New Fossil Cercopithecoids from the Late Miocene of As Sahabi, Libya

A preliminary revision of the fossil cercopithecoids of As Sahabi is presented based on a well-preserved right half-mandible (1P25C) with minimally worn P3-M3 and a left distal humerus (514P28A) collected in 2007. The molar teeth of 1P25C are distinguished from similarly-aged Macaca libyca (Wadi Natrun, Egypt), cf. Macaca sp. (Menacer, Algeria), and cf. Macaca sp. (Casablanca, Spain) in having M2s that are smaller, squarer, and more flared buccally. The As Sahabi papionin is distinguishable from Parapapio lothagamensis in having a less elongated and more steeply oriented mandibular symphysis, although the two monkeys share with M. libyca the presence of a P3 metaconid. Differences in size between 1P25C and some of the previously collected papionins are here attributed to dental size sexual dimorphism, although the future discovery of new material might lead to recognition of two moderately small papionins from the site. The As Sahabi papionin belongs to a new species of either Parapapio or Macaca. A newly discovered distal humerus from As Sahabi exhibits clearly cercopithecine and terrestrial features, including a strongly retroflexed medial epicondyle. It may well belong to the same species as 1P25C. A previously collected distal humerus from As Sahabi 10P61A appears to be colobine due to its well-developed lateral trochlear keel and capitulum. None of the other postcrania can clearly be assigned to subfamily due to their poor preservation. Previously collected teeth from As Sahabi all exhibit lower cusp relief and greater buccal flare than is observed in modern colobines. Given that fossil papionins from this time range have greater occlusal relief than extant cercopithecines, it is possible that only papionins are represented in the As Sahabi dental sample. Such a monkey might have had an eclectic, but predominantly frugivorous diet. Brenda R. Benefit, Department of Sociology and Anthropology, New Mexico State University, Las Cruces, New Mexico 88003, U.S.A., [email protected] Monte McCrossin, Department of Sociology and Anthropology, New Mexico State University, Las Cruces, New Mexico 88003, U.S.A., [email protected] Noel T. Boaz, International Institute for Human Evolutionary Research, Integrative Centers for Science and Medicine, 2640 Takelma Way, Ashland, Oregon 97520, U.S.A., [email protected], and Department of Anatomy, Ross University School of Medicine, P.O. Box 266, Portsmouth Campus, Roseau, Commonwealth of Dominica, [email protected] Paris Pavlakis, Department of Historical Geology – Paleontology, Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupoli Zografou, 157 84 Athens, Greece, [email protected] BENEFIT, ET AL. GARYOUNIS SCIENTIFIC BULLETIN