Heterocolpites paluster Gonzalez, 1967 has exine thicker (2
µm) and colpi marginate. Heterocolpites palaeocenica (Van der Hammen and
Garcia, 1966) has colpi longer, almost reaching the equator. Heterocolpites
incomptus Hoorn, 1993 has pores lalongate.
Heterocolpites rotundus Hoorn, 1993
Plate 4, Figs. 35, 36
Diagnosis: Heterocolpate, subprolate, mid-sized (18-21 µm), psilate, tectate,
pores circular.
Specimens: AM27-26, EF: F48 3 pl. 4, figs. 35, 36
Description: Monad, radial, isopolar, prolate; heterocolpate, 6 apertures, 3
colpi, 3 colporus, colpi alternating with colporus, colpi simple, colpi mid sized,
10 µm long, CPi 0.55, borders straight, ends indistinct, pores 3 µm wide, 3 µm
high, circular, simple; tectate, exine 1 µm thick, nexine 0.3 µm thick,
columellae 0.4 µm high, indistinct, tectum 0.3 µm thick; sculpture psilate.
Dimensions: polar diameter 18 (19) 21 µm, SD 1.7, equatorial diameter 12
(14) 15 µm, SD 1.7, polar/equatorial 1.4, n=3.
Heterocolpites verrucosus Hoorn, 1993
Plate 4, Figs. 37, 38
Diagnosis: Heterocolpate, circular, prolate, small-sized (16 µm), verrucate,
tectate.
Specimens: AM27-26, EF: L60 2 pl. 4, figs. 37,38: AM27-26, EF: E47 4
Description: Monad, radial, isopolar, circular, prolate; heterocolpate, 6
apertures, 3 colpi, 3 colporus, colpi alternating with a colporus, colpi mid-
sized, colpi 8 µm long, the colpi are often difficult to see, borders straight,
ends indistinct, pores 3 µm wide, pores 3 µm high, circular; tectate, exine 1.5
µm thick, nexine 0.5 µm thick, columellae 0.5 µ m high, indistinct, tectum 0.5
µm thick; sculpture verrucate, verrucae triangular to rounded, 0.5 µm high, 1
µm wide, densely distributed. Dimensions: polar diameter 14 (16.4) 19 µm,
SD 2.1, equatorial diameter 12 (14.4) 16 µm, polar/equatorial 1.2, n=5;
Equatorial length 15 µm; equatorial width 15 µm; equatorial diameter
length/width 1, n=1.
Genus Horniella Traverse, 1955
Horniella? caribbiensis Muller, et al., 1987 n. comb.
Plate 4, Figs. 43, 44
1986 Psilatricolporites caribbiensis Lorente, p. 194, pl. 20, fig. 4
1987 Psilatricolporites caribbiensis Muller et al., p. 48, pl. 4, figs. 9,10.
Diagnosis: Tricolporate, prolate, large-sized (48-52 µm), tectate, psilate.
Specimens: AM27-1, EF: S26 4 pl. 4, figs. 43, 44
Description: Monad, radial, isopolar, prolate, polar area is rounded;
tricolporate, colpi long, 45 µm long, CPi 0.86, intruding, borders straight, ends
reaching the polar area, pores slightly costate, costae 1-2 µm wide, 1 µm
high, pores 8 µm wide, pores 6 µm high, lalongate; tectate, exine 2 µm thick,
nexine 0.2 µm thick, columellae 1.4 µm thick, indistinct, 0.5 µm apart, 0.5 µm
wide, tectum 0.5 µm thick; sculpture psilate. Dimensions: polar diameter 48
(50) 52 µm, SD 2.8, equatorial diameter 36 (40) 44 µm, SD 5.7,
polar/equatorial 1.3, n=2.
Comparisons: Psilatricolporites Van der Hammen, 1956 ex Pierce, 1961 is an
obligate later synonym of Tricolporites Van der Hammen, 1954, because they
have the same type species Jansonius&Hills, 1976 card 2234). Horniella
TRAVERSE 1955 accommodates tricolporate, reticulate, prolate, and with thin
or lacing margo or colpicostate pollen grains (FREDERIKSEN 1983).
Jaramillo and Dilcher, 2001 have psilate grains in this genus. Retitricolpites
simplex Gonzalez, 1967 is very similar but it is reticulate.
Horniella morenoi n. sp.
Plate 5, Figs. 1, 2
Diagnosis: Tricolporate, prolate, mid-sized (21-28 µ m), micropitted,
heterobrochate, tectate, pores costate, lalongate, colpi simple.
Specimens: Holotype AM27-18, EF: U23 1 pl. 5, figs. 1, 2; paratype: AM27-9,
EF: Y25 4
Type locality: Well 1AS-27-AM
Etymology: in honor to Colombian palynologist, Enrique Moreno
Description: Monad, radial, isopolar, prolate; tricolporate, colpi mid-sized, colpi
15 µm long, CPi 0.5, borders straight, ends pointed, pores slightly costate,
costae 2 µm thick, pores 7 µm wide, pores 4 µm high, lalongate; tectate, exine
1 µm thick, nexine 0.3 µm thick, columellae 0.5 µm high, 0.5 µ m thick, 0.5 µm
wide, 1 µm apart, distinct, tectum 0.2 µm thick; sculpture micropitted, lumina
0.5 µm wide, circular, densely distributed, muri 0.3 µm wide. Dimensions:
polar diameter 21 (23.8) 28 µm, SD 2.6; equatorial diameter 15 (19) 25 µm,
SD 3.9; polar/equatorial 1.3, n=6.
Comparisons: Horniella sp. 3 (Jaramillo & Dilcher, 2001) has pores fastigiate.
Retitricolporites microreticulatus Herngreen, 1975 has pores simple.
Retitricolporites ellipticus VAN HOEKEN-KLINKENBERG, 1966 has colpi
costate.
Intraspecific variability: sculpture varies of micropitted to reticulate (lumina 1
µm wide), decreasing towards colpi.
Horniella? megaporata n. sp.
Plate 5, Figs. 11,12
Diagnosis: Tricolporate, prolate, small-sized (13 µm), psilate, tectate, large
pores, lalongate.
Specimens: Holotype: 27-75, EF: R52 ½ pl. 5, figs. 11,12
Type locality: Well 1AS-27-AM
Etymology: After the big size of the pores.
Description: Monad, radial, isopolar, prolate; tricolporate, colpi slightly costate,
costae < 1 µm thick, borders straight, ends rounded, almost reaching the
equator, colpi 9 µm long, CPi 0.69, pores simple, pores 5 µm wide, pores 2
µm high, lalongate, very large; tectate, exine 1.1 µm thick, nexine 0.3 µm
thick, columellae 0.3 µm high, indistinct, tectum 0.5 µm thick; sculpture
psilate. Dimensions: polar diameter 13 µm, equatorial diameter 11 µ m,
polar/equatorial 1.2, n=1.
Comparisons: Psilatricolporites garzonii Hoorn, 1993 has thicker exine, pores
slightly lalongate, smaller pores size. Psilatricolporites magniporatus Hoorn,
1993 has colpi costate. Psilatricolporites obesus Hoorn, 1993 and
Psilatricolporites silvaticus Hoorn, 1993 has exine thicker towards equator.
Genus Ilexpollenites Thiergart, 1938 Potonié, 1960
Ilexpollenites tropicalis n. sp.
Plate 5, Figs. 13, 14, 15
Diagnosis: Tricolporate, prolate, mid-sized (25 µm), clavate, clavae increasing
to polar area, intectate.
Specimens: Holotype AM27-24, EF: J58 ½ pl. 5, figs. 13,14,15, paratype
AM27-24, EF: G56 2
Type locality: Well 1AS-27-AM
Etymology: After the tropical zone that it is found.
Description: Monad, radial, isopolar, prolate, circular; tricolporate, colpi
costate, costae 2 µm wide, borders straight, ends rounded, gaping, colpi 16
µm long, CPi 0.64, pores simple, pores width indistinct, pores 3 µm long;
intectate, exine 4 µm thick; sculpture clavate, clavae 2-3 µm high, increasing
towards polar area, 1 µm wide, surface of clavae is scabrate. Dimensions:
polar diameter 25 µm, equatorial diameter 18 µm, polar/equatorial 1.4, n=1.
Equatorial length 30 µm, equatorial width 21 µm, equatorial diameter
length/width 1.4, n=1.
Comparisons: Ilexpollenites megagemmatus McIntyre, 1968 is gemmate and
has colpi almost indistinct. Ilexpollenites clifdenensis McIntyre, 1968) has
nexine and sexine of almost equal thickness. Ilexpollenites anguloclavatus
McIntyre, 1968) has clavae with angular top. Ilexpollenites verrucatus
Pocknall&Mildenhall, 1984 is tricolpate and verrucate/gemmate.
Genus Inaperturopollenites Pflug&Thomson, 1953 in
Thomson&Pflug, 1953
Inaperturopollenites solimoensis Leite, (in press)
Plate 5, Figs. 5,6
Diagnosis: Inaperturate, circular, mid-sized (32-40 µm), reticulate,
semitectate, simplicolumellate.
Specimens: AM27-29, EF: Q64 ¾ pl. 5, figs. 5, 6
Description: Monad, radial, isopolar, circular; inaperturate; semitectate, thin
exine, exine 1 µm thick, nexine 0.3 µm thick, columellae 0.4 µm thick, tectum
0.3 µm thick; sculpture reticulate, lumina1-2 µm wide, heterobrochate,
simplicolumellate, densely distributed, pentagonal, circular to oval, muri 0.5
µm wide. Dimensions: equatorial length 32 (36) 40 µm, SD 5.7; equatorial
width 29 µm; equatorial diameter length/width 1.2, n=2.
Comparisons: Inaperturopollenites curvimuratus Regali, et al., 1974 is tectate
and has curvimurate reticulum. Retipollenites sp.1 (Jaramillo & Dilcher, 2001)
has tectum thicker (4 µm), lumina wider (4-8 µm). Retipollenites confusus
Gonzalez, 1967 has lumina larger (1.5 µm) and exine thicker (3 µm).
Genus Ladakhipollenites Mathur&Jain, 1980
Ladakhipollenites floratus n. sp.
Plate 5, Figs. 3, 4
Diagnosis: Tricolpate, circular, mid-sized (23-26µm), colpi long, psilate,
tectate, colpi long, marginate, thin margo.
Specimens: Holotype AM27-23, EF: S 27 1/3 pl. 5, figs. 3,4
Type locality: Well 1AS-27-AM
Etymology: After the grain shape similarity with a flower.
Description: Monad, radial, isopolar, circular; tricolpate, colpi long, 24 µm
long, CEi 0.92, marginate, margo 2 µm wide, produced by a thinning of the
exine, borders straight, ends pointed; tectate, exine 1 µm thick, nexine 0.2 µm
thick, columellae 0.6 µm thick, indistinct, tectum 0.2 µ m thick, columellae
decreasing towards colpi, small polar area, 5 µm wide; sculpture psilate.
Dimensions: equatorial length 23 (24.5) 26 µm, SD 2.1; equatorial width 25
(26.5) 28, SD 2.1; equatorial diameter length/width 0.9, n=2.
Comparisons: Ladakhipollenites Mathur&Jain, 1980 accommodates tricolpate
grains with colpi long, exine psilate to faintly and obscurely sculpture
Jansonius&Hills, 1976. Psilatricolpites papilioniformis Regali, et al., 1974 is
faint striate. Ladakhipollenites sp. 1 (Jaramillo & Dilcher, 2001) has colpi
membrane gemmate. Psilatricolpites clarissimus Van der Hammen, 1954 van
der Hammen and Wymstra, 1964 has columellae distinct. Ladakhipollenites
simplex Gonzalez, 1967 Jaramillo and Dilcher, 2001 is highly prolate,
columellae distinct and thicker nexine (0.6 µm).
Ladakhipollenites rectangularis n. sp.
Plate 5, Figs. 7, 8, 9, 10
Diagnosis: Tricolpate, rectangular, mid-sized (25-26 µm), colpi mid-sized,
simple, psilate, tectate.
Specimens: Holotype AM27-21, EF: T 23 2 pl. 5, figs. 7,8; paratypes AM27-
21, EF: L33 2 and AM27-19, EF: X 37 1 pl. 5, figs 9,10
Type locality: Well 1AS-27-AM
Etymology: After the grain shape
Description: Monad, radial, isopolar, rectangular; tricolpate, colpi mid-sized,
colpi 17 µm long, CPi 0.68, simple, borders slightly convex, ends pointed;
tectate, exine 1.2 µm thick, nexine 0.2 µm thick, columellae 0.8 µm thick,
distinct, tectum 0.2 µm thick; sculpture psilate, few microechinae scattered
over entire grain, <0.4 µm wide and high, tips are visible, <0.3 µm wide.
Dimensions: equatorial length 25 (25.5) 26 µm, SD 0.7; equatorial width 17
(17.5) 18 µm, SD 0.7; equatorial diameter length/width 1.5, n=2.
Comparisons: Ladakhipollenites floratus n. sp. has colpi long and is psilate.
Psilatricolpites polaroides Gonzalez, 1967 has exine thicker in the polar area
(4 µm).
Genus Lakiapollis Venkatachala&Kar, 1969
Lakiapollis costatus n. sp.
Plate 5, Figs. 20, 21
Diagnosis: Tricolporate, triangular-obtuse-convex, mid-sized (17 µm), colpi
marginate and costate, psilate, tectate, columellae indistinct, tectum thick.
Specimens: Holotype AM27-28, EF: M54 2 pl. 5, figs. 20, 21; paratype AM27-
27, EF: Q56 2
Type locality: Well 1AS-27-AM
Etymology: After the costae of the colpi.
Description: Monad, radial, isopolar, triangular-obtuse-convex; tricolporate,
colpi short, 12 µm long, CEi 0.6, marginate, margo 2 µm wide, produced by
thinning of the nexine near to colpi, segmented, is not present in equatorial
area, colpi costate, costae 2 µm wide, 1 µm thick, distinct, absence of the
equatorial area, borders straight, ends rounded, colpi length 12 µm, pores
simple 4 µm wide, 2 µm high, lalongate, fastigiate; tectate, exine 2 µm thick,
nexine 1.5 µm thick, thick nexine, nexine decreases towards colpi, columellae
absent, tectum 0.5 µm thick; sculpture psilate. Dimensions: equatorial length
17 µm; equatorial width 18 (19) 20 µm, SD 1.4; equatorial diameter
length/width 0.9, n=2.
Comparisons: Lakiapollis Venkatachala&Kar, 1969 accommodates
brevicolpate, psilate or micropitted grains. Lakiapollis aff. ovatus
Venkatachala&Kar, 1969 has pores costate. Psilatricolporites costatus
Dueñas, 1980 has columellae distinct, colpi is not marginate. Psilatricolporites
marginatus Van der Kaars, 1983 colpi is not costate. Retitricolporites
ticuneorum Hoorn, 1993 is micropitted and colpi is not costate.
Genus Loranthacites Mchedlishvili in
Samoilovitch&Mchedlishvili, 1961
Loranthacites psilatus n. sp.
Plate 5, Figs. 16, 17
Diagnosis: Tricolpate, triangular-acute-straight, mid-sized (38 µm), psilate,
tectate, columellae digitate, colpi marginate.
Specimens: Holotype AM27-5, EF: M67 1 pl. 5, Figs. 16, 17
Etymology: After the colpi shape.
Description: Monad, radial, triangular-acute-straight; tricolpate, colpi very long,
38 µm long, CEi 1, marginate, margo 3 µm wide, produced by a thinning of
the columellae; tectate, exine 2 µm thick, nexine 0.2 µm thick, columellae 1.6
µm high, 0.5 µm wide, longitudinal distribution of the columellae resembling a
striate pattern, digitate, tectum 0.2 µm, near to colpi columellae disappear
where the tectum/sexine seems the same layer; sculpture psilate.
Dimensions: equatorial length 26 (34) 38 µm; equatorial width 30 (33.6) 37
µm; equatorial diameter length/width 1, n=5.
Comparisons: Loranthacites macrosolenoides Samoilovitch&Mchedlishvili,
1961 has reticulate/striate sculpture. Gothanipollis perplexus
Pocknall&Mildenhall, 1984 has sexine psilate at the apices varying from
scabrate to granulate in interapical areas.
Loranthacites sp. 1
Plate 5, Figs. 18, 19
Diagnosis: Syncolpate, triangular-acute-concave, mid-sized (28 µm), psilate,
tectate, with apocolpia field.
Specimens: AM27-9, EF: R 37 2, pl. 5 figs. 18,19
Description: Monad, radial, triangular-acute- concave; syncopate, apocolpia
filed is present, darker area in the apocolpia, borders straight, ends pointed;
tectate, exine 1 µm thick, nexine 0.3 µm thick, columellae 0.4 µm high,
distinct, 0.5 µm apart, tectum 0.3 µm; sculpture psilate. Dimensions:
equatorial length 25 (28.2) 31 µm; equatorial width 22 (30.8) 35 µm;
equatorial diameter length/width 1, n=4.
Comparisons: Loranthacites psilatus n. sp. has no apocolpia field, has colpi
marginate and columellae digitate.
Genus Malvacipolloides Anzotegui&Garalla, 1985/86
Malvacipolloides maristellae MULLER, ET AL., 1987 n. comb.
Plate 5, Figs. 25, 26
1986 Echitricolporites maristellae Lorente, p.190, pl. 19, figs. 2 and 3
1987 Echitricolporites maristellae Muller et al. p. 48, pl. 4, figs.11 and12
Diagnosis: Tricolporate, circular, mid-sized (30-39 µm), pores lalongate,
echinate, tectate, prominent spines present on the pores.
Specimens: AM27-2, EF: V38 ¾ pl. 5, figs. 25, 26
Description: Monad, radial, isopolar, circular; tricolporate, colpi short, 10 µm
long, CEi 0.26, simple, almost indistinct, pores 1 µm wide, 2-3 µm long,
costate, costae well developed, 3 µm wide, 2 µm thick; tectate, thin exine,
exine 1 µm thick, nexine 0.5 µm thick, columellae 0.5 µm thick, distinct,
tectum 0.5 µm thick, exine increasing to 2 µm thick towards spines base;
sculpture echinate, spinae 2-3 µm long, 3 µm wide, 3-5 µm apart, conical,
spinae higher near to aperture, reaching 4 µm long, the exine is denser and
darker at the base of the spines, interechinae surface micropitted.
Dimensions: equatorial length 30 (35.7) 39 µm, SD 4.9; equatorial width 28
(36.3) 42, SD 7.4; equatorial diameter length/width 1, n=3.
Comparisons: Echitricolporites Van der Hammen, 1956 Germeraad, et al.,
1968 is invalidate name because was based on recent pollen of Baccharis
tricuneata (L.f). Germeraad, et al., 1968 tried validate Echitricolporites but
also was an illegitimate name because designated a fossil species as type
species as proposed by Van der Hammen, 1956. Malvacipolloides
ANZOTEGUI&GARALLA, 1985/86 accommodates tricolporate, tectate and
echinate grains.
Malvacipolloides sp. 1
Plate 5, Figs. 22, 23, 24
Diagnosis: Brevitricolporate, circular, mid-sized (27 µm), pores lalongate,
echinate, tectate.
Specimens: AM19-3, EF: U29 2/4 pl. 5, figs. 22, 23, 24
Description: Monad, radial, isopolar, circular; tricolporate, colpi short, 10 µm
long, CEi 0.37, borders straight, ends rounded, slightly costate, costae 2 µm
wide, 0.5 µm thick, pores simple, pores 2 µm wide, 1 µm high, lalongate,
indistinct; tectate, exine 1.5 µm thick, nexine 0.3 µm thick, columellae 0.9 µm
thick, distinct, tectum 0.3 µ m thick; sculpture echinate, spinae 3 µm long, 2
µm wide, 2-3 µm apart, conical in plain view, interspines surface micropitted.
