Mammalian Biogeography and Anthropoid Origins

Abstract

The continuity of phylogenetic descent requires that sister taxa originate in the same place and at the same time. Resolving phylogenetic relationships can therefore aid in reconstructing remote paleobiogeographic events. The order Primates is hierarchically nested within an exclusively Asian branch of the mammalian family tree, suggesting that Primates originated in Asia. Likewise, an Asian origin for Anthropoidea is supported by the geographic distributions of its sister group (Tarsiiformes) and various stem anthropoid taxa (Eosimiidae and Amphipithecidae). Although an African origin for Primates and/or Anthropoidea has been advocated repeatedly in the past, potential sister groups for either Primates or Anthropoidea are conspicuously lacking from the living and fossil biotas of that continent. The dispersal history of Malagasy lemurs and South American platyrrhines demonstrates that primate dispersal into new terrains often sparks adaptive radiation and morphological innovation. The precocious (Paleocene) dispersal of basal anthropoids from Asia to Africa may have instigated an adaptive radiation that yielded the modern anthropoid bauplan.