Neotropics provide insights into the emergence of New World monkeys: new dental evidence from the late Oligocene of Peruvian Amazonia

ADNET, S.; RAMDARSHAN, A.; ANTOINE, P.-O.; ALTAMIRANO SIERRA, A. J.; SALAS-GISMONDI, R.; MARIVAUX, L.; PUJOS, F.; TEJADA LARA, J.

JOURNAL OF HUMAN EVOLUTION

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2016 vol. 97 p. 159 - 175

0047-2484

Recentfield efforts in Peruvian Amazonia (Contamana area, LoretoDepartment) have allowed for the discovery of a fossilprimate-bearing locality (CTA-61), dating from the late Oligocene(ca. 26.5 Ma; Chambira Formation). In this paper, we analyze theprimate material, which consists of two isolated upper molars. Thismaterial is admittedly limited, but the morphology of these teeth issomewhat singular, which allows us to describe a new medium-sizedplatyrrhine monkey: Canaanimicoamazonensisgen. et sp. nov. In addition to the recent discovery of Perupithecusucayaliensis,a primitive anthropoid taxon of African affinities from the latestEocene or early Oligocene of Peruvian Amazonia (Santa Rosa), thediscovery of Canaanimicoadds to the evidence that platyrrhines were well-established in theAmazonian Basin during the Paleogene. We have performed a cladisticassessment of the dental evidence in order to investigate thephylogenetic position of Canaanimicoin a high-level platyrrhine phylogeny. Our results show that neitherone of the early Miocene Patagonian taxa (Homunculus,Carlocebus,Soriacebus,Mazzonicebus,Dolichocebus,Tremacebus,and Chilecebus),nor the late Oligocene Bolivian Branisellaandthe Peruvian Canaanimico,is nested within a crown platyrrhine clade. All these early taxa areclosely related and considered here as stem Platyrrhini. Canaanimicois nested within the Patagonian Soriacebinae, and more particularlyclosely related to Soriacebus,thereby extending back to 26.5 Ma the soriacebine lineage. Given thelimited dental evidence, it is difficult to assess if Canaanimicowas engaged in a form of pitheciine-like seed predation as it isobserved in Soriacebusand Mazzonicebus,but dental microwear patterns recorded on one upper molar indicatethat Canaanimicowas possibly a fruit and hard-object eater. If Panamacebus,a recently discovered stem cebine from the early Miocene of Panama,indicatesthat the crown platyrrhine radiation was already well underway by theearliest Miocene, Canaanimicoindicates in turn that the ?homunculid? radiation(as a part of the stem radiation) was already well underway by thelate Oligocene. These new data suggest that the stem radiation likelyoccurred in the Neotropics during the Oligocene (as Canaanimicosuggests), and that several stem lineages independently reachedPatagonia during the early Miocene. Finally, we are still faced to a?layered? pattern of platyrrhine evolution, but entirelyrevisited in terms of timing of cladogenesis. If the crownplatyrrhine radiation most likely occurred in the Neotropics at leastduring the earliest Miocene, it was apparently concomitant with thediversification of the latest stem forms in Patagonia.