Dimensions: equatorial length 27 µm; equatorial width 26 µm; equatorial
diameter length/width 1, n=1.
Comparisons: Malvacipolloides maristellae Muller, et al., 1987 n. comb. has
spines protruding near to aperture. Echiperiporites estelae (Germeraad et al.
1968) is periporate.
Malvacipolloides sp. 2
Plate 5, Figs. 27, 28
Diagnosis: Tricolporate, triangular-obtuse-convex, mid-sized (38 µm),
echinate, tectate.
Specimens: AM27-21, EF: X41 2 pl. 5, figs. 27, 28
Description: Monad, radial, isopolar, triangular-obtuse-convex; tricolporate,
colpi long, 20 µm long, CEi 0.6, simple, pores indistinct; tectate, exine 1.5 µm
thick, nexine 0.4 µm thick, columellae 0.9 µm thick, very thin, dense, 0.1 µm
apart, densely packed, tectum 0.2 µm thick; sculpture echinate, spines 3-5 µm
high, 2-3 µm wide, 3 µm apart, spines are cylindrical of the base, 4µm wide,
tapered at the apices, 1 µm high, interspines region is micropitted, lumina
<0.5 wide. Dimensions: equatorial length 33 µm; equatorial width 33 µm;
equatorial diameter length/width 1, n=1.
Comparisons: Brevitricolporites macroexinatus Jaramillo&Dilcher, 2001 has
endopores costatus. Brevitricolporites microechinatus Jaramillo&Dilcher, 2001
has pores annulate.
Malvacipolloides? sp. 3
Plate 5, Figs. 43, 44
Diagnosis: Tricolporate, circular, prolate, mid-sized (32 µm), microechinate,
tectate.
Specimens: AM27-22, EF: Y70 1 pl. 5, figs. 43, 44
Description: Monad, radial, isopolar, circular, prolate; tricolporate, colpi long,
colpi 16 µm long, CEi 0.5, simple, borders straight, ends pointed, endopores
simple, lalongate; tectate, exine 0.8 µm thick, nexine 0.2 µm thick, columellae
0.4 µm thick, indistinct, tectum 0.2 µm thick, sculpture microechinate, <0.5 µm
high and wide, well distributed, 1 µm apart, interspines region is psilate.
Dimensions: equatorial length 32 µm, equatorial width 28 µm, equatorial
diameter length/width 1.1, n=1.
Comparisons: Brevitricolpites microechinatus Jaramillo&Dilcher, 2001 is
intectate, Brevitricolpites variabilis Gonzalez, 1967 is clavate to gemmate.
Genus Margocolporites Ramanujam, 1966 ex Srivastava, 1969
emend. Pocknall&Mildenhall, 1984
Margocolporites fastigiatus n. sp.
Plate 5, Figs. 33, 34, 35, 36
Diagnosis: Margotricolporate, circular, mid-sized (22-26µm), colpi marginate,
pores indistinct, psilate, micropitted-scabrate, tectate (ENGLOBAR PSILATE-
MICROP).
Specimens: Holotype, EF: AM27-30 V31 2 pl. 5, figs. 33, 34; paratype: AM27-
30, EF: U 32 4, AM27-22, EF: X54 2 pl. 5, figs. 35, 36;
Etymology: After the presence of the fastigium
Type locality: Well 1AS-27-AM
Description: Monad, radial, isopolar, small polar area 6 µm, circular;
tricolporate, colpi mid-sized, colpi 14 µm long, CEi 0.6, ectocolpi marginate,
margo 2 µm wide, margo produced by a thinning of the exine to 1 µm around
the colpi, borders straight, ends pointed, endopores simple, fastigiate, 8 µm
wide, 2 µm high, lalongate; tectate, exine 1.5 µm thick, nexine 0.5 µm thick,
columellae indistinct, columellae disappear near to colpi, tectum 1 µm thick;
sculpture micropitted, lumina <0.5 µm wide, circular, heterobrochate, lumina
decreases towards colpi becoming the margo psilate. Dimensions: Polar
diameter 28 µm, equatorial diameter 22 µm, polar/equatorial 1.3, n=1;
Equatorial length 22 (25.2) 28 µm, SD 2.2, equatorial width 17 (24.2) 27 µm,
SD 4.1, equatorial diameter length/width 1, n=5.
Comparisons: Siltaria hammeni n. sp. has colpi costate.
Margocolporites pseudodemicolpatus n. sp.
Plate 5, Figs. 39, 40
Diagnosis: Brevitricolporate, triangular-obtuse-straight, mid-sized (28-36µ),
psilate, atectate, colpi is surrounded by a thinning of the exine.
Specimens: Holotype AM27-26, EF: G38 1/3 pl. 5, figs. 39, 40; paratype:
AM27-26, EF: D59 1
Type locality: Well 1AS-27-AM
Etymology: After the pseudo shape of the colpi
Description: Monad, radial, isopolar, triangular-obtuse-straight; tricolporate,
colpi costate, costae 2 µm wide, 2 µm thick, borders straight, ends pointed,
colpi 10 µm long, CEi 0.28, endopores costate, costae 2 µm thick, pores 2 µm
wide, 1 µm high, lalongate; atectate, exine 1 µm thick, the grain shows a
unusually thinner of the exine in the interangular area, the exine becomes thin
between the colpi in the semi angular area, there are two thin of the exine 1)
between each colpi, the thinner in the apocolpia area produced a feature
resembling a apocolpia field, 2) 2 endocolpi surrounding each brevicolpi;
sculpture psilate. Dimensions: Equatorial length 28 (32.8) 36 µm, SD 3.6,
equatorial width 28 (34) 49 µm, SD 5, equatorial diameter length/width 1, n=4.
Comparisons: Margocolporites Ramanujam, 1966 ex Srivastava, 1969
emend. Pocknall&Mildenhall, 1984 accommodates Margocolporate grains
from psilate to reticulate sculpture. Psilate grains have not been reported in
any species of Margocolporites, may be this specimen is the same specimen
Margocolporites rauvolfii described by Salard-Cheboldaeff, 1978. Similar to
Ctenolophonidites Van Hoeken-Klinkenberg, 1966 but this genus is
characterized by a thickening of the exine. Margocolporites scabratus
Pocknall&Mildenhall, 1984 is psilate to scabrate and amb roundly triangular.
Natural affinities: Raufolvia, Apocynaceae.
Margocolporites sp. 1
Plate 5, Figs. 41, 42
Diagnosis: Tricolpate, circular, mid-sized (28 µm), reticulate, heterobrochate,
semitectate, colpi marginate
Specimens: AM27-26, EF: H56 4 pl. 5, figs. 41, and 42
Description: Monad, radial, circular; tricolpate, colpi long, marginate, margo 4
µm wide, produced by a decreasing of the reticulum, borders straight, ends
pointed, colpi 26 µm long; semitectate, exine 1 µm thick, nexine 0.3 µm thick,
columellae 0.5 µm high, distinct, tectum 0.2 µm thick; sculpture reticulate,
heterobrochate, lumina gradually decreasing from interangular area to colpi,
0.5-2.0 µm wide, elongated, muri 0.5 µm wide, pluricolumellate. Dimensions:
equatorial length 28 µm, equatorial width 28, equatorial diameter length/width
1, n=1.
Comparisons: Margocolporites vanwijhei GERMERAAD, ET AL., 1968 has
colpi costate and marginate.
Genus Meliapollis Sah&Kar, 1970
Meliapollis? sp. 1
Plate 5, Figs. 29, 30
Diagnosis: Stephanocolporate, circular to quadrangular, mid-sized (22 µm),
psilate, atectate.
Specimens: AM27-27, EF: M60 4/3 pl. 5, figs. 29, 30
Description: Monad, radial, isopolar, circular to quadrangular;
stephanocolporate, colpi simple, 5-colporate, colpi mid-sized, colpi 12 µm
long, CEi 0.54, borders straight, ends rounded, large polar area of 12 µm
wide, pores costate, costae 1 µm thick, pores 1 µm wide, pores 1 µm high,
circular; atectate, exine 1 µm thick; sculpture psilate. Dimensions: equatorial
length 22 µm, equatorial width 22 µm, equatorial diameter length/width 1.1,
n=1.
Comparisons: Tetracolporites Couper, 1953 emend. Pocknall&Mildenhall,
1984 has spherical to polygonal shape and colpi indistinct Jansonius&Hills,
1976 card 4348. Psilastephanocolporites Leidelmeyer, 1966 has 8-10 furrows
and pores Jansonius&Hills, 1976 card 2229). Meliapollis Sah&Kar, 1970
accommodates grains with colpi simple, pores costate, psilate and tectate.
Here, we accept this genus despite of the grain is atectate. Tetracolporites
psilatus Jaramillo&Dilcher, 2001 has ectocolpi marginate, is tectate, larger
(30-50 µm). Psilastephanocolporites variabilis (Regali et al., 1974) has colpi
costate. Psilastephanocolporites globulus Van Hoeken-Klinkenberg, 1966 has
colpi costate, is smaller (16 µm) and is intectate.
Genus Monocolpopollenites Pflug&Thomson, 1953 in
Thomson&Pflug, 1953 emend. Nichols, et al., 1973
Monocolpopollenites sp. 1
Plate 5, Figs. 37, 38
Diagnosis: monocolpate, circular, mid-sized (22 µm), micropitted, tectate,
colpi short, flared.
Specimens: AM27-33, EF: O27 4 pl. 5, figs. 37, 38
Description: Monad, bilateral, isopolar, circular; monocolpate, colpi short, colpi
16 µm long, CEi 0.72, ends flared, borders straight; tectate, exine 0.5 µm
thick; sculpture micropitted, lumina < 0.5 µm. Dimensions: polar diameter 22
µm, equatorial diameter 22 µm, polar/equatorial 1, n=1.
Comparisons: Monocolpopollenites ovatus (Jaramillo & Dilcher, 2001) is
larger (32-60µm). Arecipites polaris n. sp. is prolate and colpi pointed.
Genus Multiporopollenites Pflug&Thomson, 1953 in
Thomson&Pflug, 1953
Multiporopollenites crassinexinatus n. sp.
Plate 6, Figs. 1, 2
Diagnosis: Pantoporate, circular, mid-sized (23 µm), pores irregular,
micropitted, tectate, nexine very thick.
Specimens: Holotype AM27-23, EF: N40 3 pl. 6, figs. 1, 2
Type locality: Well 1AS-27-AM
Description: Monad, radial, isopolar, circular; pantoporate, ecto/endopores
coinciding, pores 1 µm wide, pores 1 µm long, circular to elongated, 24 pores
are presents; tectate, exine 3 µm thick, nexine very thick, 2 µm thick,
columellae 0.8 µm thick, distinct, 0.5 µm wide, 0.5 µm apart, tectum 0.2 µm
thick; sculpture micropitted, lumina 0.5 µm wide, circular, homobrochate,
densely distributed, muri 0.5 µm wide. Dimensions: equatorial length 23 µm;
equatorial width 22 µm; equatorial diameter length/width 1, n=1.
Comparisons: Psilaperiporites minimus REGALI, ET AL., 1974 is psilate and
has more pores (40-50 pores). Multiporopollenites pauciporatus
JARAMILLO&DILCHER, 2001 has pores annulate. Psilaperiporites robustus
(Regali et al. 1974) has 80 pores.
Genus Paleosantalaceapites Biswas 1962 ex Dutta & Sah
(1970)
Paleosantalaceapites sp. 1
Plate 6, Figs. 3, 4
Diagnosis: Tricolporate, prolate, mid-sized (24-35 µm), foveolate, tectate,
zonasulcate.
Specimens: Holotype AM27-18, EF: T41 3 pl. 6, figs. 3, 4
Description: Monad, radial, isopolar, area polar rounded, prolate; tricolporate,
colpi long, costate, costae 2 µm wide, 1 µm thick, borders straight, ends
indistinct, colpi 18 µm long, CPi 0.75, zonosulculate, simple 4 µm high;
tectate, exine 1.2 µm thick, nexine 0.5 µm thick, columellae 0.5 µm high, 0.5
µm apart, distinct, tectum 0.2 µm thick; sculpture foveolate, lumina 0.5 µm
wide, circular, muri 1 µm wide. Dimensions: Polar diameter 24 (29.6) 37 µm,
SD 5.1, equatorial diameter 15 (17.1) 23 µm, SD 3.0, Polar/equatorial 1.7,
n=7.
Comparisons: Paleosantalaceapites Biswas 1962 ex Dutta & Sah (1970)
accommodates tricolporate, longi or brevicolpate, zonosulculate pollen grains.
Paleosantalaceaepites distinctus (Jaramillo & Dilcher, 2001) has lumina
decreasing from pole to equator.
Genus Parsonsidites Couper 1960
Parsonsidites? brenacii n. sp.
Plate 6, Figs. 5, 6
Diagnosis: Pantoporate, mid-sized (16-21 µm), circular, psilate, tectate, 10
pores, thick tectum.
Specimens: Holotype AM27-20, EF: S37 3 pl. 6, figs. 5, 6
Type locality: Well 1AS-27-AM
Etymology: In honor to Patrick Brenac
Description: Monad, radial, isopolar, circular; pantoporate, pores simple, 10
pores are present, pores 2 µm wide, pores 2 µm high, circular; tectate, exine
3 µ m thick, nexine 0.5 µm thick, columellae 2 µm thick, distinct, 0.5 µm wide,
0.5-1 apart, tectum very thin, 0.5 µm thick; sculpture psilate, he tips of the
columellae are highly visible. Dimensions: equatorial length 16 (18.7) 21 µm,
SD 2.5; equatorial width 17 (19.3) 21 µ m, SD 2.1; equatorial diameter
length/width 1, n=3.
Comparisons: Multiporopollenites pauciporatus Jaramillo&Dilcher, 2001 is
micropitted.
Genus Proxapertites Van der Hammen, 1956
Proxapertites tertiaria Van der Hammen & Garcia 1966
Plate 6, Fig. 16
1987 Proxapertites magnus Muller et al., p. 37, Pl. 1, Fig. 11.
2001 Proxapertites magnus Jaramillo & Dilcher, p. 141, Pl. 14, Figs. 10, 11.
Diagnosis: zonosulcate, circular, big-sized (90 µm), foveolate, tectate.
Specimens: AM27-3, EF: R42 4 pl. 6, Fig. 16
Description: Monad, radial, anisopolar, triangular to circular, sulcus dividing
the grain in two unequal parts; zonosulcate; tectate, exine 3 µm thick, nexine
1 µm thick, columellae 1 µm high, tips very discernible, thick tectum, tectum 1
µm thick; sculpture foveolate, foveos 0.5 µm wide, distributed uniformly for
whole grain. Dimensions: equatorial length 90 µm, equatorial width 82 µm,
equatorial diameter length/width 1.1, n=1.
Comparisons: The difference between Proxapertites tertiaria (Van der
Hammen & Garcia, 1966) and Proxapertites magnus (Muller et al., 1987) is
based on size of the grain. However, intermediate sizes also were observed.
Genus Psilabrevicolpites van Hoeken-Klinkenberg, 1966
Psilabrevicolpites flexibilis van Hoeken-Klinkenberg, 1966
Plate 6, Figs. 11, 12, 13
Diagnosis: Tricolpate, brevicolpate, triangular-obtuse-concave, mid-sized (18
µm), psilate, tectate, colpi simple.
Specimens: AM27-28, EF: P28 1/2 pl. 6, figs. 11, 12, 13
Description: Monad, radial, isopolar, triangular-obtuse-concave; tricolpate,
colpi simple, brevicolpate, colpi 6 µm long, CEi 0.3, borders straight, ends
ragged irregular; tectate, exine 1.2 µm thick, nexine 0.3 µm thick, columellae
0.2 µm high, indistinct, tectum 0.7 µm thick, exine thickness uniform; sculpture
psilate. Dimensions: Equatorial length 18 µm, equatorial width 19 µm,
equatorial diameter 0.9, n=1.
Genus Psilabrevitricolporites Van der Kaars, 1983
Psilabrevitricolporites devriesi Lorente 1986 n. comb.
Plate 6, Figs. 7, 8, 9, 10
1986 Psilatricolporites devriesi Lorente et al. p.197, pl. 21, figs 1,2
Diagnosis: Tricolporate, brevicolpate, circular, mid-sized (22 µm), psilate,
tectate, colpi simple, colpi costate, thick exine.
Specimens: AM27-31, EF: X30 4 pl. 6, Figs. 7, 8, 9, 10
Biochronological range: UA 1
Description: Monad, radial, circular to triangular-obtuse-convex, oblate;
tricolporate, colpi costate, costae 2 µm wide, 2 µm thick, brevicolpi 10 µm
long, CEI, CPi borders straight, ends pointed, pores simple, pores 3 µm wide,
pore 3 µm high, circular; tectate, thick exine, exine 3 µm thick, sexine 1 µm
thick, columellae 1 µm high, distinct, tectum µm thick; sculpture psilate.
Dimensions: equatorial length 22 (22.5) 23 µm, SD 0.7; equatorial width 21
µm, equatorial diameter length/width 1.1, n=2; polar diameter 30 µm,
equatorial diameter 25 µm, polar/equatorial 1.2, n=1.
Psilabrevitricolporites sp. 1
Plate 6, Figs. 14, 15
Diagnosis: Tricolporate, circular, mid-sized (29 µm), psilate, tectate, pores
annulate.
Specimens: AM27-18, EF: R 25 4 pl. 6, figs. 14, 15
Type locality: Well 1AS-27-AM
Description: Monad, radial, isopolar, circular; brevicolporate, colpi 10 µm long,
CEi 0.34, slightly marginate, 1 µm wide, margo produced by a thinning of the
exine, pores costate, 1 µm wide, 1 µm thick, pores 2.5 µm wide, pores 2.2 µm
high, circular; tectate, exine 1 µm thick, nexine 0.2 µm thick, columellae 0.6
µm thick, indistinct, columellae decreasing towards pores, tectum 0.2 µm
thick; sculpture psilate. Dimensions: equatorial length 29 µm; equatorial width
26 µm; equatorial diameter length/width 1.1, n=1.
Comparisons: Psilabrevitricolporites devriesi Lorente, 1986 n. comb. has
pores costate and exine thicker (2 µm). Siltaria mariposa Leidelmeyer, 1966
Jaramillo and Dilcher, 2001 has longer colpi.
Genus Psilaperiporites Regali et al. 1974
Psilaperiporites sp. 1
Plate 6, Figs. 24, 25
Diagnosis: Pantoporate, circular, mid-sized (30 µm), pores costate, psilate,
tectate, 18 pores.
Specimens: Holotype 27-38, EF: W21 4/3 pl. 6, Figs. 24, 25
Description: Monad, radial, isopolar, circular; pantoporate, pores slightly
annulate, annulus 2 µm wide, highly distinct, 18 pores arranged in pairs, each
pores on each hemisphere is facing the another one, pores simple, pores 3
µm high, pores 3 µm wide, 7 µm apart, circular; atectate, exine 0.5 µm thick;
sculpture psilate. Dimensions: equatorial length 30 µm; equatorial width 25
µm; equatorial diameter length/width 1.2, n=1.
Comparisons: Psilaperiporites multiporus Hoorn, 1994 has pores that are not
arranged in pairs. Psilaperiporites robustus Regali, et al., 1974 has more
pores (60-64 pores).
Genus Psilastephanoporites Regali, et al., 1974 ex Hoorn, 1993
Psilastephanoporites herngreenii Hoorn 1993
Plate 6, Figs. 17, 18
Diagnosis: Stephanoporate, circular to quadrangular, mid-sized (µm), psilate,
atectate.
