New Paleocene skeletons and the relationship of plesiadapiforms to crown-clade primates

doi:10.1073/pnas.0610579104

New Paleocene skeletons and the relationship of plesiadapiforms to crown-clade primates

*Florida Museum of Natural History, University of Florida, P. O. Box 117800, Gainesville, FL 32611;
^‡Department of Anthropology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB, Canada, R3B 2E9;
^§Department of Anatomical Science, Stony Brook University, Stony Brook, NY 11794-8081;
^¶Department of Anthropology, Yale University, P. O. Box 208277, New Haven, CT 06520; and
^‖Division of Vertebrate Zoology, Peabody Museum of Natural History, Yale University, New Haven, CT 06520

Communicated by Alan Walker, Pennsylvania State University, University Park, PA, November 30, 2006 (received for review December 6, 2005)

Abstract

Plesiadapiforms are central to studies of the origin and evolution of primates and other euarchontan mammals (tree shrews and flying lemurs). We report results from a comprehensive cladistic analysis using cranial, postcranial, and dental evidence including data from recently discovered Paleocene plesiadapiform skeletons (Ignacius clarkforkensis sp. nov.; Dryomomys szalayi, gen. et sp. nov.), and the most plesiomorphic extant tree shrew, Ptilocercus lowii. Our results, based on the fossil record, unambiguously place plesiadapiforms with Euprimates and indicate that the divergence of Primates (sensu lato) from other euarchontans likely occurred before or just after the Cretaceous/Tertiary boundary (65 Mya), notably later than logistical model and molecular estimates. Anatomical features associated with specialized pedal grasping (including a nail on the hallux) and a petrosal bulla likely evolved in the common ancestor of Plesiadapoidea and Euprimates (Euprimateformes) by 62 Mya in either Asia or North America. Our results are consistent with those from recent molecular analyses that group Dermoptera with Scandentia. We find no evidence to support the hypothesis that any plesiadapiforms were mitten-gliders or closely related to Dermoptera.

Footnotes

^†To whom correspondence should be addressed. E-mail: jbloch{at}flmnh.ufl.edu
Author contributions: J.I.B., M.T.S., D.M.B., and E.J.S. designed research, performed research, analyzed data, and wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0610579104/DC1.
Abbreviation:

UM,

University of Michigan Museum of Paleontology.