Comparative anatomy, ontogeny, evolution and phylogeny of primates, with special attention to the phylogenetic position of Tarsius, the relationships of hominoids, and the muscular variations of modern humans

Abstract

In this presentation we report the results of the first comprehensive cladistic analysis based on muscular characters that addresses the relationships among the major groups of living primates and taxa such as tree‐shrews and colugos (‘flying lemurs'). This analysis is based on information obtained from a review of the literature and from dissections of more than 50 specimens of various primate and non‐primate taxa. The genera included in the analysis were: Rattus, Tupaia, Cynocephalus, Lemur, Propithecus, Loris, Nycticebus, Tarsius, Callithrix, Pithecia, Aotus, Saimiri, Macaca, Papio, Cercopithecus, Colobus, Hylobates, Pongo, Gorilla, Pan and Homo. The cladistic analysis was based on 208 characters concerning the head, neck, pectoral and upper limb muscles of these taxa, using Nona & Winclada 2002. The relationships among the taxa in the most parsimonious trees obtained (L=382; RI=0.53; CI=0.65) largely conform to those supported by recent molecular studies: the Primates, Strepsirrhini, Lemuriformes, New World monkeys, Old World monkeys, the subfamily Cercopithecinae and the Hominoidea are monophyletic groups, and there is strong support for the following relationships among hominoids: [Hylobates, [Pongo, [Gorilla, [Pan, Homo]]]]. Our study revealed that, regarding its muscles, Tarsius is one of the most peculiar primates, displaying some plesiomorphic (e.g., the presence of a distinct muscle spinotrapezius) and derived (e.g., the presence of two series of contrahentes in the hand and of the facial muscle zygomatico‐auricularis) features that are rarely seen in other living primates. We will examine the phylogenetic, evolutionary and medical implications of our data, and discuss the use of myological, molecular and osteological characters in phylogenetic reconstructions.Grant Funding Source: Mathers Foundation, GW Signature Program