Specimens: AM27-27, EF: S55 1 pl. 6, figs. 17, 18
Description: Monad, radial, isopolar, circular to quadrangular; stephanoporate,
pores 7 µm wide, pores 7 µm long, circular, 4 pores costate, costae 5 µm
wide, 2 µm thick, protruding, granulate at the pores base; atectate, exine 0.5-
1 µm thick, increasing to 4 µm near to pores; sculpture psilate. Dimensions:
equatorial length 45 µm; equatorial width 40; equatorial diameter length/width
1.1, n=1.
Psilastephanoporites sp. 1
Plate 6, Figs. 26, 27, 28
Diagnosis: Stephanoporate, circular, mid-sized (22-31 µm), psilate, atectate.
Specimens: AM27-26, EF: E46 2 pl. 6, figs 26, 27, 28
Description: Monad, radial, isopolar, circular; stephanoporate, pores 3 µm
wide, pores 3 µm long, circular, 4 pores annulate, annulus 2.5 µm wide, 2 µm
thick, protruding, slightly granulate at the base; atectate, exine 0.5 µm thick;
sculpture psilate. Dimensions: equatorial length 22 (26.5) 31 µm, SD 6.4;
equatorial width 30 (33.5) 37 µm, SD 4.9; equatorial diameter length/width
0.8, n=2.
Comparisons Psilastephanoporites herngreenii Hoorn, 1993 has annuli of 8
µm thick. Psilastephanoporites stellatus Regali, et al., 1974 has 6 pores and
exine thicker.
Genus Retibrevitricolpites Van Hoeken-Klinkenberg, 1966
Retibrevitricolpites sp. 1
Plate 6, Figs. 19, 20
Diagnosis: Tricolporate, circular, mid-sized (23 µm), micropitted, tectate.
Specimens: AM27-24, EF: D45 4 pl. 6, figs. 19, 20
Description: Monad, radial, isopolar, circular; tricolporate, colpi short, simple,
borders straight, ends pointed, colpi 6 µm long, CEi 0.26, pores indistinct;
tectate, exine 1.0 µm thick, nexine 0.3 µm thick, columellae 0.4 µm thick,
indistinct, tectum 0.3 µm thick; sculpture micropitted, densely distributed, 0.5
µm wide, 0.5 µm apart. Dimensions: equatorial length 23 µm, equatorial width
20 µm, equatorial diameter length/width 1.2, n=1.
Comparisons: Retibrevitricolpites retibolus Leidelmeyer, 1966 and
Psilabrevicolporites sp. 1 (Jaramillo and Dilcher, 2001) have pores costate.
Genus Retibrevitricolporites Legoux 1978
Retibrevitricolporites yavarensis Hoorn 1993 n. comb.
Plate 6, Figs. 34, 35, 36, 37
1993 Retibrevitricolpites yavarensis Hoorn 1993
Diagnosis: Tricolporate, circular, mid-sized (20 µm), micropitted, tectate,
brevicolpate, colpi costate, pores simple.
Specimens: AM27-28, EF: T48 4 pl. 6, Figs. 34, 35, tetracolporate: AM27-23,
EF: T34 4, pl. 6, Figs. 36, 37
Description: Monad, radial, circular; tricolporate, colpi very short, colpi 10 µm
long, CEi 0.5, borders straight, ends pointed, colpi costate, costae 1.5 µm
wide, pores simple, lalongate, indistinct; tectate, exine 1 µm thick, nexine 0.3
µm thick, columellae 0.5 µm high, 0.5 µm apart, distinct, tectum 0.2 µm thick;
sculpture micropitted, lumina 0.5 µm wide, circular to elongate,
homobrochate, muri 0.5 µm wide. Dimensions: Equatorial length 20 µm,
equatorial width 20 µm, equatorial diameter 1, n=1.
Comparisons: The species was firstly described as tricolpate, but we saw the
holotype and it is tricolporate. Grain tetracolporate also were found.
Genus Retistephanocolpites Leidelmeyer, 1966 emend. Saxena,
1982
Retistephanocolpites circularis n. sp.
Plate 6, Figs. 31, 32, 33
Diagnosis: Stephanocolpate, circular, mid-sized (23-24 µm), reticulate,
tectate, 5 colpi, brevicolpate, colpi marginate, homobrochate.
Specimens: Holotype AM27-27, EF: G57 1/2 pl. 6, figs. 31, 32, 33, paratype
AM27-20, EF: W24 3
Type locality: Well 1AS-27-AM
Etymology: After the circular shape of the grain.
Description: Monad, radial, isopolar, circular; stephanocolpate, 5 colpi, colpi
marginate, margo produced by a thinning of the exine, 2 µm wide,
brevicolpate, colpi 8 µm long, CEi 0.26, borders straight, ends rounded;
tectate, exine 2 µm thick, nexine 0.5 µm thick, columellae 1 µm high, distinct,
0.5 µm thick, 1 µm apart, columellae decreases towards colpi, tectum 0.5 µm
thick; sculpture reticulate, lumina 0.5 µm wide, homobrochate, circular to
elongated, muri 0.5 µm wide. Dimensions: equatorial length 30 (32) 34 µm,
SD 2.8, equatorial width 25 (28) 31 µm, SD 4.2, polar/equatorial 1.2, n=2.
Comparisons: Retistephanocolpites Leidelmeyer, 1966 emend. Saxena, 1982
accommodates stephanocolpate grains with reticulate, foveoreticulate or
foveolate sculpture JANSONIUS&HILLS, 1976 card 4149.
Retistephanocolpites gracilis (Regali et al., 1974) has 6-8 colpi and colpi
shorter.
Genus Retistephanocolporites Van der Hammen & Wymstra
1964
Retistephanocolporites sp. 1
Plate 6, Figs. 21, 22, 23
Diagnosis: Stephanocolporate, prolate, mid-sized (19µm), micropitted, tectate,
colpi costate pores simple.
Specimens: AM27-7, EF: U24 2 pl. 6, figs. 21, 22, 23
Description: Monad, radial, isopolar, prolate; stephanocolporate, colpi mid-
sized, colpi 14 µm long, CPi 0.73, colpi costate, costae 1 µm thick, decreasing
from mesocolpia to apocolpia, borders straight, ends pointed, endopores
simple, pores 2 µm wide, pores 3 µm long, lolongate; tectate, exine 2 µm
thick, nexine 1 µm thick, columellae 0.5 µm high, distinct, tectum 0.5 µm thick;
sculpture micropitted, lumina 0.5 µm, homobrochate, circular, densely
distributed over entire grain, muri <0.2 µm wide. Dimensions: polar diameter
19 µm, equatorial diameter 14 µm, polar/equatorial 1.4, n=1.
Comparisons: Retistephanocolporites festivus Gonzalez, 1967 is larger (26-50
µm).
Genus Retitrescolpites Sah, 1967
Retitrescolpites? traversei n. sp.
Plate 6, Figs. 40, 41, 42, 43, 44
Diagnosis: Tricolporate, prolate, mid-sized (26-30µm), reticulate,
heterobrochate, simplicolumellate, semitectate, pores operculate.
Specimens: Holotype AM27-24, EF: J60 4 pl. 6, figs. 184, 185 and 186;
paratype AM27-21, EF: U26 1 pl. 6, figs. 40, 41
Type locality: Well 1AS-27-AM
Etymology: After the reticulum shape.
Description: Monad, radial, prolate; tricolporate, colpi long, colpi 22 µm long,
CPi 0.73, borders straight, ends pointed, marginate, margo 3 µ m wide, margo
produced by a drastic decreasing of the reticulum, pores simple, pores 2 µm
wide, pores 2 µm long, circular, operculate, operculum 1 µm wide, 1 µm long;
semitectate, exine 3.5 µm thick, nexine 1.5 µm thick, increasing to 1 µm
towards apocolpia area, columellae 1.5 µm high, distinct, tectum 0.5 µm thick,
restricted to columellae; sculpture reticulate, lumina 4-7 µm wide, polygonal,
simplicolumellate, heterobrochate, abruptly decreasing around colpi to 1 µm,
muri 1 µm wide. Dimensions: polar diameter 26 (28) 30 µ m, equatorial
diameter 18 (19) 20 µm polar/equatorial 1.5, n=2.
Comparisons: Retitrescolpites Sah, 1967 accommodates tricolpate-colporate
coarsely reticulate grains. Retitrescolpites magnus Gonzalez, 1967
Jaramillo&Dilcher, 2001 has regular lumina.
Natural affinity: Teliostachya, Acanthaceae
Retitrescolpites? sp. 1
Plate 6, Figs. 38, 39
Diagnosis: Tricolporate, circular, mid-sized (27 µm), coarsely reticulate,
semitectate and pores costate.
Specimens: 19-2, EF: N51 2/1 pl. 6, figs. 38, 39
Description: Monad, radial, circular; tricolporate, colpi long, simple, borders
straight, ends pointed, colpi intruding, small polar area, 7 µm wide, colpi 10
µm long, CEi 0.37, pores costate, costae 2 µm wide, 2 µ m thick, pores 2 µm
wide, pores 2 µm long, circular; semitectate, exine 4 µm thick, nexine 0.4 µm
thick, columellae 2.8 µm high, distinct, tectum 0.8 µm thick, decreasing to 2
µm towards aperture produced by decreasing of the columellae; sculpture
reticulate, heterobrochate, lumina of the mesocolpia 3 µm wide, elongated to
polygonal, decreasing gradually towards apocolpia where becomes
micropitted, muri 1.5 µm wide, curvimurate, pluricolumellate. Dimensions:
equatorial length 27 µm, equatorial width 26 µm, polar/equatorial 1, n=1.
Comparisons: Bombacacidites sp. 3 (Jaramillo and Dilcher, 2001) has pores
lalongate and foveoreticulate. Retibrevitricolpites retibolus Leidelmeyer, 1966
is brevicolpate. Retitrescolpites? irregularis (Van der Hammen and Wymstra,
1964) Jaramillo and Dilcher, 2001 is homobrochate.
Retitrescolpites sp. 2
Plate 6, Figs. 29, 30
Diagnosis: tricolpate, triangular-obtuse-convex, mid-sized (18-24 µm),
reticulate, semitectate, folded at the poles, resembling a trilete mark.
Specimens: 27-58, EF: V21 1/2 pl. 6, Figs. 29, 30, 27-92, EF: X63 2
Biochronological range: from UA 1 to UA 7.
Description: Monad, radial, isopolar, triangular-obtuse-convex; tricolpate, colpi
marginate, margo 2 µm wide, margo produced by decreasing of the lumina,
borders straight, ends pointed, colpi 8 µm long; semitectate, exine 1.2 µm
thick, nexine 0.2 µm thick, columellae 0.8 µm thick, tectum 0.2 µm thick;
sculpture reticulate, almost foveolate near to colpi, lumina 2 µm wide, lumina
irregular decreasing towards colpi, muri <0.5 µm wide. Dimensions: equatorial
length 18 (21) 24 µm, SD 3, equatorial width 12 (16.3) 22 µm, SD 5.1,
equatorial diameter length/width 1.3, n=3.
Comparisons: Retitricolpites marginatus Van Hoeken-Klinkenberg, 1966 has
lumina wider (3.5 µm), exine thicker (2.5µm) and larger (32 µm).
Genus Retitriporites Ramanujam, 1966
Retitriporites rotundus n. sp.
Plate 6, Figs. 45, 46, 47, 48
Diagnosis: Triporate, triangular-obtuse-convex, mid-sized (26-27µm), foveo-
reticulate, tectate, pores marginate and large.
Specimens: Holotype 27-22, EF: P52 ½ pl. 6, figs. 47, 48; paratypes: 27-20,
EF: U24 4, 27-18, EF: N40 ½ pl. 6, figs. 45, 46
Type locality: Well 1AS-27-AM
Etymology: After the grain shape.
Description: Monad, radial, isopolar, triangular-obtuse-convex; triporate,
ectopores and endopores coinciding, 10 µm wide, 3 µm long, marginate,
margo 3 µm wide, produced by decreased of lumina towards pores, pores
circular, pores 9 µm wide; tectate, exine 1-2 µm thick, exine 2 layered, inner
part 0.6-1.5 µm thick, straight, outer 0.5 µm thick, lighter color, columellae is
not present, tectum is present only in the muri of the reticulum; sculpture
foveo-reticulate, lumina decreasing towards pores, heterobrochate, 2-3 µm
wide, muri is reticulate with small lumina arranged in line parallels to the
borders of the muri, 1-2 µm wide, well distinct. Dimensions: equatorial length
20 (24.8) 27 µm, SD 3.2; equatorial width 20 (26) 29 µm, SD 4.2; equatorial
diameter length/width 1.0, n=4.
Comparisons: Retitriporites tilburgii Gonzalez, 1967 has lumina smaller (0.7
µm).
Variation: grains with triangular-acute-straight shape also were found.
Retitriporites sp. 1
Plate 7, Figs. 1, 2
Diagnosis: Triporate, triangular-obtuse-convex, mid-sized (28 µm), reticulate,
semitectate, endopores costate, muri curvimurate.
Specimens: 27-75, EF: K49 4/3 pl. 7, figs. 1, 2
Description: Monad, radial, isopolar, triangular-obtuse-convex; triporate,
endopores costate, costae 2-3 µm wide, 2 µm thick, pores lolongate, pores 1
µm wide, 2 µm long; semitectate, exine 3 µm thick, nexine 1 µm thick,
columellae 1.0 µm wide, 2 µm apart, well distinct, tectum 1.0 µm thick;
sculpture reticulate, lumina 2-5 µm wide, elongated, sinuous,
simplicolumellate, muri 1 µm wide, curvimurate. Dimensions: equatorial length
29 µm; equatorial width 29 µm; equatorial diameter length/width 1, n=1.
Comparisons Spirosyncolpites spiralis Gonzalez, 1967 is tricolpate and exine
thicker (9 µm). Retitriporites amplireticulatus (Jaramillo & Dilcher, 2001) has
lumina wider (6-8 µm) and pores indistinct. Retitriporites mirabilis (Regali et
al. 1974) is larger (80 µm). Retitriporites dubiosus Gonzalez, 1967 has lumina
smaller (0.8 µm). Retitriporites federicii Gonzalez, 1967 has annuli is larger (5
µm). Retitriporites simplex Van der Kaars, 1983 has lumina smaller (< 1 µm).
Genus Rhoipites Wodehouse, 1933
Rhoipites gigantiporus n. sp.
Plate 7, Figs. 3, 4, 5, 6
Diagnosis: Tricolporate, prolate, mid-sized (33-35 µm), reticulate, semitectate,
pores large, costate.
Specimens: Holotype 27-87, EF: L48 4 pl. 7, figs. 3, 4, paratype: 27-60, EF:
W25 2, 27-28, EF: G35 2/4 pl. 7, figs. 5, 6
Type locality: Well 1AS-27-AM
Etymology: After the pores size.
Description: Monad, radial, isopolar, prolate; tricolporate, colpi short, colpi 25
µm long, CPi 0.71, simple, borders straight, ends pointed, pores costate,
costae 1 µm wide, 0.5 µm thick, pores 7 µm wide, pores 6 µm long, lalongate;
semitectate, exine 2 µm thick, nexine 0.3 µm thick, columellae 1.4 µ m high,
0.5 µm wide, 1 µm apart, tectum 0.3 µm thick; sculpture reticulate,
homobrochate, lumina 1-2 µm wide, elongated to polygonal, muri 0.5 µm
wide, simplicolumellate. Dimensions: polar diameter 32 (34.3) 35 µm, SD 1.2,
equatorial diameter 16 (21.1) 25 µm, SD 2.8, polar/equatorial 1.6, n=8.
Comparisons: Retitricolporites wijmstrae Hoorn, 1994 colpicostate. Rhoipites
guianensis Van der Hammen&Wymstra, 1964 JARAMILLO&DILCHER, 2001
has lumina decreasing towards colpi. Retitricolpites wijningae (Hoorn, 1994) is
tricolpate.
Genus Rubipollis Mildenhal & Pocknall 1989
Rubipollis muellerae n. sp.
Plate 5, Figs. 31, 32
Diagnosis: Tricolporate, circular, mid-sized (21-28µm), reticulate,
heterobrochate, semitectate, endopores costate and colpi marginate.
Specimens: Holotype 27-112, EF: W26 ¾ pl. 5, figs 31, 32, paratype: 27-102,
EF: R17 2
Type locality: Well 1AS-27-AM
Etymology: In honor to the palynologist Jan Muller
Description: Monad, radial, isopolar, circular; tricolporate, colpi mid-sized,
marginate, margo 2 µm wide, margo produced by a thinning of the columellae
and decreasing of the lumina of the reticulum, colpi 20 µm long, CEi 0.71,
borders straight, ends pointed, apocolpia 4 µm wide, endopores costate,
costae 2 µm, pores 7 µ m wide, pores 4 µm high, lalongate; semitectate, exine
2 µm thick, nexine 0.5 µm thick, columellae 1 µm high, distinct, 1 µm wide, 0.5
µm apart, tectum 0.5 µm thick, sexine decreases towards pores where
becomes almost absent; sculpture reticulate, heterobrochate, lumina
polygonal, 2 µm wide decreasing to 0.5 µm wide near to colpi, muri 0.5 µm
wide, simplicolumellate. Dimensions: Equatorial length 21 (23.5) 28 µm, SD
3.8; equatorial width 15 (17.7) 22 µm, SD 3.8; equatorial diameter
length/width 1.4, n=3.
Comparisons: Rubipollis (Midenhall & Pocknall, 1989) accommodates
tricolporate grains with Rubiaceae’s pollen morphology. Margocolporites
vanwijhei GERMERAAD, ET AL., 1968 has colpicostate.
Genus Scabratricolpites (Van der Hammen) Gonzalez 1967
Scabratricolpites elongatus n. sp.
Plate 7, Figs. 46, 47
Diagnosis: Tricolpate, per-prolate, mid-sized (38 µm), scabrate, intectate,
thick exine.
Specimens: Holotype 27-15, EF: V41 4 pl. 7, figs. 46, 47, paratype 27-20, EF:
V31 1/2
Type locality: Well 1AS-27-AM
Etymology: After the pollen shape.
Description: Monad, radial, per-prolate; tricolpate, colpi long almost reaching
the equator, colpi 33 µm long, CPi 0.8, simple, borders straight, ends pointed;
intectate, exine 2 µm thick; sculpture scabrate, verrucae 0.5 µm high, 0.5 µm
wide, 0.5 µm apart, rounded to slightly elongated, regularly distributed over
entire grain. Dimensions: polar diameter 38 µm, equatorial width 9 (11) 13
µm, SD 2.8, polar/equatorial 3.6, n=2.
Comparisons: Scabratricolpites thomasi Sarmiento, 1992 and
Scabratricolpites tibialis Gonzalez, 1967 are tectate. Scabratricolpites
angelicus Sarmiento, 1992 has exine thinner (0.5 µm thick).
Genus Siltaria Traverse, 1955
Siltaria amygdalas n. sp.
Plate 7, Fig. 7
Diagnosis: Tricolporate, prolate, mid-sized (20-24 µm), micropitted, tectate,
pores circular, costate, colpi marginate.
Specimens: Holotype and paratypes: 27-98, EF: S48 pl. 7, figs. 7
Type locality: Well 1AS-27-AM
Etymology: After the shape of the grains.
Description: Monad, radial, isopolar, prolate, area polar pointed; tricolporate,
colpi long, colpi 19 µm long, reaching the equator, marginate, margo 2 µm
wide, borders straight, ends pointed, pores costate, costae 1 µm thick, pore 2
µm wide, pore 2 µm long, circular; tectate, exine 1.2 µm thick, nexine 0.2 µm
thick, columellae 0.8 µm high, 0.5 µm apart, distinct, tectum 0.2 µm thick;
sculpture micropitted, lumina <0.5 µm wide, circular, decreasing towards
colpi, regular, muri <0.3 µm wide. Dimensions: Polar diameter 20 (22.3) 24
µm, SD 1.7, equatorial diameter 14 Oboh-Ikuenobe, et al., 16 µm, SD 0.8,
polar/equatorial 1.5, n=4.
