Skeletal and dental morphology supports diphyletic origin of baboons and mandrills

Skeletal and dental morphology supports diphyletic origin of baboons and mandrills

John G. Fleagle*,† and
W. Scott McGraw‡

^*Department of Anatomical Sciences, School of Medicine, Health Sciences Center, State University of New York, Stony Brook, NY 11794-8081; and ^‡Department of Anatomy, New York College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568

Communicated by David Pilbeam, Harvard University, Cambridge, MA (received for review July 30, 1998)

Abstract

Numerous biomolecular studies from the past 20 years have indicated that the large African monkeys Papio, Theropithecus, and Mandrillus have a diphyletic relationship with different species groups of mangabeys. According to the results of these studies, mandrills and drills (Mandrillus) are most closely related to the torquatus–galeritus group of mangabeys placed in the genus Cercocebus, whereas baboons (Papio) and geladas (Theropithecus) are most closely related to the albigena–aterrimus mangabeys, now commonly placed in the genus Lophocebus. However, there has been very little morphological evidence linking mandrills on the one hand and baboons and geladas on the other with different groups of mangabeys. In a study of mangabey locomotion and skeletal anatomy, we have identified features of the postcranial skeleton and the dentition that support the molecular phylogeny and clearly link mandrills with Cercocebus and Papio with Lophocebus. Moreover, the features linking Cercocebus and Mandrillus accord with ecological studies of these species indicating that these two genera are a cryptic clade characterized by unique adaptations for gleaning insects, hard nuts, and seeds from the forest floor.