LOCOMOTOR ADAPTATIONS OF FOSSIL PLATYRRHINES

Postcranial remains of extinet platyrrhines are now known from early and middle Miocene sites in Argentina, middle-to-late. Miocene sites in Colombia, and several late Pleistocene and recent caves in the Greater Antilles. While all of these fossils retain some primitive traints from their common platyrrhine ancestor, which most likely was a generalized, arboreal quadrupedal monkey, each has altered in some distinctive ways. Several specimens from Argentina suggest monkeys that engaged in a slightly increased frequency of leaping, but another indicates a monkey retaining a primarily quadrupedal mode of locomotion accompanied by increased climbing behaviors. The skeleton ofCebupithecia from Colombia indicates a monkey with a mixed behavioral repertoire, as in the extantPithecia, including a greater emphasis on non-horizontal supports and well-developed adaptations for leaping as well as for more suspensory or climbing behaviors. The specimens from the West Indies are difficult to interpret, although two exhibit some features which might be interpreted as suggesting an increased tendency to leaping. Reconsideration of the polarity of traits in light of recent analyses of parapithecid fossils indicates most if not all hard tissue traits previously believed to be platyrrhine synapomorphies are in fact ancestral anthropoid traits. Thus, it is not possible at present to determine with certainty if any particular fossil, either from South America or elsewhere, was a member of the Platyrrhini. © 1989 Academic Press Limited.