Comparisons: Siltaria sp.1 (Jaramillo & Dilcher, 2001) has colpi costate and
pores simple. Siltaria sp. 2 (Jaramillo & Dilcher, 2001) is spherical. Siltaria sp.
3 is fastigiate.
Siltaria hammeni n. sp.
Plate 7, Figs. 8, 9, 10, 11, 12
Diagnosis: Tricolporate, prolate, mid-sized (25-28 µm), micropitted, tectate.
Specimens: Holotype, UFP 40, EF: U35 ½ pl. 7, figs. 8, 9, 10 paratype 27-51,
EF: Y 29 2 pl. 7, figs. 11, 12, 27-98, EF: H22 2
Type locality: Well 1AS-27-AM
Etymology: In honor to Thomas Van der Hammen, a Dutch palynologist
Description: Monad, radial, isopolar, prolate; tricolporate, colpi costate, costae
3 µm wide, 1 µm thick, colpi long, colpi 25 µm long, CPi 0.89, borders straight,
ends pointed, pores simple, pores 4 µm wide, pores 2 µm long, lalongate;
tectate, exine 1 µm thick, nexine 0.3 µm thick, columellae 0.4 µm high,
indistinct, tectum 0.3 µm thick; sculpture micropitted, lumina <0.5 µm, wide,
circular, homobrochate, muri 0.3 µm wide. Dimensions: Polar diameter 25
(28) 31 µm, SD 2.2, equatorial diameter 13 (15.3) 16 µm, SD 1.1,
Polar/equatorial 1.8, n=7.
Siltaria mariposa Leidelmeyer, 1966 Jaramillo & Dilcher, 2001
Plate 7, Figs. 13, 14,15, 16, 17
Diagnosis: Tricolporate, circular, mid-sized (22-26µm), micropitted, tectate,
colpi costate.
Specimens: 27-27, EF: F38 3 pl. 7, Figs. 13, 14,15, 16, 17; 27-53, EF: V32 4
Description: Monad, radial, isopolar, circular; tricolporate, ectocolpi marginate,
thin margo, 2 µm wide, produced by a thinning of the columellae, borders
straight, ends pointed, ectocolpi short, 20 µm long, CEi 0.45, pores costate,
pores 2 µm wide, 1 µm thick, lalongate; tectate, exine 1 µm thick, thickness
slightly decreases towards colpi, nexine 0.2 µm thick, columellae 0.6 µm high,
distinct, tectum 0.2 µm thick; sculpture micropitted, lumina <0.3 µm wide,
circular, lumina decreases towards margo of the colpi, muri <0.3 µm wide.
Dimensions: Polar diameter 22 µm, equatorial diameter 22 µm,
polar/equatorial 1 µm, n=1; equatorial length 20 (23.7) 26 µm, SD 2.3,
equatorial width 21 (23.5) 26 µm, SD 1.8, equatorial diameter length/width 1,
n=6.
Comparisons: Margocolporites vanwijhei Germeraad, et al., 1968 is reticulate.
Margocolporites sp. 1 Jaramillo&Dilcher, 2001 2001 has two rings in the
pores. Margocolporites sp. 2 Jaramillo&Dilcher, 2001 is bigger (43-50 µm).
Margocolporites fastigiatus n. sp. is fatigiate.
Siltaria pseudosyncolpata n. sp.
Plate 7, Figs. 18, 19
Diagnosis: Tricolporate, circular, mid-sized (29 µm), colpi marginate, pores
costate, micropitted, tectate.
Specimens: Holotype 19-03, EF: W 36 1, pl. 7, figs. 18, 19; paratype 27-51,
EF: Q 32 4
Type localities: Well 1AS-19-AM and Well 1AS-27-AM
Etymology:
Description: Monad, radial, isopolar, circular; tricolporate, colpi long, colpi
marginate, margo produced by a thinning of the exine, margo 3 µm wide,
borders straight, ends pointed, colpi 15 µm long, CEi 0.5, pores slightly
protruding, costate, costae well developed, 1 µm wide, 3 µm thick, pores 3 µm
wide, pores 3 µm long, circular; tectate, exine 2 µm thick, nexine 0.5 µm thick,
columellae 1 µm high, decreasing to 0.5 µm near to colpi, tectum 0.5 µm
thick; sculpture micropitted, densely distributed over entire grain, lumina 0.5
µm wide, circular, muri 0.5 µm wide. Dimensions: Polar diameter 29 µm;
Equatorial diameter 29 µm; polar/equatorial 1, n=1; equatorial length 30 (31)
32 µm, SD 1.4; equatorial width 29 (29.5) 30 µm, SD 0.7; equatorial diameter
length/width 1.1, n=2.
Comparisons: Siltaria mariposa Leidelmeyer, 1966 Jaramillo and Dilcher,
2001 has colpi almost reaching the equator and pore with costae not very well
developed.
Siltaria santaisabelensis Hoorn, 1994 n. comb.
Plate 7, Figs. 20, 21, 22
Diagnosis: Tricolporate, prolate, mid-sized (19 µm), micropitted, tectate, colpi
and pores costate.
Specimens: 27-68, EF: H51 3 pl. 7, figs. 20, 21, 22
Description: Monad, radial, isopolar, prolate; tricolporate, colpi mid-sized, colpi
14 µm long, CPi 0.77, costate, costae 1 µm wide, 1 µm thick, costae
decreases from mesocolpia to apocolpia, borders straight, ends pointed,
pores 3 µm wide, pores 3 µm long, circular, pores costate, costae 1.5 µm
thick; tectate, exine 1 µm thick, nexine 0.2 µm thick, sculptural columellae 0.6
µm high, distinct, tectum 0.2 thick; sculpture micropitted, lumina 0.5 µm wide,
circular, homobrochate, densely distributed over entire grain, muri 0.5 µm
wide. Dimensions: polar diameter 19 µm, equatorial diameter 19 µm,
polar/equatorial 1, n=1.
Siltaria tectata n. sp.
Plate 7, Figs. 31, 32
Diagnosis: Tricolporate, prolate, mid-sized (25-31 µm), micropitted, tectate,
pores simple, tectum very thick.
Specimens: Holotype: 27-60, EF: T34 2 pl. 7, figs. 31, 32, paratype: 27-51,
EF: P32 ½
Type locality: Well 1AS-27-AM
Etymology: After the thickness of the tectum
Biochronological range: from UA 1 to UA 3
Description: Monad, radial, prolate; tricolporate, colpi costate, costae 1 µm
wide, 2 µm thick, colpi long, colpi 20 µm long, CPi 0.64, borders straight,
constricted, ends pointed, pores simple, pore 2 µm wide, pores 3 µm long,
lalongate; tectate, exine 2 µm thick, nexine 0.5 µ m thick, columellae 0.5 µm
high, indistinct, tectum very thick, 1 µm thick; sculpture micropitted, lumina 0.5
µm, circular, densely distributed over entire grain. Dimensions: Polar diameter
25 (27.5) 31 µm, SD 3; Equatorial diameter 19 (21.9) 25 µm, SD 2.2;
polar/equatorial 1.3, n=8; equatorial length 22 (23.5) 25 µm, SD 2.1,
equatorial width 15 (20) 25 µm, SD 7.1, equatorial diameter length/width 1.3,
n=2.
Comparisons: Foveotricolporites crassiexinus Van Hoeken-Klinkenberg, 1966
has pores costate. Retitricolporites caputoi Hoorn, 1993 has columellae
longer and distinct. Psilatricolporites crassoexinatus Hoorn, 1993 is psilate.
Siltaria sp. 1
Plate 7, Figs. 23, 24, 25
Diagnosis: Tricolporate, oblate, mid-sized (22 µm), psilate, tectate, columellae
organized in a reticulate pattern.
Specimens: Holotype: 27-65, EF: X34 4 pl. 7, figs. 23, 24, 25, paratype: 27-
112, EF: R61 2
Type locality: Well 1AS-27-AM
Biochronological range: from UA 2 to UA 7
Description: Monad, radial, isopolar, circular; tricolporate, colpi costate, costae
1 µm thick, decreasing to 0.5 µm from mesocolpia to apocolpia, borders
straight, ends pointed, colpi 15 µm long, CPi 0.68, pores 4 µm wide, pores 2
µm long, lalongate with lateral ends pointed-lens shaped; tectate, exine 1.5
µm thick, nexine 0.5 µm thick, columellae 0.5 µm high, 0.5 µm wide, 1 µm
apart, in plain view columellae shows highly distinct reticulate infratectum
pattern, tectum 0.5 µ m thick; sculpture psilate. Dimensions: polar diameter 12
(17) 22 µm, equatorial diameter 13 (17.5) 22 µm, polar/equatorial 1, n=2.
Comparisons: Psilatricolporites costatus Dueñas, 1980 has tectum thicker,
costae wider and thicker. Psilatricolporites normalis Gonzalez, 1967 is larger
(30 µm). Psilatricolporites cyamus (van der Hammen & Wymstra, 1964) has
colpi with a bridge. Psilatricolporites atalayensis Hoorn, 1993 is larger (24-31
µm), prolate, pores slightly lalongate.
Genus Striasyncolporites Germeraad, et al., 1968
Striasyncolporites anastomosatus n. sp.
Plate 7, Figs. 26, 27, 28, 29, 30
Diagnosis: Syncolporate, prolate, triangular-obtuse-convex, mid-sized (41µm),
striate, striation anastomosing, tectate.
Specimens: Holotype 27-65, EF: M33 2/1 pl. 7, figs. 26, 27, paratype: 27-65,
EF: T 63 2 pl. 7, figs. 28, 29, 30
Type locality: Well 1AS-27-AM
Etymology: After the striae pattern of the grain.
Biochronological range: from UA 4 to UA 7
Description: Monad, radial, isopolar, prolate, triangular-obtuse-convex;
syncolporate, ectocolpi marginate, margo produced by the thinning of the
sexine near to colpi, 2 µm wide, colpi 25 µm long, CPi 0.29, borders straight,
apocolpia field is absent, endopores costate, costae 2 µm wide, 1 µm thick,
pores 4 µm wide, pore 4 µm high, circular; tectate, exine 2.5 µm thick, nexine
1 µm thick, columellae 0.5 µm thick, indistinct, but in plain view is highly
visible, showing a micropitted pattern underneath the tectum, tectum 1 µm
thick, exine decreases towards colpi; sculpture striate, muri 0.5 µm wide, 0.5
µm thick, 0.5 µm apart, striae well developed, striation pattern anastomosing,
longitudinally oriented, parallel to colpi. Dimensions: polar diameter 41 µm,
equatorial diameter 22 µm, polar/equatorial 1.9, n=1; equatorial length 31
(37.3) 44 µm, SD 6.5, equatorial width 29 (35) 44 µm, SD 7.9, equatorial
diameter length/width 1.1, n=3.
Comparisons: Striatricolporites digitatus JARAMILLO&DILCHER, 2001 has
“finger print” striae distribution. Striatricolporites archangelskyi HERNGREEN,
1975 has pores wider (7-10µm). Striatricolporites tenuissimus DUEÑAS, 1980
is semitectate. Striasyncolpites zwaardi (Germeraad et al., 1968) has pores
highly protruding.
Genus Striatricolporites Van der Hammen, 1956 ex
Leidelmeyer, 1966
Striatricolporites poloreticulatus n. sp.
Plate 7, Figs. 35, 36, 37, 38, 39, 40
Diagnosis: Tricolporate, prolate, mid-sized (23-28µm), striate-reticulate, striae
very tenuous, semitectate, heterobrochate.
Specimens: Holotype 27-65, EF: S 28 3 pl. 7, Figs. 35, 36, 37, paratype: 27-
68, EF: J54 2 pl. 7, Figs. 38, 39, 40
Type locality: Well 1AS-27-AM
Biochronological range: from UA 1 to UA 5
Etymology: After the reticulate pattern between striae.
Description: Monad, radial, prolate; tricolporate, colpi costate, costae 1 µm
wide, 1 µm thick at the equator, decreasing to 0.5 µm thick from mesocolpia
to apocolpia, colpi 18 µm long, CPi 0.78, borders straight, ends pointed, pores
simple, pores 4 µm wide, pores 2 µm high, lalongate; semitectate, exine 1 µm
thick, nexine 0.2 µm thick, columellae 0.6 µm thick, distinct, 0.5 µm wide, 1
µm apart, tectum 0.2 µm thick; sculpture striate-reticulate, striae is long,
parallels to the colpi, very thin, 0.5 µm wide, muri 0.5 µm wide, very tenuous,
also reticulate, heterobrochate, lumina decreasing from apocolpia to
mesocolpia where becomes micropitted, in apocolpia area lumina 0.5 µm
wide, polygonal. Dimensions: polar diameter 23 (26) 28 µm, SD 2.2,
equatorial diameter 16 (18.9) 21 µm, SD 2.2, polar/equatorial 1.4, n=4;
Equatorial length 22 µm, equatorial width 21µm, equatorial diameter
length/width 1, n=1.
Comparisons: Striacolporites Sah&Kar, 1970 accommodates tricolporate,
striate-reticulate grains that have lolongate pores. Striatricolporites Van der
Hammen, 1956 ex Leidelmeyer, 1966 although it was doubtfully validate
Jansonius&Hills, 1976 card 2726 is herein accepted. Striatricolporites
Leidelmeyer, 1966 accommodates tricolporate and striate grains.
Striatricolporites digitatus JARAMILLO&DILCHER, 2001 is coarsely striate
and tectate. Striatricolporites tenuissimus Dueñas, 1980 is not reticulate.
Genus Syncolporites Van der Hammen, 1954
Syncolporites sp. 1
Plate 7, Figs. 33, 34
Diagnosis: Syncolporate, triangular-acute-slightly convex, mid-sized (23-24
µm), psilate, tectate.
Specimens: 27-58, EF: K40 4 pl. 7, figs. 33, 34
Description: Monad, radial, isopolar, triangular-acute-slightly convex;
syncolporate, syncolpi simple, borders straight, apocolpia field is present, 4
µm wide, pores vestibulate, costate, costae 1.5 µm wide, 1 µm thick, pores 1
µm wide, 1 µm high, circular; tectate, exine 1 µm thick, nexine 0.2 µm thick,
columellae 0.6 µm high, tectum 0.2 µm thick; sculpture psilate. Dimensions:
equatorial length 23 (23.7) 24 µm, SD 0.6, equatorial width 22 (24) 25 µm, SD
1.7, polar/equatorial 1, n=3.
Comparisons: Syncolporites anibalii Hoorn, 1994 apparently is
heterobrochate. Psilasyncolporites sp. 2 (Jaramillo & Dilcher, 2001) has
apocolpia field is absent.
Genus Tetracolporopollenites Pflug&Thomson, 1953 in
Thomson&Pflug, 1953
Tetracolporopollenites sp. 1
Plate 7, Figs. 41, 42
Diagnosis: Tricolporate, mid-sized (20 µm), psilate, atectate.
Specimens: 27-68, EF: U48 ¾ pl. 7, figs. 41, 42
Biochronological range: from UA 1 to UA 7.
Description: Monad, radial, prolate; tricolporate, colpi 8 µm long, CEi 0.4,
simple, indistinct, borders straight, ends pointed, pores costate, costae 3 µm
wide, 2 µm thick, costae gradually decreasing from mesocolpia to apocolpia,
pores fused together showing a sulcus, lalongate, 8 µm wide, 2 µm high;
atectate, exine 1 µm thick in the polar area, 2 µm thick in the apocolpia;
sculpture psilate. Dimensions: polar diameter 20 (21.5) 23 µm, SD 2.1,
equatorial diameter 14 (15.5) 17 µm, equatorial diameter length/width 1.4,
n=2.
Comparisons: Tetracolporopollenites maculosus (Regali et al., 1974)
Jaramillo & Dilcher, 2001 is larger (24-36 µm) and pores are less lalongate.
Genus Tricolpites Cookson ex Couper, 1953
Tricolpites? pseudoclarensis n. sp.
Plate 7, Figs. 48, 49
Diagnosis: Tricolpate, circular, mid-sized (40 µm), semitectate, reticulate,
colpi slightly marginate, heterobrochate.
Specimens: Holotype 27-68, EF: U47 3/4 pl. 7, Figs. 48, 49, paratype 27-51,
EF: H44 1/3
Type locality: Well 1AS-27-AM
Etymology: After the similarity of T. clarensis
Description: Monad, radial, circular; tricolpate, colpi long, slightly marginate, 2
µm wide, produced by decreasing of the lumina, colpi 30 µm long, CEi 0.8,
polar area 8 µm wide, borders straight, ends pointed; semitectate, exine 1.5
µm thick, nexine 0.8 µm thick, columellae 0.8 µm high, distinct, 0.5 µm wide,
0.5 µm apart, tectum 0.3 µ m thick; sculpture reticulate, lumina 1-2 µm wide,
heterobrochate, decreasing towards both colpi and apocolpia, polygonal, muri
0.5 µm wide, curvimurate, simplicolumellate. Dimensions: equatorial length 32
(36) 40 µm, SD 5.7, equatorial width 30 (33.5) 37 µm, SD 4.9, equatorial
diameter length/width 1.1, n=2.
Comparisons: Tricolpites Cookson ex Couper, 1953 accommodates tricolpate
grains, with reticulum regular over grain. Tricolpites clarensis Gonzalez, 1967
Jaramillo&Dilcher, 2001 has lumina smaller (0.7-1 µ m) and is tectate.
Tricolpites antonii Gonzalez, 1967 Jaramillo and Dilcher, 2001 is smaller (26
µm).
Genus Zonocostites Germeraad, et al., 1968
Zonocostites equatorialis n. sp.
Plate 7, Figs. 43, 44, 45
Diagnosis: Tricolporate, prolate, mid-sized (23-28 µm), micropitted at the
apocolpia, psilate at the mesocolpia, intectate, zonosulculate.
Specimens: Holotype 27-60, EF: S35 2/4 pl. 7, Figs. 43, 44, 45.
Type locality: Well 1AS-27-AM
Etymology: After the presence of zonosulculus
Description: Monad, radial, isopolar, prolate; tricolporate, colpi long, simple,
intruding, borders straight, ends pointed reaching polar area, colpi 15 µm
long, CPi 0.6, the pores are fused together forming a zonasulculus, borders
simple, pores 4 µm high; intectate, exine 1 µm thick, exine thicker in polar
area; sculpture micropitted at the apocolpia, lumina <0.5 µm, circular, densely
distributed, psilate at the mesocolpia. Dimensions: Polar diameter 23 (25.5)
28 µm, SD 3.5; Equatorial diameter 18 (19.5) 21 µm, SD 2.1; polar/equatorial
1.3, n=2.
Comparisons: Zonocostites minor (Jaramillo and Dilcher, 2001) is smaller (16
µm).
5. Acknowledgements
We thank to the Smithsonian Tropical Research Institute and INPA where this
research was carried out. We also thank DNPM, especially Dr. Fernando
Burgos and Gert Woeltje for the sampling permits of the Amazon cores. We
thank to ICP-Instituto Colombiano de Petroleo to samples procedure. Thanks
to Dr. Jackson Paz, MsC. Carlos Arias, Dr. Fatima Leite, Dr. Edgardo
Latrubesse for the cooperation in some graphs herein used and comments.
This study was supported by CAPES and CNPq. To Carmen Schloeder by the
abstract translation.
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7.0 explanations of plates
Plate 1
1,2,3
Cingulatisporites peruanus (Hoorn, 1994a) n. comb.
4,5,6
Cingulatisporites rugulatus n. sp.
7
Crassoretitriletes vanraadshoovenii Germeraad et al. 1968.
