An eosimiid primate of South Asian affinities in the Paleogene of Western Amazonia and the origin of New World monkeys

ANTOINE, PIERRE-OLIVIER; KERBER, LEONARDO; ALVIM, ANDRÉ M. V.; ADAMI-RODRIGUES, KAREN; NEGRI, FRANCISCO R.; CONDAMINE, FABIEN L.; VENTURA SANTOS, ROBERTO; BISSARO, MARCOS C.; MARIVAUX, LAURENT; STUTZ, NARLA S.; PUJOS, FRANÇOIS; HSIOU, ANNIE S.; RIBEIRO, ANA MARIA

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Lugar: Washington DC, USA; Año: 2023 vol. 120

0027-8424

Recent fossil discoveries in Western Amazonia revealed that two distinct anthropoidprimate clades of African origin colonized South America near the Eocene/Oligocenetransition (ca. 34 Ma). Here, we describe a diminutive fossil primate from BrazilianAmazonia and suggest that, surprisingly, a third clade of anthropoids was involved in thePaleogene colonization of South America by primates. This new taxon, Ashaninkacebussimpsoni gen. et sp. nov., has strong dental affinities with Asian African stem anthro-poids: the Eosimiiformes. Morphology-based phylogenetic analyses of early Old Worldanthropoids and extinct and extant New World monkeys (platyrrhines) support rela-tionships of both Ashaninkacebus and Amamria (late middle Eocene, North Africa)to the South Asian Eosimiidae. Afro-Arabia, then a mega island, played the role of abiogeographic stopover between South Asia and South America for anthropoid primatesand hystricognathous rodents. The earliest primates from South America bear littleadaptive resemblance to later Oligocene-early Miocene platyrrhine monkeys, and thescarcity of available paleontological data precludes elucidating firmly their affinities withor within Platyrrhini. Nonetheless, these data shed light on some of their life historytraits, revealing a particularly small body size and a diet consisting primarily of insectsand possibly fruit, which would have increased their chances of survival on a naturalfloating island during this extraordinary over-water trip to South America from Africa.Divergence-time estimates between Old and New World taxa indicate that the trans-atlantic dispersal(s) could source in the intense flooding events associated with the latemiddle Eocene climatic optimum (ca. 40.5 Ma) in Western Africa.