Doctoral Dissertation Improvement: Evolution of Cercopithecoid Locomotion: A Morphometric, Phylogenetic, and Character Mapping Approach

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

The results of this dissertation will provide a new hypothesis for the process by which locomotion evolved in Old World Monkeys. The dataset to be collected is extensive and includes four postcranial elements of 49 species. Data will be made accessible online to other researchers after completion of the dissertation. An online database will allow access to people who may not have the resources to collect such data on their own, such as undergraduates at small institutions or students in developing countries. The research also incorporates undergraduates and is training a female scientist. The Old World monkeys (OWMs)- monkeys that are distributed in Africa and Asia - are unique among primates for having several ground-dwelling, or terrestrial, species across many lineages. Even extant lineages that are almost strictly tree-dwelling, or arboreal, have highly terrestrial members in their fossil record. Therefore, the ancestor of OWMs is most commonly thought to have been at least partly terrestrial, with many groups secondarily evolving arboreal behavior. Support for this conclusion has been identified in the fossil species Victoriapithecus, a close relative of living OWMs that exhibits many traits thought to be adaptive for terrestriality. However, the process by which OWM locomotion evolved (i.e. the timing and number of locomotor transitions) remains unclear. Thus, the aim of this dissertation is to test the hypothesis that OWMs are ancestrally terrestrial, and to determine when and how many times locomotor transitions occurred. To accomplish this goal, measurements will be taken on four postcranial elements, the humerus, femur, astragalus, and calcaneus, of a diverse sample of living and fossil OWMs at several domestic and international museums. Statistical methods used will seek to discriminate arboreal and terrestrial species based on differences in their postcranial elements. The benefit of such an analysis is that fossil species, for which the locomotor mode is unknown, can be assigned to a group by the analysis providing the most likely locomotor behavior of the fossil. Measurements will then be mapped onto a phylogeny, a tree of proposed relationships among species, of living and fossil species to determine the most likely locomotor mode of the ancestor of OWMs.