8,9
Cyathidites sp. 1
10
Deltoidospora adriennis (Potonié & Gelletich, 1933) Frederiksen, 1983
11,12,13,14
Distaverrusporites margaritatus (Muller, 1968)
15,16
Echinatisporis circularis n. sp.
17,18
Foveotriletes ornatus (Regali et al., 1974)
19,20
Kuylisporites waterbolkii Potoníe, 1956
21
Echinatisporis muelleri Regali et al. 1974 n. comb.
22
Magnastriatites grandiosus (Kedves & De Porta, 1963) (Dueñas, 1980b)
23,24
Hydrosporis minor n. sp.
25,26
Polypodiaceiosporites? laevigatus n. sp.
27,28
Microfoveolatisporis sp. 1
29,30
Matonisporites muelleri Playford 1982
Plate 2
1,2,3
Polypodiaceiosporites pseudopsilatus Lorente 1986
4,5
Polypodiisporites pseudoreticulatum n. sp.
6,7
Polypodiisporites aff. specious Sah, 1967
8,9
Polypodiisporites usmensis (Van der Hammen, 1956b) (Germeraad et al., 1968) Khan & Martin, 1972
10,11
Polypodiisporites? planus n .sp.
12,13
Psilatriletes lobatus (Hoorn, 1994a)
14,15
Psilatriletes sp.1
16,17,18
Pteridaceoisporis gemmatus n. sp.
19,20
Tuberositriletes? crassitudatis n. sp.
21,22
Rugulatisporites sp. 1
23,24
Verrucatotriletes bullatus (Van Hoeken-Klinkenberg, 1964)
25,26
Retitriletes murielevatus n. sp.
Plate 3
1,2
Arecipites perfectus n. sp.
3,4
Arecipites? polaris n. sp.
5,6
Bombacacidites araracuarensis (Hoorn, 1994b)
7,8,9
Bombacacidites simpliciriloensis n. sp.
10,11,12
Bombacacidites sp.1
13
Bombacacidites zuatensis Lorente, 1986
14,15,16
Bombacacidites fossulatus n. sp.
17,18
Bombacacidites nacimientoensis Anderson, 1960 Elsik, 1968
19,20
Cistacearumpollenites poruscircularis n. sp.
21,22
Byttneripollis ruedae n. sp.
23,24
Corsinipollenites oculusnoctis Thiergart, 1940 Nakoman, 1965
25
Corsinipollenites oculusnoctis Thiergart, 1940 Nakoman, 1965 (Tetrads)
26,27,28
Cichoreacidites longispinosus Lorente, 1986 n. comb.
29
Clavainaperturites microclavatus (Hoorn, 1994a)
30,31
Corsinipollenites scabratus n. sp.
32,33
Corsinipollenites collaris n. sp.
Plate 4
1,2
Cricotriporites sp.1
3,4
Crotonoidaepollenites reticulatus n. sp.
5,6,7
Crototricolpites finitus (Equatorial view) n. sp.
8,9
Crototricolpites finitus (Polar view) n. sp.
10,11,12
Ctenolophonidites suigeneris n. sp.
13,14
Dicolpopollenites obtusipolus (Paratype) n. sp.
15,16
Dicolpopollenites obtusipolus (Holotype) n. sp.
17,18,19
Echiperiporites estelae Germeraad et al. 1968
20,21
Echiperiporites jutaiensis n. sp.
22,23
Echiperiporites lophatus n. sp.
24,25
Gomphrenipollis minima n. sp.
26,27
Echiperiporites intectatus n. sp.
28,29,30
Heterocolpites brevicolpatus n. sp.
31
Foveotricolporites pseudodubiosus n. sp.
32,33,34
Glencopollis curvimuratus n. sp.
35,36
Heterocolpites rotundus Hoorn, 1993
37,38
Heterocolpites verrucosus Hoorn, 1993
39,40
Foveotricolporites lenticuloides (Holotype) n. sp.
41,42
Foveotricolporites lenticuloides (Paratype) n. sp.
43,44
Horniella caribbiensis (Muller et al., 1987) n. comb.
Plate 5
1,2
Horniella morenoi n. sp.
3,4
Ladakhipollenites floratus n. sp.
5,6
Inaperturopollenites sp.1
7,8
Ladakhipollenites rectangularis (Holotype) n. sp.
9,10
Ladakhipollenites rectangularis (Paratype) n. sp.
11,12
Horniella? megaporatus n. sp.
13,14,15
Ilexpollenites tropicalis n. sp.
16,17
Loranthacites psilatus n. sp.
18,19
Loranthacidites sp. 1
20,21
Lakiapollis costatus n. sp.
22,23,24
Malvacipolloides sp.1
25,26
Malvacipolloides maristellae (Muller et al., 1987) n. comb.
27,28
Malvacipolloides sp. 2
29,30
Meliapollis? sp. 1
31,32
Margocolporites muellerae n. sp.
33,34
Margocolporites fastigiatus (Holotype) n. sp.
35,36
Margocolporites fastigiatus (Paratype) n. sp.
37,38
Monocolpopollenites sp 1
39,40
Margocolporites pseudodemicolpatus n. sp.
41,42
Margotricolporites sp.1
43,44
Malvacipolloides? sp. 3
Plate 6
1,2
Multiporopollenites crassinexinatus n. sp.
3,4
Paleosantalaceapidites sp. 1
5,6
Parsonisidites? brenacii n. sp.
7,8,9,10
Psilabrevitricolporites devriesi Lorente 1986 n. comb.
11,12,13
Psilabrevicolpites flexibilis van Hoeken-Klinkenberg, 1966
14,15
Psilabrevitricolporites sp. 1
16
Proxapertites tertiaria Van der Hammen & Garcia 1966
17,18
Psilastephanoporites herngreenii Hoorn 1993
19,20
Retibrevitricolpites sp. 1
21,22,23
Retistephanocolporites sp.1
24,25
Psilaperiporites sp. 1
26,27,28
Psilastephanoporites sp. 1
29,30
Retitrescolpites sp. 2
31,32,33
Retistephanocolpites circularis n. sp.
34,35,36,37
Retibrevitricolporites yavarensis Hoorn 1993 n. comb.
38,39
Retitrescolpites? sp. 1
40,41
Retitrescolpites? costelas (Paratype) n. sp.
42,43,44
Retitrescolpites? costelas (Holotype) n. sp.
45,46
Retitriporites rotundus (Paratype) n. sp.
47,48
Retitriporites rotundus (Holotype) n. sp.
Plate 7
1,2
Retitriporites sp. 1
3,4
Rhoipites gigantiporus n. sp.
5,6
Rhoipites gigantiporus n. sp.
7
Siltaria amygdalas n. sp.
8,9,10
Siltaria hammeni n. sp.
11,12
Siltaria hammeni n. sp.
13,14,15,16,17
Siltaria mariposa Leidelmeyer, 1966 Jaramillo and Dilcher, 2001
18,19
Siltaria pseudosyncolpata n. sp.
20,21,22
Siltaria santaisabelensis (Hoorn, 1994b) n. comb.
23,24,25
Siltaria sp.1
26,27
Striasyncolporites anastomosatus (Holotype) n. sp.
28,29,30
Striasyncolporites anastomosatus (Paratype) n. sp.
31,32
Siltaria tectata n. sp.
33,34
Syncolporites sp. 1
35,36,37
Striatricolporites poloreticulatus (Holotype) n. sp.
38,39,40
Striatricolporites poloreticulatus (Paratype) n. sp.
41,42
Tetracolporopollenites sp. 1
43,44,45
Zonocostites equatorialis n. sp.
46,47
Scabratricolpites elongatus n. sp.
48,49
Tricolpites? pseudoclarensis n. sp.
1
2
3
4
5
6
7
8
9
10
11 12
13
14
15
16
17
18
19
20
21
22
23 24
25
26
27
28
29
30
1
23
4
5
67
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
1
2
4
3
5
6
7
89
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
28
27
29
30
31
32
33
1
23
4
5
6
7
8
9
10
11 12
18
13
14
15
16
17
24
19
20 21
22
23
25
26 27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
1
2
3
4
5
6
7
89
10
11 12
18
13
14
15
16
17
24
19
20
21
22
23
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19 20
21
22
23
24
25
26
27
28
29
30
31
32 33
34
35
36 37
38
39
40
41
42
43
44
45
46
47
48
1
2
3
4
8
9
10
11 12
13
14
15
7
16
17
19
18
21
20
22
23
24
25
26
27
28
29
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31 32
33
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48
ANEXO II: PAPER PUBLICADO DISCUTINDO OS PROBLEMAS
BIOESTRATIGRÁFICOS DO MIOCENO DA AMAZÔNIA
Late Miocene continental sedimentation in southwestern Amazonia
and its regional significance: Biotic and geological evidence
Edgardo M. Latrubesse
a,
*
, Silane A.F. da Silva
b
, Mario Cozzuol
c
, Maria Lu
´
cia Absy
b
a
Universidad Nacional de La Plata, FCNyM, Instituto de Geomorfologia y Suelos-IGS, Calle 3 N 584, (1900), La Plata, Argentina
b
Instituto Nacional de Pesquisas da Amazo
ˆ
nia, INPA-National Institute of Amazon Research, Laborato
´
rio de Palinologia,
Avenida Andre
´
Arau
´
jo, No. 2936, Aleixo 69011-970, Manaus, Amazonas, Brazil
c
Laboratorio de Paleontologia Museu de Cie
ˆ
ncias e Tecnologia, PUC-RS, Avda. Ipiranga 6681, Porto Alegre, RS, Brazil
Received 1 July 2004; accepted 1 June 2006
Abstract
Fossil content (vertebrate paleofauna and palynology) indicates that the sediments of the Solimo
˜
es Formation in Acre (SW Brazilian
Amazonia) are continental, having been deposited by avulsive fluvial belts in a floodbasin–floodplain environment. The main source area
was the Andes chain. Widespread lacustrine swampy deposits, stacked channel deposits, and paleosoils are typical elements that characterize
the Solimo
˜
es Formation sediments that outcrop in southwestern Brazilian Amazonia. New data on fossil vertebrate assemblages and pal-
ynology corroborate the Late Miocene age suggested previously and assign the fossils to the Huayquerian mammalian biozone, spanning 9–
6.5 Ma. These geological and paleontological data show that the existence of an intracontinental seaway through SW Amazonia during the
Late Miocene (11–10 Ma), connecting the Caribbean Sea with the Parana Basin as previously proposed is unsustainable, because the sed-
iments used by previous authors to propose the seaway were deposited in a continental environment and are younger than 11–10 Ma.
Ó 2006 Elsevier Ltd. All rights reserved.
Keywords: Solimo
˜
es formation; Amazon; Paleogeography; Paleoecology; Late Miocene
1. Introduction
The Amazon, the world’s largest fluvial system, is of
fundamental importance for understanding Late Cenozoic
environmental change. However, much of Ama zonia is
inaccessible and has not been studied in detail, and the lim-
ited investigations to date have resulted in many controver-
sies. Brazilian researchers (including the authors) have been
working since the 1990s on the Neogene record of south-
western Brazilian Amazonia. Part of Amazonia, consisting
of the Brazilian state of Acre and neighboring parts of
Amazonas and Rondonia, were visited by an IGCP 449
field excursion organized by E.M. Latrubesse and J.C.
Stevaux in 2003 (e.g., Westaway, 2006), when some of these
controversies were discussed at length and the results
obtained wer e discussed with specialists from several coun-
tries. This article presents new evidence and synthesizes our
results in relation to these issues.
During recent decades, preliminary data sets pertaining
to the Cenozoic sediments of SW Amazo
ˆ
nia have been gen-
erated (Radambrasil, 1976, 1978; Latrubesse, 1992; Latru-
besse et al., 1997). One of the best known publications, by
Ra
¨
sa
¨
nen et al. (1995), proposed the existence of an intra-
continental seaway through western Amazonia, linking
the western Caribbean with the Rio de la Plata estuary
via western Amazonia and the modern Parana drainage
basin (Fig. 1).
This proposal been received favorably by some research-
ers, mainly paleontologists and biogeographers who regard
it as a new paleogeographic alternative to understanding
biogeographic patterns in South America (Webb, 1996;
Lovejoy et al., 1998, 2006; Albert et al., 2006). However,
this seaway model has received some criticism (Hoorn,
1996; Marshall and Lundberg, 1996; Praxton et al.,
0895-9811/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jsames.2006.09.021
*
Corresponding author.
E-mail address: [email protected] (E.M. Latrubesse).
www.elsevier.com/locate/jsames
Journal of South American Earth Sciences 23 (2007) 61–80
1996), but only circumstantial evidence against it was pre-
sented. For this reason, geologists working in the Parana–
Chaco Basin were tempted to correlate data from the Cha-
co Basin with sediments outcropping in Acre, speculating
on marine connections and ingressions from both basins
in the Bolivian Chaco during the Late Miocene (Hernandez
et al., 2005; Hulka et al., 2006 ). A new publication by
Rebata et al. (2006) on the Pastaza–Maran
˜
on Basin contin-
ues to postulate marine incurs ions in southwestern Amazo-
nia during the Late Miocene. We show that the existence of
such an intracontinental seaway is unsustainable in the
middle–later part of the Late Miocene, in light of the geo-
logical and paleontological evidence presently available in
SW Brazilian Amazonia (the same source area of Ra
¨
sa
¨
nen
et al., 1995). We also suggest that the proposal derived
from misunderstandings by Ra
¨
sa
¨
nen et al. (1995) of the
stratigraphy and fossil fauna, which led those authors
incorrectly to correlate sediments of the Amazon and Par-
ana basins.
2. Geological interpretation
Ra
¨
sa
¨
nen et al. (1995) describe outcrops on the Purus
and Acre rivers, as well as along BR-364 road from Rio
Branco to Sena Madureira city, in SW Amazonia, inter-
preting them as deposit ed within tidal flats and estuarine
environments. We are familiar with these and many other
outcrops but interpret the same deposits differently. Late
Cenozoic sedim ents, mainly sandstones, siltstones, and
claystones, cover most of western Amazonia and have been
interpreted independently as deposited in a continental
fluvial/lacustrine environment (Radambrasil, 1976, 1978;
Latrubesse, 1992). These sediments were included in a sin-
gle lithostratigraphic unit named the Solim oes Formation
(Caputo et al., 1971), which reaches thicknesses of up to
1800 m (borehole I Nst-1-AM; Radambrasil, 1978); in Acre
state, these Cenozoic sediments are up to 800 m thick
(Fig. 2). Westaway (2006) has suggested that in view of
its vast extent and considerable thickness, this sedimentary
unit could deserve at least the stratigraphic status of a
group, not a formation.
Acre state is characterized by a dissected fluvial land-
scape caused by incision into the uppermost part of the Sol-
imoes Formation deposits (Fig. 3). The outcrops analyzed
by Ra
¨
sa
¨
nen et al. (1995), and investigated by us, are along
river banks and roads. The relief in this region, between the
highest parts of the landscape and valley floor levels, is
nowhere more than approximately 80 m. Therefore, we
Fig. 1. (A) Inset showing the seaway inferred to have existed during the Late Miocene by Ra
¨
sa
¨
nen et al. (1995), connecting the Caribbean Sea with the
south Atlantic through the Venezuelan/Colombian Llanos Basin, western Amazonia, the Beni-Chaco plain, and the Parana Basin in Argentina. (B) Late
Miocene model proposed herein. The position of the flat slab of the central Andes at 2–15°S is indicated. The Late Miocene deposits of the Mesopotamian
(lowermost levels of the Ituzaingo Formation) and the Kiyu
´
Formation in the La Plata Basin, the Urumaco Formation in Venezuela, and the continental
sedimentation of the Solimo
˜
es Formation is recorded. The occurrence of Late Miocene discordance in the coastal Barreiras Formation (BFD) sediments
and the intra-Chaco discordance in Bolivia (ICHD) is indicated. In the sub-Andean Chaco area of south central Bolivia, the Tariquia Formation should be
recorded at this time. Hoorn (1994a) did not record Late Miocene sediments in the northernmost outcrops of the lowlands of southeastern Colombia but
in the Paleozoic rocks of the Araraquara Formation and the outcrops of the lower–middle Miocene sediments Marin
˜
ame unit (L/MM?), which should be
an obstacle for marine ingressions in the early Late Miocene coming from the Caribbean Sea (Hoorn, 1993).
62 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
can discuss, at most, the uppermost 80 m of a deposit that
reaches 800 m thick. Our surveys along the banks of the
Acre, Iaco, Purus, Jurua, and Moa rivers and in road cuts
lead us to identify two main facies assemblages: a channel-
dominated assemblage and a floodplain–lacustrine low-
energy assemblage.
The channel assemblage is typically composed of red–
brown to brown sand, silty and clayey sand, and intrafor-
mational mud ball beds. It is dominated by lateral accre-
tion structures and abandoned chan nels and shows
characteristic major trough cross-bedding structures and
ripples (Figs. 4 and 5). The predominant low-energy assem-
blage is composed mainly of green to grey–green clay and
silty clay and interpreted as deposited in a floodplain/
lacustrine/paludal environment (Fig. 6). These sediments
show mainly massive structure and lamination in some
cases. Paleosols are marked by the presence of nodular
horizons, rhizolits, root casts, mudcracks, and mottled
Fig. 2. Isopach map of the Solimo
˜
es Formation (from Maia et al., 1977). Numbered circular areas indicate main areas with Late Miocene fossiliferous,
palynological, and/or geological data. 1, Upper Acre River; 2, Acre River upstream of Rio Branco (also studied by Ra
¨
sa
¨
nen et al., 1995); 3, BR 364 from
Rio Branco to Sena Madureira; 4, BR 364 from Sena Madureira to Manuel Urbano and outcrops along the Iaco and Purus rivers; 5, Upper Jurua. Square
in the northwestern corner indicates the area studied by Hoorn (1993, 1994a,b).
Fig. 3. Schematic section showing the main elements of the landscape in SW Brazilian Amazonia (lowlands). Tertiary sediments of the Solimo
˜
es
Formation outcrop along the banks of main rivers and along the watershed areas, mainly exposed on road cuts.
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 63
structures (Fig. 6). In some more lacust rine sediments, con-
volute structures are also found. Differences in color, vary-
ing from green or grey–green to pale red, can be attributed
to differences in water depth and oxygenation. Lignite beds
are scarce in the swampy lacustrine sediments that crop out
in Acre. However, in some localities, such as the upper
Acre River, it is possible to find fossilized wood and other
organic matter or pyrite associated with woody fragments
or organic beds.
In both facies assemblages, fossil bones, gypsum
veins, and calcareous concretions occur. The sediments
are rich in the bones of autochthonous and para-
utochthonous vertebrates and bones and shells of inver-
tebrates such as bivalves and gastropods. Abundant
crocodilian coprolites have also been recorded in some
outcrops.
The channel assemblage can be interpreted in terms of
active and unstable channels with sequences of fining-
upward sediments and cycles of cut and fill. Point-bar
accretion surfaces are formed by fine-grained sediment
(fine sand, silt, mud), with ripple structures predominant
in the bedsets of these lateral accretion deposits. A good
example of fine, dominated point bar deposits are those
described by Ra
¨
sa
¨
nen et al. (1995) at Seringal Amapa, in
the Acre River, as a point bar that formed under the influ-
ence of tidal conditions. We posit that the outcrop repre-
Fig. 4. Amapa outcrops in the Acre River, upstream of Rio Branco, described by Ra
¨
sa
¨
nen et al. (1995) as a point bar generated below tidal influence
generated by the seaway (location, area 2 of Fig. 2). We interpret the deposits as formed by lateral accretion structures. Note the decrease in bed thickness
from 1 to 2 and floodplain-dominating deposits in the uppermost part of the profile (3) indicated in (B). The channel macroform is mainly formed by large,
20–80 cm thick sets of inclined fine-sand point bar ripple drift lamination, predominantly B type with top sets (A) and between thin beds of fine sediments
(B). (C) Details of ripple drift lamination.
