A 60-million-year Cenozoic history of western Amazonian ecosystems in Contamana, eastern Peru

ANTOINE, P. O.; ABELLO, M. A.; ADNET, S.; SIERRA, A.J.; BABY, P.; BILLET, G.; BOIVIN, M.; CALDERON, Y.; CANDELA, A. M.; CHABAIN, J.; CORFU, F.; CROFT, D.D.; GANERØD, M.; JARAMILLO, C.; MARIVAUX, L.; NAVARRETE, R.E.; ORLIAC, N.J.; PARRA, F.

GONDWANA RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 31 p. 30 - 59

1342-937X

We provide a synopsis of ~60million years of life history in Neotropical lowlands, based on a comprehensive survey of the Cenozoic deposits along the Quebrada Cachiyacu near Contamana in PeruvianAmazonia. The 34 fossilbearing localities identified have yielded a diversity of fossil remains, including vertebrates,mollusks, arthropods, plant fossils, and microorganisms, ranging from the early Paleocene to the lateMiocene--Pliocene (N20 successive levels). This Cenozoic series includes the base of the Huchpayacu Formation (Fm.; early Paleocene; lacustrine/ fluvial environments; charophyte-dominated assemblage), the Pozo Fm. (middle + -late Eocene; marine then freshwater environments; most diversified biomes), and complete sections for the Chambira Fm. (late Oligocene-late early Miocene; freshwater environments; vertebrate-dominated faunas), the Pebas Fm. (late early to early late Miocene; freshwater environments with an increasing marine influence; excellent fossil record), and Ipururo Fm. (late Miocene--Pliocene; fully fluvial environments; virtually no fossils preserved). At least 485 fossil species are recognized in the Contamana area (~250 -plants-, ~212 animals, and 23 foraminifera). Based on taxonomic lists from each stratigraphic interval, high-level taxonomic diversity remained fairly constant throughout themiddle Eocene-Miocene interval (8-12 classes), ordinal diversity fluctuated to a greater degree, and family/species diversity generally declined, with a drastic drop in the early Miocene. The Paleocene--Pliocene fossil assemblages from Contamana attest at least to four biogeographic histories inherited from (i) Mesozoic Gondwanan times, (ii) the Panamerican realm prior to (iii) the time of South America-s