RESUMEN
A previously unidentified middle Miocene primate from the La Venta deposits of Colombia is intermediate between squirrel monkeys (Saimiri) and callitrichines (marmosets and tamarins) in the morphology of the lower molars, mandible, and talus. Laventiana annectens is closely related to Saimiri and to Cebus (capuchin monkeys) yet resembles the probable callitrichine morphotype, demonstrating that archaic relatives of a Saimiri-like stock were suitable structural ancestors for the enigmatic callitrichines. Laventiana is also more primitive than Saimiri (= Neosaimiri) fieldsi from the same fauna, further increasing the likelihood that the latter is a lineal ancestor of modern squirrel monkeys.
Asunto(s)
Evolución Biológica , Callitrichinae/clasificación , Cebidae/clasificación , Animales , Colombia , Fósiles , Mandíbula/anatomía & histología , Saimiri/clasificación , Diente/anatomía & histologíaRESUMEN
Knowledge of the evolutionary history of living New World anthropoids is limited by a relatively poor fossil record. The discovery in 1986 of a new fossil monkey from the middle Miocene deposits of La Venta, Colombia, 12-15 million years ago (Myr BP), is the first example of a living New World monkey genus appearing in Tertiary rocks. Including anatomical evidence of the dentition and facial skull, it provides an unambiguous link between a Neogene fossil and the owl monkey, Aotus, the only modern crepuscular-nocturnal anthropoid primate. This new form brings to three the number of La Venta fossil monkeys which preserve excellent dentitions sharing extensive similarities with modern genera. All of these species are potentially ancestral to their extant relatives. The La Ventan Aotus is additional support for the idea that the modern platyrrhine radiation includes long-lived genera or generic lineages, some of which may be traceable to the early Miocene, 20 Myr BP.