64 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
sents a fluvial point-bar depo sit with rapid fine sedimenta-
tion. This channel macroform is mainly formed by 20–
80 cm thick, inclined, fine-sand point-bar ripple drift lami-
nation, predominantly B type with topsets (Fig. 4A and B).
Bottomsets (total 5 cm thick) indicate high sedimenta-
tion rates. The 10–20 cm thick, intercalated, massive,
muddy beds suggest backwater ponding, as interpreted
by Westaway (2006). Thus, these kinds of deposits indicate
highly seasonal behavior, with peaks of suspended sedi-
ment transport (producing sand laminations) alternating
with rapid falls in water level or slackwater effects (produc-
ing mud laminations). Such deposits are widespread
throughout the Solimo
˜
es Formation.
Other important sedimentological aspects in the chan-
nel assemblages includ e the presence of nonrepetitive
scroll structures and abruptly abandoned channels, typi-
cally without oxbow-lacustrine deposits. Thus, avulsion
was an important mechanism of channel adjustment.
Associated with paleochannel features, abundant finely
laminated to massive fine sediment plugs can be found,
which indicate that channels were filled quickly by fine-
grained sediments. Coarse sediments are represented and
restricted to intraformational mudballs (Fig. 5). Mudballs
are typical channel lithofacies that represent channel reac-
tivation inside an aggradational fluvial system with a ten-
dency toward subsidence, which erode/run on a muddy
river bed cutting floodplain or lake deposits. Mudballs
are eroded and shortly transported by severa l processes,
such as erosion in a muddy bottom channel; the entrance
of a channel in muddy sediments, mainly in a saturated
floodplain/lake; the generation of a new fluvial belt by
avulsion that cut the fine-grained sediments of the flood-
plain again; and mass movements along the banks that
introduced sediments into the channel. All these mecha-
nisms are recorded in the sediments of the Solimo
˜
es
Formation.
Large channel macroforms are clearly associated with
floodplain deposits and lateral and vertical relations
between channel macroforms, and floodplain deposits can
be identified in the field (Fig. 5). These fluvial systems typ-
ically transported fine-grained suspended sediments.
The association of sedimentary environments, such as
widespread shallow lacustrine swampy deposits, paleosols,
and stacked channel deposits, with abundant terrestrial
and aquatic vertebrate remains indicates the existence of
a large floodbasin, exhibiting floodplain surfaces with
Fig. 5. (A) Channel macroform related to crevasse splay or small delta in water-saturated environment, road cut, BR 364 from Rio Branco to Sena
Madureira (9°26
0
58.97 S, 68°23
0
29.97 W, area 3 of Fig. 2). (B) Channel cuts and enters lacustrine/marshy deposits. Road cuts BR 364 from Rio Branco to
Sena Madureira. (B–D) Relate to this kind of deposit in outcrops along the same area. (B) Sandy sets of the channel environment with B-type ripples; (C)
convolute beds in fine lacustrine deposits; (D) intraformational conglomerate indicating flash entrance and/or reactivation of a channel in a splay/delta.
Sediments indicate channel erosion in a depositional plain. Mudballs are the coarser fraction, transported very short distances, by the suspended load
fluvial systems of the Solimo
˜
es Formation.
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 65
paleosols, avulsive channel systems, crevasse splays, and
deltaic environments.
Several other Late Cenozoic sedimentological systems
are closely analogous to the Solimo
˜
es Formation, as dis-
cussed at the field conference Amazon 2003-IGCP 449
(Westaway, 2006). Large depositional megafans are char-
acteristic of tropical systems. In active orogenic belts and
foreland settings, some of the world’s largest megafans,
extending over thousands of square kilometers, have devel-
oped, such as the Kosi and Gandak megafans in the Gan-
getic plains of India and the Parapetı
´
, Pilcomayo, and
Bermejo fans in the Chaco plains of South America (Latru-
besse et al., 2005). It is widely recognized that large sedi-
ment loads, frequent avulsio n, low longitudinal gradients,
and highly variable flow regimes are major factors control-
ling the development of such fans.
An approximately similar modern analogue environ-
ment to the Solimo
˜
es Formation deposits cropping out in
Acre is suggested by the Quaternary Chaco system. With
an area of >800,000 km
2
, the Chaco plain spreads across
Bolivia, Paraguay, and northern Argentina. The climate
is wet/dry tropical, with annual precipitation decreasing
from 1000 to 2500 mm in the sub-Andean zone to
1200 mm in the Oriental Chaco and 400 mm in the Occi-
dental Chaco. Sedimentation in the Chaco consists of large
Quaternary alluvial fans formed by hyperavulsive rivers,
which represent the largest fluvial-like system of coalescing
fans in the world. These fans are formed from north to
south by the Grande, Parapetı
´
, Pı
´
lcomayo, Bermejo, and
Salado rivers (Iriondo, 1993; Wilkinson et al., 2006). In
the Upper Paraguay Basin, a large wetland/floodbasin
area, the Pantanal, formed of extensive megafans (Sa
˜
o
Lourenc¸o, Taquarı
´
, etc.) is fed by the Brazilian highlands
close to the megadepos itional fans system to the east. These
megafans are formed by well-delimited alluvial belts creat-
ed during humid periods and smaller and less stable paleo-
channels active during dry periods as a response to the
climatic changes of the Late Quaternary. Avulsion is the
main mechanism producing abandoned alluvial belts, with
fine sediments predominant in the plains (Assine, 2005).
Fig. 6. (A) Pedogenic features in floodplain deposits (massive silty/clayey sediments) in road outcrops of BR 364, location 9°37
0
17.25 S, 68°14
0
12W, area 3
of Fig. 2. (B) Paleosoils characterized by blocky peds, mottles, root casts, and rhizoliths. Floodplain paleosoils are covered by ‘‘wetter’’ floodplain deposits
with less pronounced pedogenetic features (above arrows). (C) Paleosoil in a Acre River bank outcrop upstream of profile described by Ra
¨
sa
¨
nen et al.
(1995), in Amapa (area 2, Fig. 2). The outcrops extend from 10°02
0
1.74
00
S, 67°52
0
29.09W to some hundreds of meters upstream on the left banks of the
Acre River. The paleosoil is found in a fine sediment-dominated sequence of floodplain deposits. Vertebrates and freshwater bivalves occur in floodplain
deposits, such as Pachydon sp., Castalia sp., Prisodon sp., Diplodon sp., and Mycetopoda sp. (material identified by Marı
´
a Ine
ˆ
s Feijo
´
Ramos, Museu
Paraense Emilio Goeldi, Bele
´
m, Brazil). (D) Floodplain deposits in Preventorio, left bank of the Acre River, Rio Branco urban area. Arrows indicate
vertebrate fossiliferous levels. Remains of Late Miocene vertebrates stored in the Laborato
´
rio of Paleontological Research of the Federal University of
Acre; the most spectacular piece is a jaw of the giant crocodile Purusaurus brassiliensis.
66 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
Swampy areas are widespread, with more than 125,000 km
2
of the Bermejo and Pilcomayo fans flooded (Iriondo,
1993). Parts of the Chaco and Pantanal are hyposaline.
Sediments deposited by hyperavulsive systems in a fore-
land basin are also recorded in some units of the Lower
and Middle Siwalik deposits and their modern analogues
in the Gangetic plain (Jain and Sinha, 2003). These fluvial
sequences are characterized by a predominance of stacked
sandstones and overbank mudstones, paleosols, and abun-
dant fossil content (e.g., Beherensmeyer, 1987; Beherens-
meyer and Tauxe, 1982; Willis and Behrensmeyer, 1994;
Bhatia, 2003; Kumar et al., 2003).
The Chaco, Indogangetic plain, and Solimo
˜
es Forma-
tion deposits indicate broadly similar processes of sedimen-
tation. The most important difference is that deposition
was more distal and conditions were wetter in the Amazon
during the Upper Miocene than in the Quaternary of the
Chaco and the Late Miocene Siwaliks, as indicated by
the tropical fauna and vegetation recorded in the Solimo
˜
es
Formation. Aeolian deposits, common in Chaco, and thick
calcrete paleosoils, found in the Indogangetic plain, have
not been recorded in the Solimo
˜
es Formation. Conversely,
permanent water bodies (swamps, shallow lakes) were
widespread during deposition of the Solim oes Formation,
indicating that southwestern Amazonia acted as a floodba-
sin similar to the present-day Pantanal system but fed from
the Andes.
3. Fossil vertebrates and their interpretation
Land mammal assemblages are the most used biostrati -
graphic evidence to correlate Tertiary continental deposits
in South America (Flynn and Swisher, 1995). As a conse-
quence of isolation during most of the Cenozoic, because
of the absence of a land bridge linking South and North
America, South America has a distinct Cenozoic fauna.
This uniq ueness has long been recognized, notably as a
result of work on mammalian biostratigrap hy by the
Argentinean paleontologist Florentino Ameghino in the
late nineteenth and early twentieth centuries.
Originally, Latrubesse (1992) and Latrubesse et al.
(1997) proposed that the fossil fauna of Acre state belongs
to the Huayquerian mammal age, possibly extending to the
Montehermosan age. They also proposed a correlation of
the Solimo
˜
es Formation fossil assemblage with the Meso-
potamiense from Argentina and the Urumaco in Venezue-
la. Given the current evidence and the stratigraphic
advances reached in Argentina and Venezuela, the fossil
vertebrates of Acre are now attributable to the Huay-
querian–Mesopotamian South America Land Mammal
Age (SALMA) (9–6.5 Ma), defined mainly for Mesopota-
mian fauna (Cione et al., 2001).
Fossils were first recorded in Acre by the Chandless
expedition in 1866. Fundamental reviews of these verte-
brates have been writt en by Rancy (1985, 1991) and Webb
and Rancy (1996). The vertebrate fauna of Acre is one of
the most complete and complex in the Late Miocene of
South America, comprising 51 genera. The fossils were col-
lected along river banks and from the uppermost levels
cropping out on the hills of the lowland dissected plain
(Fig. 3). M ost species can be found in the Laboratorio de
Pesquisas Paleontolo
´
gicas of the Federal University of
Acre in Rio Branco. Fossils have been mainly found
in situ in both facies assemblages, but the floodplain/lacus-
trine/paludal assemblage has yielded more complete assem-
blages wi th better preservation because of the low-energy
depositional environment (Fig. 7).
We reviewed the fossil record of vertebrates from the
Solimo
˜
es Formation in SW Brazilian Amazonia, the Uru-
maco Formation in Venezuela, and the Mesopotamian of
Argentina (Table 1). The data from Acre were taken from
previous publications, mainly Campbell et al. (2000),
Latrubesse et al. (1997), and from the collections of the
Laborato
´
rio de Pesquisas Paleontolo
´
gicas and our own
data. Faunal data for the Mesopotamian are from Cione
et al. (2001), the collections of La Plata Museum of Natu-
ral Sciences (La Plata city), and the Argentinean Museum
of Natural Sciences ‘‘Bernardino Rivadavia’’ (Buenos
Aires) in Argentina, as well as our own data. Data from
the Venezuelan localities are from Marshall et al. (1993),
Sa
´
nchez-Villagra et al. (2003), and Linares (2004).
Twenty genera found in Acre are also present in the
Mesopotamian fauna of Argentina, with 11 species in com-
mon between both assemblages, including the rodents Pot-
amarchus murinus, Neoepiblema horridula, Phoberomys
burmeisteri, and Kiyutherium orientalis
, as well as other
amniote groups. A list of the fossil amniotes from the Mes-
opotamia (Argentina), Sol imo
˜
es For mation (Brazil), and
Urumaco (Venezuela) appears in Table 1. Se veral taxa
shared with the Mesopotamian fauna are also found in
Urumaco fauna from northern Venezuela, such as the tox-
odontid Grynodon and the roden ts Kiyutherium and Phob-
eromys. The Acre faunal assemblage preceded the Great
American Biotic Interchange (GABI), as indicated by the
Fig. 7. Fossiliferous outcrop of the Solimo
˜
es Formation in the Acre River
upstream of Brasileia, Calvalcante locality (10°55
0
42
00
S, 69°49
0
53
00
W, area
1 of Fig. 2). The remains belong to a Late Miocene Toxodontidae found in
the low-energy facies assemblage.
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 67
Table 1
List of the Late Miocene (Huayquerian–Mesopotamian SALMA) amniotes (mammals, reptiles,
and birds) from the Solimo
˜
es Formation in SW Brazilian Amazonia, Urumaco Formation in
Venezuela, and the Mesopotamian (lowermost levels of Ituzaingo
´
Formation) in Argentina
‘‘Mesopotamian’’ Acre Urumaco
Rodentia
Brianomys X
Carlesia X
Diaphoromys X
Doellomys X
Eumegamysops X
Isostylomys X
Paranamys X
Pentastylodon X
Pentastylomys X
Pseusygmodus X
Tetrastylomys X
Protomegamys X
Neoepiblema X X X
Phoberomys X X X
Kiyutherium X X X
Cardiatherium X X
Potamarchus X X X
Tetrastylus X X X
Gyriabrus X X
Eumegamys X X X
Telicomys X X
Simplimus X
‘‘Scleromys’’ X
Lagostomopsys X
Perimys X
Protabrocoma X
Eumysops X
Haplostropha X
Paradoxomys X
Steiromys X
Microsteiromys X
Cardiomys X
Caviodon X
Paleocavia X
Paradimys X
Pliodolichotis X
Anastochoerus X
Anchimys X
Anchimisops X
Contracavia X
Plexochoerus X
Procardiatherium X
Protohydrochoerus X
Colpostemus X
Myocastor X
Xenarthra
Pliomegatherium X
Promegatherium X
Pyramiodontotherium X
Pronothrotherium X X
Neohapalops X
Pliomophus X
Menilau? X
Torrellia X
Paranabradys X
Orthotherium X
Amphiocnus X
Promegalonyx X
Megalonychops X
Promylodon X
Prolestodon X
Megabradys X
Strabassodon X
Sphenotherium X
Octomylodon X
Diedomus X
Octodontobradys X
Urumacotherium X X
Acretherium X
Pseudoprepotherium X
Prepotherium X
Ranculus X X
Plohophorus X X
Paraglyptodon X X
Berthawyleria X
Hoplophorus X
Trachycalyptus X
Line missing
Paleohoplophorus X
Table 1 (continued)
‘‘Mesopotamian’’ Acre Urumaco
Protoglyptodon X
Parahoplophorus X
Uratherium X
Pseudoeuryurus X
Comaphorus X
Eleuterocercus X
Chlamyphractus X
Dasypus X
Chasicotatus X
Macroeuphractus X
Proeuphractus X
Zaedius(?) X
Kraglievichia X X
Scirrotherium X
Asterotemma X
Neoglyptatelus X X
Notoungulata
Adinotherium X
Bernia X
Xotodon X
Eutomodus X
Stenotephanus X
Haplodontotherium X
Pachynodon X
Dilobodon X
Dinotoxodon X
Eutypotherium X
Munizia X
Protypotherium X X
Abrothrodon X
Gyrinodon X X
Trigonodops X
Trigodon X
Plesiotoxodon X
Toxodontherium X X
Neotrigodon X
Neotoxodon X
Mesenodon X
Mesotoxodon X
Minitixodon X
Paleotoxodon X X
Oneotherium X
Litopterna
Protherotherium X X
Epitherium X
Brachytherium X
Licaphrium X X
Thoatherium X
Carlosoma(name?)
X
Scalabrinitherium X
Oxyodontotherium X
Mesorhinus X
Paranauchenia X
Promacrauchenia X
Culinia X
Sirenia
Ribodon X X X
Cetacea
Ischyrorhynchus X X X
Saurocetes X X X
Chiroptera
Noctilio X
Proboscidea
Amahuacatherium X
Primates
Acrecebus X
Stirtonia X
Solimoea X
Carnivora
Cyonasua X
Marsupialia
Didelphis X
Zygolestes X
Notictis X
Line missing
68 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
absence of immigrant mammals like Sigmodontine rodents.
Nevertheless, some elements suggest that a low rate
exchange already had been initiated at the time of connec-
tion between the Americas (Campbell et al., 2000, 2001;
Cione et al., 2001).
The fossil vertebrates do not support the hypothesis of a
marine environment, even though the richest faunal groups
are aquatic: crocodilians, turtles, a nd fish. Giant alligator-
ids such as Purussaurus (largest Cenozoic terrestrial pred a-
tor, 15 m long) (Fi g. 8) and other alligatorids, gavials,
crocodilids, and the extinct endemic family Netosuchidae
indicate a greater diversity of crocodilians in this region
than any other region, past or present. The river turtle fam-
ily Pelomedusidae, endemic to South America, is a good
indicator of stable water bodies with abundant vegetation
and a tropical to subtropical climate. Bony and cartilagi-
nous fish, reptiles, cetaceans, and sirenians (manatees) indi-
cate a large flooded basin with shallow lakes and swamps,
crossed by fluvial belts. Some fishes such as Arapaima,
Hoplias, Colosoma, and other genera continue to be found
today in the fluvial systems of Amazon Basin. Lungfish
(Lepidosirenidae) are represented by the giant extinct
Lepidosiren megalos, similar to the smaller living L. parad-
oxa. Siluriformes (catfish) are the most abundant and
diverse group of fish and are good indicators of freshwater
environments. Cartilaginous fish are represented by the
endemic Potamotrygonidae (freshwater stingrays), the anfi-
biotic shark genera Carcharhinus, and Pristis.
Mammals are also a highly significant aspect of the ver-
tebrate assemblage. Rodents are well represented and can
be used as environmental indicators. The rodent Kiyutheri-
um orientalis (Hydrochoeridae, Cardiatheriinae), a typical
Huayquerian rodent recorded in the Solimo
˜
es Formation
as well as in Venezuela, Argentina, an d Uruguay, inhabited
areas near bodies of water like the present capivaras. Prot-
erotheres (Liptoterna), astrapotheres, glyptodons, pampat-
heres (Xenarthra, Cingulata), and ground sloths
(Mylodontidae and Megatheriidae) indicate more terrestri-
al ha bits in both browsing and grazing forms (Latrubesse
et al., 1997). The presence of Platyrrhini primates of the
families Cebidae and Atelidae indicate the existence of gal-
lery forests along the rivers.
4. Palynology of the Solimo
˜
es Formation
The first palynological data of Cenozoic age from the
Amazonas Basin were published by Daemon and Contre-
iras (1971), who suggested a Paleocene–Miocene age for
the sediments. Cruz (1984) established three palynological
zones corresponding tentatively to the Miocene, Miocene/
Pliocene, and Pliocene in cores from the CPRM/DNPM
boreholes.
Hoorn (1993) analyzes samples from boreholes 1AS-4a-
AM and 1AS-51-AM in Amazonas state near the border
with Peru, as well as bank outcrops (Fi gs. 2 and 9), and
identifies five pollen biozones for the Miocene (Fig. 10):
the Verrutricolporites and Retitricolporites zones (Early
Miocene), the Psiladipor ites–Crototricolpites zone (Early/
Middle Miocene), the Crassoretitriletes zone (Middle Mio-
cene), and the Grimsdalea zone (Middle/L ate Miocene).
