Fossil deposits dated to the Eocene (approx. 55 million years ago) have yielded the earliest unequivocal members of our own order of mammals. The source of these primitive primates has traditionally been thought to lie among the Plesiadapiformes, an archaic group of mammals with primate-like teeth that date to the Paleocene and Eocene. Recent work looking only at non-dental traits has suggested that some members of the plesiadapiform cluster are more closely related to the modern Indonesian group of gliding mammals, the Dermoptera, than to the primates. This hypothesis leaves the source of origin of our own order as a matter of debate.
This project seeks to reevaluate the position of the Plesiadapiformes using contemporary systematic techniques. Data will be collected on all available anatomical regions, and for all plesiadapiform groups. The goals of this study include the elucidation of interfamilial relations within the Plesiadapiformes, and the clarification of the precise phylogenetic relationship of plesiadapiform families to undoubted primates, dermopterans, bats, tree shrews, and a few extinct fossil groups (Mixodectidae and Plagiomenidae). Stratigraphic information will also be incorporated into the analysis, to investigate the importance of the relative ordering of specimens through time to the elucidation of evolutionary relationships. This study will be the first to include all sources of information across a broad enough range of taxa to answer the questions surrounding the systematics of the Plesiadapiformes, and to clarify the events at the base of the order Primates.
