Santa Rosa (LACM Loc. 6289), Peru


Fundort: Santa Rosa (LACM Loc. 6289), Peru, Departamento de Ucayali, Peru
Taxon: Perupithecus ucayaliensis
Fossilien und Beschreibung der Fundstelle:
Macrofossils,mesofossils, Either latest Eocene or earliest Oligocene (Seiffert et al. 2020). Campbell et al. (2021). The Santa Rosa fossil locality in eastern Perú produced the first Paleogene vertebrate fauna from the Amazon Basin, including the oldest known monkeys from South America. This diverse paleofauna was originally assigned an Eocene age based largely on the stage of evolution of the site’s caviomorph rodents and marsupials. Here, we present detrital zircon dates that indicate that the maximum composite age of Santa Rosa is 29.6 ± 0.08 Ma (Lower Oligocene), although several zircons from Santa Rosa date to the Upper Oligocene. The first appearance datum for Caviomorpha in South America is purported to be the CTA-27 site in the Contamana region of Perú, which is hypothesized to be ∼41 Ma (Middle Eocene) in age. However, the presence of the same caviomorph species and/or genera at both CTA-27 and at Santa Rosa is now difficult to reconcile with a >11-My age difference. To further test the Middle Eocene age estimate for CTA-27, we ran multiple Bayesian tip-dating analyses of Caviomorpha, treating the ages of all Paleogene species from Perú as unknown. These analyses produced mean age estimates for Santa Rosa that closely approximate the maximum 29.6 ± 0.08 Ma composite date provided by detrital zircons, but predict that CTA-27 is much younger than currently thought (∼30 Ma). We conclude that the ∼41 Ma age proposed for CTA-27 is incorrect, and that there are currently no compelling Eocene records of either rodents or primates in the known fossil record of South America., Moderately indurated massive clays and mudstones, with occasional bedding visible. Thin horizons a few centimeters thick of unconsolidated, variously colored fine sand of mixed composition are frequently encountered. Also frequently encountered are calcareous and hematitic conglomeratic lenses, the latter appearing to replace the former.
Geschätztes Alter
der Fundstelle:
zwischen 28,1 und 33,9 Millionen Jahre aus der Yahuarango Formation in Peru
Geologie, Sratigraphie Rupelian / Rupelian / Yahuarango
Koordinaten: 9° 29 ' 39 '' S, 72° 45 ' 48 '' W

Literatur

M. Bond, M. Tejedor, K. E. Campbell, L. Chornogubsky, N. Novo, F. Goin 2015, Eocene primates of South America and the African origins of New World monkeys. Nature. 520, p. 538 - 541, DOI: doi:10.1038/nature14120

Systematik

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