We studied core samples from CPRM/DNPM borehole
1AS-32-AM (Figs. 2 and 9), located approximately
Stylocynus X X
Achlysictys X
Table 1 (continued)
‘‘Mesopotamian’’ Acre Urumaco
Pelecaniformes
Anhinga X X
Macranhinga X X
Gruiformes
Onactornis X
Andalgalornis X
Charadriiformes
Maegapaelus X
Crocodylia
Charactosuchus X X
Caiman X X X
Purusaurus X X
Melansuchus X
Mourasuchus X X X
Gryposuchus X X X
Hesperogavialis X X
Ikanogavialis X
Chelonia
Stupendemys X X
Podocnemys X X
Chelus X X
Phrynops X
Chelonoidis X
Lacertilia
Tupinambis X
The data from Acre were taken from the collections of the Laborato
´
rio de Pesquisas Paleontol-
o
´
gicas and our own data, as well as from Campbell et al. (2000) and Latrubesse et al. (1997). Data
from the Mesopotamian come from the collections of La Plata Museum of Natural Sciences (La
Fig. 8. Skull of Purusaurus brasiliensis, the largest alligatorid recorded in
the Solimo
˜
es Formation and one of the largest predators, reaching up to
15 m in length. For comparison, see the head of an Amazon living black
caiman Melanosuchus niger that reached 3.5 m in length. This cast of the
Purussaurus skull is on exhibit at the Museum of Paleontology of the
Federal University of Acre, Rio Branco, Acre, Brazil.
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 69
53.5 km SW of borehole 1AS-4a-AM studied by Hoorn
(1993). We studied 13 samples in borehole 1AS- 32-AM,
between 132 and 12 m depth below ground level, at inter-
vals of around 10 m, and identify two zones (Grimsdalea
and Asteraceae zones).
Samples for pollen analysis were also collected from out-
crops of the Solimo
˜
es Formation sediments along the Acre
River banks in the Brazil/Peru/Bolivia border area (Figs. 2
and 11). Sediment samples were treated according to the
methodology of Uesugui (1979). The preparation involved
Fig. 9. Area studied by Hoorn (1993, 1994a,b), as indicated with a square in Fig. 2. Borehole IAS 32-AM is also indicated.
Miocene zonation
of the Solimões Formation
Age
Zones
E
F
Grimsdalea
Grimsdalea/
E. Spinosus
Crassoretitriletes
D
C
Psiladiporites
Crototricolpites
Verrutricolporites
Retitricolporites
B
A
.
M./L
L.
M
iddle
MIOC
E
E
N
Early
Wells
Brazil
IAS-4a-AM
IAS-51-AM
IAS-32-AM
?
Colombia
Outcrops
Peru
Acre
Pebas formation
Barranco
da Elizete
Iquitos
Pevas
Patos
Niterói
“Terciario Amazonico”
Buenos Aires
Los Chorros
Bocanas
Pto. Caiman
Sta. Isabel
Mariñame
Argentina-
Uruguay
Ituzaingo Fm
(Lower levels) and
Kiyu Fm-
Parana Fm
?
Venezuela
Urumaco-Upper
/middle members
Bolivia
Tariquia Fm
?
Petaca Fm
Yecua Fm
Fig. 10. Correlation of wells IAS-4a AM and IAS-51-AM with outcropping sediments in Brazilian and Colombian Amazonia, according to Hoorn (1993,
1994a,b) and data herein on Acre outcrops and well IAS 32-AM. Note random correlation of Miocene deposits along the outcrops, as proposed by Hoorn.
Why small temporal differences might exist among Los Chorros, Puerto Caiman, Bocanas, and Buenos Ares inside the early Late Miocene was not
explained by Hoorn, nor are they sustained by the pollen content. The correlation of the Solimo
˜
es Formation with the Mesopotamian of Argentina and
Uruguay (lowermost levels of Ituzaingo and Kiyu formations) and the Falcon Basin in Venezuela and Tariquia Formation in Bolivia is shown.
70 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
grinding of the samples, followed by reaction with 32%
HCl and 40% HF, then separation using ZnCl
2
. A total
of 300 pollen types were counted. In addition to presenting
new palynological data, we reassess some stratigraphic and
paleoenvironmental inferences proposed previously. Nota-
bly, our analysis of the sediments along the Acre River
reveals no evidence of marine (or brackish-water) indica-
tors, such as dinoflagellate cysts, foraminiferal linings, or
mangrove assemblages, which is detrimental for the seaway
model proposed by Ra
¨
sa
¨
nen et al. (1995).
4.1. Samples from borehole 1AS 32-AM
As we already noted, the upper 132 m of borehole 1AS-
32-AM were sampled, which corresponds to the Grimsdalea
interval zone (sensu Lorente, 1986), with the uppermost
part of the borehole section corresponding to the Astera-
ceae interval zone (sensu Lorente, 1986).
Three distinct intervals can be recognized. In the lower
part, 132—48 m, the lithology consists at the base of a lig-
nite clay layer, followed by silt, sand, and lignite inclusions
(1.65–0.40 cm thick). Limestone, pyrite nodules, and plant
debris are abundant at around 55 m depth. This interval is
characterized by Grimsdalea magnaclavata (first occurrence
defines the base of the zone), with abundant C. vanraads-
hoovenii and P. pokornyi, plus Mauritiidites franciscoi,
Monoporopollenites annulatus, and D. adriennis. Other
species such as Cicatricosisporites sp., M . grandiosus, Reti-
tricolpites lorentae, Bombacacidites baculatus, Bombacaci-
dites bellus, B. muinaerum, Corsinipollenites oculusnoctis,
Verrucatosporites usmensis, Verrumonoletes sp., Verrutri-
letes sp., Psilamonoletes tibui, Psilatriletes sp., Echitriletes
muellerii, Matonisporites sp., and Polypodiaceiosporites
sp., are also present in small quantities. Lorente (1986)
defines the base of the Grimsdalea zone by the first occur-
rence of this species and the top as just below the first
occurrence of Echitricolpites spinosus. Retitricolpites loren-
tae has its first occurrence in this zone, and Bombacacidites
bellus also occurs (Hoorn, 1993), which confirms the pres-
ence of the Grimsdalea zone in this interval.
In the middle part of the borehole section, 48–25 m, the
lithology is characterized by beds of clay intercalated with
limestone. Lignite, remains of calcareous fragments, and
fossils with pyrite nodules are also found. The presence
of G. magnaclavata and the absence of C. vanraadshoovenii
suggest that this section belong to the upper Grimsdalea
zone (sensu Lorente, 1986) but above the uppermost levels
of Hoorn (1993)
. Grimsdalea sp1., E. maristellae, Proxaper-
tites tertiaria, Crototricolpites annemariae, E. estelae, and
Syncolporites anibalii also are present. However, a gap
exists between 48 and 25 m, where C. vanraadshoovenii is
absent and E. spinosus has not appeared, possibly due to
problems in the record.
Finally, the upper part occurs between 25 and 12.1 m.
This interval is characterized by clay, limestone, and sand
beds. Its top is defined by carbonaceous clay. The first
appearance of Echitricol porites spinosus, which occurs at
25 m depth, characterizes the base of Asteraceae zone,
but it is not very frequently observed (<2%). This section
is instead dominated by G. magnaclavata, D. adriennis,
P. pokornyi, Azolla sp., Magnastriatites grandiosus,
E. marist ellae, and Proxapertites tertiaria. In addition,
Grimsdalea sp1., V. usmensis, Clavatriletes sp., R. lorentae,
B. bellus, B. baculatus, B. muinaerum, Echitricolpites sp.,
Fig. 11. Riverbank outcrops with palynologic data from the Acre River. Outcrops located in area 1 of Fig. 2.
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 71
Matonisporites sp., M. annulatus, Psilatriletes sp., C.
columbianus, M. vanderhamenii, and P. tibui are found in
low quantities. Hoorn (1993) and Leite (2004) record the
appearance of E. spinosus from the Middle Miocene
(Crassoretitriletes zone), though Germeraad et al. (1968),
Lorente (1986), and Muller et al. (1987) record E. spinosus
from the upper Miocene, considering it a good stratigraph -
ic marker. Other specie s characteristic of the Late Miocene,
such as Cyathecidites annulatus, Pachydermites diederixi,
and Bom bacacidites ciriloensis, were not recorded in our
study. Cruz (1984) records Cyathecidites annulatus, Pachy-
dermites diederixi, Echitricolporites spinosus, Polypodiacei-
osporites potonei, Fenestrites spinosus, Magnastriatites
howardi, and Striasyncolpites zwardi in samples from the
Solimo
˜
es Formation, considering them characteristic of
the Late Miocene.
4.2. Samples from the banks of the Acre River
As we have noted, four localities on the Acre were inves-
tigated using palynological data (Fig. 11). At Patos and
Nitero
´
i, pollen samples and vertebrates were collected from
the same stratigraphic level. At Murici and Barranco da
Elizete, the sediments pro vided pollen but no vertebrate
fossils. The lithological sections of the surfa ce localities
are represented in Fig. 11 and described next. Palynological
diagrams appear in Fig. 12.
Murici is on the right bank of the Upper Acre River,
close to the town of Assis Brasil on the Brazil–Bolivia bor-
der. The sediments from which the samples were collected
are clays rich in organic material including lignite, approx-
imately 3 m above the low-stage water level. The outcrop is
characterized by an abundance of G. magnaclavata and the
absence of C. vanraadshoovenii and E. spinosus. In order of
abundance, the following taxa are present at Murici: G.
magnaclavata, D. adriennis, Verrucatosporites usmensis,
Psilatriletes sp., Monoporopollenites annulatus, Perisyncolp-
ites pokornyi, Verrutriletes sp., Psilatriletes sp3., and M.
grandiosus. Frequencies of up to 2% are observed for Mau-
ritiidites franciscoi, Azolla sp., Bombacacidites sp3., Retitri-
colporites sp2., R. porispectus, R. lorentae, Psilatricolporites
minimus, Retimonocolpites sp., and P. tertiaria. Frequencies
of <1% are found for Bombacacidites sp1., Retimonocolpites
sp2., Chomotriletes minor, C. columbianus, E. maristellae,
Echiperiporites sp1., Psilatriletes sp3., and Retitricolpites sp1.
The Barranco da Elizete locality is on the left bank of
the Upper Acre River. The sample, of a dark clay lens,
was taken at the low-water level during the dry season
(southern hemisphere winter). The presence of E. spinosus
and Fenestrites sp. could indicate a Late Miocene age.
The assemblage is composed of Psilatriletes sp., Verrutri-
letes sp., Verrumonoletes sp., Concavisporites sp., Echitri-
colporites spinosus, Psilatrilet es sp2., Echitricolporites
maristellae, Echiperiporites sp., Bacutriletes sp. Cicatrico-
sisporites sp., Echitrile tes sp., Matonisporites sp., Kuylispor-
ites waterbolkii, Illexpollenites sp., Polypodiaceoisporites sp.
Retitricolpites sp., Echipollenites sp., and E. estelae.
Fig. 12. Palynological diagram of the outcrops samples of the Acre River.
72 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
The sample from Patos, also on the Upper Acre River,
was collected from the base of an intraformational con-
glomerate consisting of clay balls and silt, approximately
0.5 m above the water level. This conglomerate is rich in
fossil vertebrates of Huayquerian–Mesopotamian SALMA
age; Patos is a well-known mammal locality. The palyno-
logical assemblage is composed mainly of M. annulatus
(almost 70%), followed by E. spinosus, Echitriletes sp., Fen-
estrites sp., Verrumonoletes sp., Verrutriletes sp., Psilatri-
letes sp., M. grandiosus, Azolla sp., Chomotriletes minor,
Cicatricosisporites sp., Psilatricolporites sp., Psilatriletes
sp2., Psilatriletes sp3., Retimonocolpites sp., S. catatumbus,
and Echitriletes muellerii. At frequencies of <1%, we find
Retitricolpites sp., R. lorentae, Pol ypodiaceiosporites sp.,
Polyadopollenites sp., P. pokornyi, Podocarpidites sp., and
Matonisporites sp. In this same locality, we collected
in situ seeds of Myrtaceae and Euphorbiaceae (genus
Piranhea), indicating a typic al floodplain (‘‘va
´
rzea’’)
environment.
Nitero
´
i, another well-known mammal locality, is located
on the right bank of the Lower Acre River, near the town
of Senador Guiomard in Acre. The lithology is dominated
by massive green to grey–green clayey sediments. About
90 cm from the low-water level is an intraformational con-
glomeratic clay, almost 40 cm thick, with mudballs and
fish, crocodile, and turtle remains. About 2.4 m above the
low-water level is a rich fossiliferous bed. Gypsum crystals
are disseminated in the clayey sediments and fill fractures
and fossil bones. Lignite and leaves are common in this
site. Palynological samples were collected approximately
1 m above the low-water level. E. spinosus forms <1% of
the pollen count. The assemblage includes M. annulatus,
Crototricolpites annemariae, Corsinipoll enites oculusnoctis,
Psilatriletes sp., Psilatricolpites sp., Retitricolporites sp.,
Cicatricosisporites sp., Illexpollenites sp., E. maristellae,
Verrumonoletes sp., Retimonocolpite s sp., Striatricolpites
catatumbus, Mauritiidites franciscoi, Verrutriletes sp., Reti-
triletes sp.,
Retitricolporites sp., Margocolporites venwijhei,
K. waterbolkii, Polypodiaceoisporites sp., Echiperiporites
sp., Azolla sp., Bombacacidites sp., Echitriletes muellerii,
P. herngrenii, P. tertiaria, Psilaperiporites sp., Psilatriletes
sp2., Psilatricolporites sp., Podocarpidites sp., and R.
lorentae.
4.3. Palynology and biostratigraphical context
The palynomorphs at different sites can be used to indi-
cate rough absolute ages (Fig. 13) and provide tentative
correlations of surface local ities and boreholes (Fig. 10).
Patos, Barranco da Elizete, and Nitero
´
i all represent the
same time interval in the Lat e Miocene according to the
presence of Echitricolporites spinosus that characterizes
the base of the Asteraceae zone and the absence of pollen
species that indicate Pliocene and Pleistocene ages, such
as Stephanocolpites evansii, Echitricolporites mcneillyi, and
Alnipollenites verus. This age estimate is consistent with
that from the vertebrate assemblage in the same area.
Regarding borehole IAS-32-AM, despite its proximity
to the core studied by Hoorn (1993), we observe paleoenvi-
ronmental and biostratigraphical differences. First, Zono-
costites ramonae (Rhizophora), which according to Hoorn
(1993) is abundant in samples from the Grimsdalea zone,
is not found in borehole IAS-342-AM. The association of
this species with Deltoidospora adriennis was interpreted
by Hoorn (1993) as characterizing a costal plain environ-
ment (related to Serravallian global sea level rise, see
Hoorn, 1993, 1994a,b; Haq et al., 1987). The absence of
Zonocostites ramonae and the presence of D. adriennis sug-
gest a freshwater paleoenvironment in the Grimsdalea zone
(Collinson, 2002). In Hoorn’s (1993) fig. 9, the Grimsdalea
zone persists only up to the Middle–Late Miocene bound-
ary, but we recorded E. spinosus in the upper section of
borehole 1AS-32-AM as well as in outcrops of the Rio
Acre in the Late Miocene. Therefore, a younger age than
that proposed by Hoorn (1993) applies to well 1AS-4a-
AM.
Second, we do not find C. vanraadshoovenii in any sam-
ples at depths shallower than 48 m and find E. spinosus
above 25 m. Our observations seem to agree with those
of Germ eraad et al. (1968) and Muller et al. (1987)
(Fig. 13), who note the disappearance of Crassoretitriletes
vanraadshoovenii at the base of or a little before the Aster-
aceae zone in the Caribbean. This pollen species extends to
the top of the Pleistocene in Borneo and Nigeria. Lorente
(1986) shows that C. vanradshoovenii is still alive in some
parts of the tropics.
Third, Hoorn (1993) concludes that there is no paly-
nological evidence of Late Miocene or Pliocene ages
but mentions the presence of E. spinosus in the Crasso-
retitriletes zone. Similarly, we associate E. spinosus and
Crassoretitriles with Fenestrites, which has been reported
to appear only in the Late Miocene and Pliocene (Ger-
meraad et al., 1968; M uller et al., 1987). Our observa-
tions seem to agree with the disappearance of
Crassoretitriletes vanraadshoovenii at the base or a little
before the Asteraceae zone.
The biozones established by Hoorn (1993) for western
Amazonia, notably the Crassoretitriletes (ass igned to the
Middle Miocene) and Grimsdalea (Middle–Late Miocene),
thus should be used with some caution, because the bio-
chron of the main biostratigraphic markers seems, on the
basis of the inconsistency between different reports in dif-
ferent regions, to be temporally transgressional (Fig. 13).
For example, if we use the palynological biozone criteria
of abundance/scarcity, we might conclude that some of
the Acre River outcrops are of different ages because
E. spinosus occurrences vary from a representative 8% at
Barranco da Elizete to a scarce 1% at Niteroi and none
at Murici. E. spinosus should be abundan t in the Late Mio-
cene (consistent with a Late Miocene age for Barranco da
Elizete), and its scarcity or absence would suggest an older
or younger age for Murici or Niteroi. However, Niteroi
and Patos are the most representative and important local-
ities for Huayquerian (Late Miocene) mammals. Forcing
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 73
different ages for these outcrops using the absence, pres-
ence, or scarcity of E. spinosus or Grimsdalea would thus
lead to error. Although pollen biozones have been impor-
tant for recognizing the Miocene ages of the sediments in
Amazonia, we need to improve their definitions and cali-
brations, because their current definitions do not have suf-
ficient stratigraphic sensitivity and thus cannot be used as
precise tools for separating spans of time within the Mio-
cene. Instead, they can lead to incorrect age assignments
within the Miocene and, thus, miscorrelations of the out-
crops and borehole evidence.
4.4. Paleoenvironmental inferences
According to Lor ente (1986), sporomorph assemblages
that are rich in specimens but poor in species are character-
istic of alluvial plains. This combination of characteristics
is observed in several borehole and outcrop samples. For
instance, dominance by pollen of Gramineae, as observed
at Patos, suggests an alluvial plain depositional
environment.
The pollen association recorded in the upper levels of
borehole IAS-32-AM is dominated by Grimsdalea magna-
clavata. This is not a living species; Germeraad et al.
(1968) infer it is a palm with a marked adaptability to dif-
ferent habitats. In the fossil record, this species is restricted
to the Caribbean, Venezuela, Colombia, and Brazil. A high
abundance of its pollen probably characterizes the margins
of shallow floodbasin lakes (Hoorn, 1994a) or forest ele-
ments (Wijninga, 1996). In addition, a high abundance of
P. pokornyi (Malpighiaceae), recorded in association with
Grimsdalea magnaclavata, also suggests a forest environ-
ment near the area of deposition.
In the lowermost intervals of borehole IAS-32-AM,
Crassoretitriletes vanraadshoovenii is dominant. This spe-
cies has botanical affinities with Lygodium microphylum
(synonymous with L. scandens), a climber fern with living
representatives in Guyana (botanical samples deposited in
the herbarium of the Missouri Botanical Garden) and Bra-
zil (herbarium of the INPA-National Institute of Amazo-
nian Research, Manaus, Brazil, where material collected
in Sa
˜
o Paulo state is stored). However, some claim this spe-
Fig. 13. Biochron of main palynologic biostratigraphic markers used in northern South America for the Middle and Late Miocene. Note the temporal
overlap/differences that vary among authors. Note also the different ages proposed for the Grismdalea biozone, though E. Spinosus seems characteristic of
the Upper Miocene. Sources of information: (1) Germeraad et al. (1968); (2) Silva (2002); (3) Hoorn (1993); and (4) Muller et al. (1987). Germeraad et al.
(1968) investigated the Caribbean; Lorente (1986) and Muller et al. (1987) worked in Venezuela. These localities, which are rather distant from the present
study region, provide some points of comparison. Hoorn’s (1993) work was in western Amazonia.
74 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
cies now lives only in West Africa and southeast Asia (Lor-
ente, 1986).
Swamps are indicated by the presence of C. vanraads-
hoovenii (Schizaceae), and aquatic or wet environments
are suggested by Magnastriatites grandiosus (Pteridaceae),
V. usmensis (Polypodia ceae), Psilamonoletes tibui, Deltoi-
dospora adriennis (Pteridaceae), Chomotriletes min or,
Bombacacidites baculatus (Pachira aquatica), and Azolla
sp. (Hoorn, 1993; Collinson, 2002).
