Fossils of
Aotus dindensis were discovered in 1986 in the
Honda Group, that has been dated to the
Laventan, about 12.5 to 12.1 Ma. The species is considered the oldest member of
Aotus, recognised for the almost identical mandibular and dental morphology. It may be the ancestor of the extant
Aotus species of South America, though other authors consider the species a synonym of
Mohanamico. The material consists of a left hemimandible, a left maxillary fragment preserving roots and lingual half of M3. A body mass of has been estimated for
Aotus dindensis. The teeth of
Aotus dindensis show a tendency for sexual dimorphism, which is degenerate in modern
Aotus species. The species itself seems to have been nocturnal, but it is believed that the characteristics of its diurnal ancestors remained. The locomotion of
Aotus,
Callicebus,
Cebupithecia and the
Argentinian genus
Dolichocebus has been described as primarily
quadrupedal with some leaping. The Early Miocene origin for the genus
Aotus is the longest of primates, with only
Macaca traceable to the
Late Miocene, approximately eight million years ago.
Habitat The Honda Group, and more precisely the "Monkey Beds", are the richest site for
fossil primates in South America. It has been argued that the monkeys of the Honda Group were living in habitat that was in contact with the
Amazon and
Orinoco Basins, and that La Venta itself was probably seasonally dry forest. From the same level as where
Aotus dindensis has been found, also fossils of
Cebupithecia,
Micodon,
Mohanamico,
Saimiri annectens,
Saimiri fieldsi and
Stirtonia tatacoensis have been uncovered. == See also ==