Returning to the pollen collected from the outcrops
along the Acre River, Patos shows a predominance of
Monoporopollenites annulatus (70%), which appears less
abundant at Nitero
´
i (15%), indicating aquatic vegetation
(grassland in floodplains and/or floating meadows; Hoorn,
1994b).
In all four localities, spores (e.g., Echitriletes muellerii
(Sellaginellaceae?), Azolla sp., K. waterbolkii (Cyathea-
cea), Psilatriletes sp., Verrumonoletes sp., Cicatricosispor-
ites sp.) are abundant and indicate a wet or aquatic
environment. Corsinipollenites oculusnoctis (Onagraceae)
and Chomotriletes minor are also present, mainly at
Nitero
´
i, suggesting an aquatic environment. In addition,
forest elements are represented by P. pokornyi, Illexpolle-
nites sp. (Aquifoliaceae), and Multimarginites vanderham-
menii (Acanthaceae) (Germeraad et al., 1968; Hoorn,
1993; Collinson, 2002).
Overall, the predominance of both spores and pollen
indicates an aquatic environment consisting of freshwater
lakes and swamps. This inferred abundance of freshwater
lake and swamp elements supports deductions made from
the fauna. The environment inferred in Acre state and
southern Amazonas from both vertebrates and pollen con-
tent of the sediments of the Solimo
˜
es Group implies grass-
land and gallery forests along rivers, swamps, and shallow
lakes, subjected to fluctuating water levels in a tropical to
wet–dry tropical seasonal climate.
5. Correlation problems
5.1. Northern Amazonia
The outcrops in Acre were correlated by Ra
¨
sa
¨
nen et al.
(1995) with the sediments of NW Amazonia described by
Hoorn (1993, 1994a,b). As we have noted, it appears that
the chronology proposed by Hoorn (1994b), based on pal-
ynological studies of boreholes and outcrops, contains
some inconsistencies in the correlation of some outcrops
with the core sequences. Hoorn’s (1994b) five palynological
zones cover the time span between the Early Miocene and
Middle–Late Miocene (23 to 10 M a). Notably, she cor-
related the outcrop at Marin
˜
ame/Santa Isabel area in the
Caqueta
´
River (Fig. 9) with the lowermos t levels of bore-
hole 1AS-4a AM (263.5–181.8 m depth; assigned to the
Retitricolporites and Psiladiporites–Crototricolpites zones;
Early Miocene), located approximately 300 km to the
south. However, the Early Miocene was not recorded in
borehole IAS-51-AM, nearly 150 km to the east from the
typical outcrops of Marin
˜
ame/Santa Isabel area in the
Caqueta
´
River (Figs. 9 and 10). Because the Solimo
˜
es For-
mation is subhorizontally or horizontally bedded, and no
paleorelief or strong vertical displacement of faulting has
been described in this area, the topographic difference of
250 m separating the outcrop of Early Miocene sediments
at Marin
˜
ame and the inferred correlative deposits in well
IAS-4a AM, buried around 200 m deep, demand justifica-
tion (Fig. 14). The outcrops at Puerto Caiman and Buenos
Aires in the Caqueta
´
and Cotuhe
´
rivers, as well as those
along the Colombian part of the Amazon, near Marin
˜
ame,
have been correlated with the Grimsdalea zone (Middle–
Late Miocene; Hoorn, 1993) (Figs. 9 and 10). Given the
absence of concrete field evidence of paleorelief, differential
subsidence, or faulting, the lateral correlation between the
older Early Miocene sediments at Marin
˜
ame and the
Middle–Late Miocene sediments cropping out at other
localities nearby is a problem. As we noted, Hoorn
(1993) did not identify Early Miocene deposits in borehole
1AS-51-AM (Figs. 9, 10, and 14). In this borehole, the
basement was reached 167 m below the surface, and a mid-
dle Miocene age was assigned to the lowermost levels. If
the Early Miocene is not recorded in this well, as reported
by Hoorn (1993), it either was never deposited or eroded
before deposition of the Middle Miocene seq uence.
The more feasible explanation is that the Early Miocene
is not recorded in well IAS-51-AM because it is located on
the Iquitos arch. The Early Miocene sediments should rest
subhorizontally, like a plateau, and deepen generally to the
southwest, growing more deep in the direction of the depo-
center of the basin (wells IAS 4a–AM) and outcrop lateral-
ly in the border/margin of the basin to the northeast in
Colombian territory (Marin
˜
ame-Santa Isabel area). If this
proposition is correct, the Iquitos arch was an active struc-
tural barrier during the Early Miocene in the Amazon
Basin, probably acting as a forebulge or area in which we
might expect thin deposits or no deposition to that time.
However, the situation is more complex for the Late
Miocene. Why did dep ositions continue in NW Brazilian
Amazonia but not in SW Colombia? After the deposition
of the Marin
˜
ame Early Miocene sediments, part of Colom-
bian Amazonia may have acted as a positive relief during
the Middle–Late Miocene, but subsidence continued in
Brazilian Amazonia and southernmost Colombian Amazo-
nia. This scenario could account for the different ages of
the sediments but would exclude the possibility of marine
transgressions reaching western Amazonia from the Carib-
bean Sea, through the Colombian Llanos, in the Middle or
Late Miocene (cf. Hoorn, 1993, 1994b), because the north-
ernmost part of the Colombian Amazon lowlands would
suffer uplift during the Middle–early Late Miocene. So
what happened with the Iquitos arch at this time? Appar-
ently, the arch was overlapped by tertiary sediments during
the Middle Miocene–Late Miocene (150 m of Middle–Late
Miocene deposits in wells IAS-51-AM); in this case, the
forebulge area suffered drastic position and behavior
changes, suffered subsidence in the area of the Iquitos arch,
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 75
and migrated east. At present, these remain hypotheses; we
need more data to draft a more concrete structural scenar-
io, particularly for the area east of the Iquitos arch.
However, it is important to note that our palynological
data from borehole IAS-32-AM near the area described by
Hoorn (1993) suggests that Late Miocene deposition
occurred in northern Amazonia, west of the Iquitos arch
and in Acre state. The difficulties previously noted prevent
the correlation of the deposits of the Solimo
˜
es Formation
throughout Amazonia, particularly when trying to differen-
tiate units within the Miocene. To strengthen such tempo-
ral calibrations, a combined stratigraphic approach using
vertebrate paleontology is desira ble.
5.2. Southwestern Amazonia
In trying to justify an intracontinental seaway, Ra
¨
sa
¨
nen
et al. (1995) correlate the outcrop of the Solimo
˜
es Forma-
tion in Acre with the marine incursions proposed by Hoorn
(1993, 1994b) in northwestern Amazonia and oth ers in the
Chaco Basin (Marshall and Sempere, 1993; Marshall et al.,
1993) (Fig. 1A). Rasanen et al. also forced a Late Miocene
age (Serravalian–Tortonian) on the hypothetical seaway.
However, the deposit s in Acre yield a Late Miocene fossil
assemblage (Latrubesse , 1992; Latrubesse et al., 1997),
indicating Huayquerian SALMA dating of 9–6.5 Ma
(Flynn and Swisher, 1995; Cione et al., 2001). In contrast,
the marine incursions postulated for the sediments of the
Pebas Formation in NW Amazonia are dated to the Mid-
dle Miocene or early Late Miocene (older than 11 Ma;
Hoorn, 1993), indicating they are at least 2.5 Ma older than
the Acre sediments. This correlation, suggested by Ra
¨
sa
¨
nen
et al., appears incorrect, despite the difficulties noted
regarding Hoorn’s pollen ages (1993, 1994a,b).
Ra
¨
sa
¨
nen et al. (1995) suggest that the mammalian fauna
in Acre state is not reliably dated and may be Middle Mio-
cene, not Late Miocene. On the contrary, our contem pora-
neous and subsequent work has significantly strengthened
the basis for placing this fauna within the Late Miocene.
Notably, support for a Late Miocene age is strengthened
by the pollen content of the key vertebrate sites of Patos
and Niteroi, which contain Echitricolpites spinosus , consis-
Fig. 14. Another view of sediment positions and correlation in the terrain related to the sea level. The correlation between the Marin
˜
ame unit and the early
Miocene deposits of the IAS-4a represent a difference of more than 200 m, almost equal to the well depth. Note the absence of Early Miocene sediments in
well IAS-51-AM, indicating a hiatus or no deposition period in the section at around 10 Ma.
76 E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80
tent with the Huayquerian age established for the macro-
fossils collected from the area (Fig. 10). On the basis of
the faunal assemblage, the sediments in Acre can be corre-
lated with the Urumaco Formation in Venezuela, which
was deposited in a marginal environment and also is con-
sidered Huayquerian because of its fossil vertebrate con-
tent and its temporal correlation with the foraminifera
zonation of the Caribbean zone (Dias de Gamero, 1996;
Linares, 2004) (Fig. 10, Table 1).
A further difficulty regarding the connection with the
South Atlantic across Bolivia and the Parana Basin pro-
posed by Ra
¨
sa
¨
nen et al. (1995) is that this proposal corre-
lates the Acre sediments with the Yecua Formation. The
Yecua Formation in the southern Bolivian plains indica tes
the northernmost limit of the Middle Miocene transgres-
sion within the Parana Basin (Entrerrian transgression;
Marshall et al., 1993). This unit has fossil mammals from
the Chasicoan mammal age, which is Middle Miocene
(>10 Ma) (Marshall and Sempere, 1993; Marshall et al.,
1993). None of the fossil vertebrates recorded in the Yecua
Formation has been recorded in the Solimoes Formation in
SW Amazonia. However, largely correlative with the Yec-
ua Formation are the sediments of the Entrerrian trans-
gression, recorded across much of southern South
America as the Parana
´
Formation in NE Argentina and
extending into southern Brazil (as the Mioceno de Pelotas ),
Uruguay (Camacho Formation), and Patagonia (Puerto
Madryn and correlated units). Abundant and spectacular
fossils, including bivalves, gastropods, and marine mam-
mals, clearly indicate the marine nature of these sediments
(Cozzuol, 1993; Martinez and del Rio, 2002). The mini-
mum age obtained from the marine outcrops in Patagonia
was determined as approximatel y 10 Ma on the basis of
86
Sr/
87
Sr 87 analysis on mollusks (Scasso et al., 2001)
and should be around 7Ma in the Chaco–Parana Basin
(Hernandez et al., 2005). Nevertheless, new discussions
remain open about the age and nature of the marine depos-
its in southern Bolivia.
The subsequent regression phase is marked in the south-
ern Parana
´
Basin by the deposition of fluv ial sediments of
the Ituzaingo
´
Formation, possibly as a response to a fall in
sea level at the Serravalian–Tortonian boundary.
The Ituzaingo
´
Formation occurs along the Parana
´
River
in Entre Rios Province, Argentina, and the correlative
Kiyu
´
Formation in Uruguay bears a vertebrate assemblage
with strong affinities with the Acre fauna (Cione et al.,
2001; Perea et al., 1994), clearly dating from the Huayque-
rian SALMA (Fig. 10, Table 1). During the Late Miocene,
the Tariquia Formation was deposited in Bolivia, which
should correlate with the deposits described herein and
by Ra
¨
sa
¨
nen et al. (1995) in Acre. The Tariquia Formation
was deposited in a fluvial continental environment between
8 and 6 Ma (Moretti et al., 1996).
This Acre fauna thus postdates the Chasicoan mammals
found in deposits dating from the time of the marine trans-
gression, or the Middle Miocene–early Late Miocene in the
case of the Yecua Formation record. A synchronous chro-
nological record and posttransgression environment
between the fossiliferous levels of the Solimo
˜
es Formation
in SW Amazonia and the fluvial sediments of the Ituza-
ingo
´
/Kiyu
´
formations in the Parana
´
–La Plata Basin is thus
postulated (Cozzuol, 1993; Cione et al., 2001). The sedi-
ments of the Solimo
˜
es Format ion described by Ra
¨
sa
¨
nen
et al. (1995) and us in Acre thus correlate with the Late
Miocene posttrangression sediments repres ented by the
Ituzaingo
´
Formation in the Parana
´
Basin and the Urumaco
Formation in Venezuela, not with the end of Middle Mio-
cene transgression (Fig. 1B).
In conclusion, the Early and the Middle–early Late
Miocene are not recorded outcropping in SW Brazilian
Amazonia, so we cannot discuss an imaginary paleoscenar-
io to this time in the region. Additional information from
wells of the old Coal Project of CPRM and from the Ram-
o
´
n Formation, a unit of probable older tertiary age on the
border of Brazil and Peru, eventually may shed some new
light on older tertiary records in SW Brazilian Amazonia.
6. Southwestern Amazonia during the Late Miocene
In light of the available evidence, we propose a new
paleoenvironmental reconstruction for SW Amazonia dur-
ing the Late Miocene (Fig. 1B). As we have discussed,
much of the evidence of marine influences during the Mio-
cene comes from NW Amazonia. Several authors have
proposed that occasional Early–Middle Miocene marine
incursions from the Caribb ean reached as far south as
2°S (Hoorn, 1993; Vonhof et al., 1998). Stable isot ope
studies could indicate that the marine incursions, if they
existed at all, were weak, with the seawater component
diluted by freshwater (Vonhof et al., 1998). Wesselingh
et al. (2002) report mainly freshwater molluscs in the Pebas
Formation, the part attributed by palynology to the Mid-
dle Miocene of the Solimoes Formation in this region.
Also, in a more recent study by Kaandorp et al. (2006)
only freshwater mollusks were recorded in outcrops of
the upper Solimo
˜
es Basin, including some localities
described by Hoorn (1994a). Ostracods in the upper Soli-
mo
˜
es area could indicate a brackish environment
(Mun
˜
oz-Torres et al., 2006). However, ostracods found
in outcrops of the Tarauaca
´
River, near the border of
Amazonas and Acre states, indicate freshwater environ-
ments in the area too (Feijo
´
Ramos, 2006). Atypical mar-
ine fossil associations (vertebrates or invertebrates)
previously were recorded in the Amazon, but no evidence
of marine transgressions has been reported in NW Amazo-
nia during the Late Miocene. However, we recognize that
some inconsistencies remain unresolved regarding the pub-
lished pollen ages for this region (Hoorn, 1993, 1994a,b),
and some Miocene ages may be subject to future adjust-
ment once an overall regional correlation scheme has been
established (Figs. 10 and 13).
To establish the regional conditions during depo sition of
the Solimo
˜
es Formation, it is necessary to consider the evo-
lution of the northern and central Andes (Fig. 1A). The
E.M. Latrubesse et al. / Journal of South American Earth Sciences 23 (2007) 61–80 77
first influence of a rising Eastern Cordillera in Colombia
appears at around 12 Ma (Guerrero, 1997). Sediments
derived from the northern Andes, with the rich fossil fauna
of La Venta (13–11 Ma), were deposited across the Mag-
dalena Basin (La Honda Formation; Kay et al., 1997).
The evolution of SW Amazonia reflects the evolution of
the central Andes, where the Eastern Cordillera likely expe-
rienced uplift and erosion between 27 and 5 Ma (Late Oli-
gocene–end of the Miocene) (Nobret et al., 1996),
resulting in an influx of sediments to the Amazon foreland
basin, which led to the deposition of the lower part (not
exposed in Acre) of the Solimo
˜
es Group. The cratonic areas
east of the foreland basin also acted as a sediment source
(Hoorn, 1993). The fastest uplift and deformation in the
central Andes occurred in the late Miocene (e.g., Coudert
et al., 1995; Jordan et al., 1983; Sebrier et al., 1988). After
10 Ma, debris accumulated in the foreland basin, and the
sub-Andean fold-and-thrust belt developed (Gubbels
et al., 1993). We infer that the sedimentary response to these
events was the development in SW Amazonia during the
Huayquerian/Mesopotamian SALMA, marking the late
Tortonian and early Messinian stages, of a complex terres-
trial sedimentary system. At this time, SW Brazilian
Amazonia was connected directly to the Andes, and a
megadepositional system, formed by avulsive fluvial belts
entering and crossing a large floodbasin, deposited at least
the uppermost levels of the Solimo
˜
es Formation (Fig. 1B).
Large depositional systems, formed by river-like megafans
(similar to but in a wetter environment than the modern
Chaco and Indogangetic depositional systems) sourced
from the Andes, spread onto the subsiding plain formed
by shallow lakes, swamps, and fluvial belts abandoned by
avulsion. At this time, the modern Ucayali and Maran
˜
on–
Huallaga basins did not exist, and the predominant drain-
age thus was eastward from the Andes. The Divisor ranges
seem to have formed a low, positive relief but were unable
to act as an effective drainage divide, transected as they were
by the fluvial systems and surrounded but not covered by
the Late Miocene sediments (Latrubesse and Rancy, 2000).
The climate during the Late Miocene was wet tropical
with a dry season. Some lakes were probably slightly saline,
as indicated by stable isotopic analyses of molluscs (Von-
hof et al., 1998). However, aridity was weak and insuffi-
cient to produce calcareous soils (calcretes) or evaporites.
An abundant fauna, including fish, turtles, crocodiles,
and mammals, inhabited the associated rivers, swamps,
lakes, and gallery forests. The vegetation was dominated
by a palynological association indicating the presence of
freshwater lakes and tropical swamps.
7. Conclusions
New pollen data from established mammal sites in the
Brazilian states of Acre and Amazonas and the uppermost
levels of well IAS-AM-32 indicate a Late Miocene age for
the sediments cropping out in this region, consistent with
the age (Huayquerian–Mesopotamian SALMA, 9–
6.5 Ma) previously deduced for the vertebrate fauna in
these sediments. A terrestrial wetland environment is indi-
cated (Fig. 1B), represented by marshes, shallow lakes, and
canopy forest along fluvial channels, consistent with the
sedimentary facies present. The water and sediment sup-
plies for this system came from the Andes, forming a vast,
highly unstable, hyperavulsive river system or megafan sys-
tem similar to the Quaternary Chaco environment and the
Neogene fluvial systems in the Ganges plain of northern
India.
The uppermost levels of the Solimo
˜
es Formation have
been stratigraphically correlated with the Mesopotamian
beds of Argentina (lowermost levels of the Ituzaingo
´
For-
mation) and Uruguay (Kiyu Formation), as well as with
the fossiliferous Urumaco Formation from Venezuela. A
prior suggestion ( Ra
¨
sa
¨
nen et al., 1995) that these sediments
were deposited in a tidal marine or estuarine environment
is strongly refuted, because of the inconsistencies in the sea-
way environm ental interpretation and stratigraphic mis-
takes committed by those authors when they temporally
correlate the Solimo
˜
es sediments outcropping in southwest-
ern Brazilian Amazonia with sedimentary units in the Par-
ana Basin and northern Amazonia.
Acknowledgements
We thank our colleagues from the Universida de Federal
do Acre, Rio Branco – J.P. Souza Filho, A. Ranzy, R. Ne-
gri, J.C. Bocquentin, and E.G. Silva – for discussions and
many years of collaborative fieldwork. CNPq (Conselho
Nacional de Pesquisas-Brazil) provided financial support,
and CAPES (Coordenac¸a
˜
o de Aperfeic¸o
˜
amento de Nı
´
vel
Superior, Brazil) funded a research fellowship for S. Silva.
We also thank CPRM (Geological Survey of Brazil) for
providing samples for pollen analyses and Marı
´
a Ine
ˆ
s Feijo
´
Ramos from Museu Paraense Emilio Goeldi, Belem, for
fossil invertebrate identifications. We especially thank Ra-
jiv Sinha, Rick Madden, David Bridgland, and Rob West-
away for critical suggestions that improved the manuscript.
This paper is a contribution to the IGCP 518 project ‘‘Flu-
vial sequences as evidences for landscape and climatic evo-
lution in the Late Cenozoic’’.
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