Biogeochemical and Craniometric Investigation of Dietary Ecology, Niche Separation, and Taxonomy of Plio-Pleistocene Cercopithecoids From the Makapansgat Limeworks Nicolaas H. Fourie, 1,2 * Julia A. Lee-Thorp, 1,3 and Rebecca Rogers Ackermann 1 1 Department of Archaeology, University of Cape Town, Cape Town, South Africa 2 Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 3 Department of Archaeological Sciences, University of Bradford, Bradford, UK KEY WORDS stable isotopes; trace elements; enamel; craniofacial morphology; Makapansgat ABSTRACT Three sympatric fossil cercopithecoid genera (Cercopithecoides, Parapapio, and Theropithecus) occur in Members 3 and 4 at the Makapansgat Lime- works hominin locality, South Africa, and their presence in a single ecosystem suggest a certain degree of ecologi- cal and/or dietary differentiation between taxa. Here, we explore the extent of dietary niche separation amongst these taxa using stable isotope ( 13 C/ 12 C, 18 O/ 16 O) and trace-element (Sr, Ba, Ca) analyses of fossil tooth enamel. In particular we searched for evidence of subtle niche separation between the more closely related, mor- phologically similar taxa of the genus Parapapio, as uncertainties exist around their taxonomy and taxo- nomic identification. Given these uncertainties, cranio- metric analyses were also performed to ground the die- tary interpretations in a morphological context. The results found no clear taxonomic signal in the craniomet- ric data for the Parapapio sample, and further indicate that this sample was no more variable morphologically than a single, geographically circumscribed, extant chacma baboon sample. In contrast, two overlapping die- tary ecologies were found within this same Makapansgat Parapapio sample. Additionally, two widely differing die- tary ecologies were found within the Cercopithecoides williamsi sample, while results for Theropithecus darti indicate a predominantly C 4 diet. Hence, although bio- geochemical dietary indicators point towards distinct die- tary ecologies within and between fossil genera at Maka- pansgat, within the genus Parapapio disjunctions exist between the dietary categories and the taxonomic assignment of specimens. Am J Phys Anthropol 135:121– 135, 2008. V V C 2007 Wiley-Liss, Inc. A rich array of primate taxa are represented in the Plio-Pleistocene deposits of the South African karstic cave sites. Thus far, all recovered fossil primate speci- mens from South African Plio-Pleistocene sites are thought to belong to the family Cercopithicidae. Two sub-families, Cercopithicinae and Colobinae, are repre- sented by four genera and up to 12 species, and one ge- nus and one species, respectively (Freedman, 1957; Brain, 1981; Delson, 1992, 1993). All the South African Plio-Pleistocene Cercopithicinae genera belong to the tribe Papionini (Freedman, 1957; Brain, 1981; Delson, 1992, 1993). During this time, sympatry/parapatry was common, with up to five papionin taxa and one colobine taxon sympatric/parapatric at some sites (Freedman, 1970). Yet at the same time there is limited morphologi- cal evidence for dietary/niche specialization. No modern analogue to this situation exists among extant papionin taxa. Most extant members of this tribe in Africa are medium body-sized terrestrial primates. There are currently far fewer extant papionin taxa in Africa than there were in the Plio-Pleistocene, and these are widely distributed across the continent; few are truly sympatric or even parapatric. Only Papio h. hamadryas and Theropithecus gelada co-occupy the same region, facilitated by distinct niche separation and specific die- tary specialization on the part of T. gelada (Dunbar and Dunbar, 1974). Some Papio subspecies are parapatric (Zinner et al., 2001), and in areas of parapatry, species borders are either maintained or hybrid zones develop (Nagel, 1970, 1973; Kummer, 1971; Phillips-Conroy and Jolly, 1981; Alberts and Altmann, 2001). This unusual ecological situation—abundant sympa- try/parapatry combined with limited morphological evi- dence for niche separation—is exemplified at the Plio- cene hominin locality of Makapansgat Limeworks in the Limpopo Province of South Africa. Here, five different fossil cercopithecoid taxa are thought to have been sym- patric/parapatric. One is a colobine, while four taxa were papionins, of which three (genus: Parapapio) appear to have been very closely related. How did so many primate taxa manage to cohabit in the same environment, which Grant sponsors: National Research Foundation of South Africa, Paleo-Anthropology Scientific Trust, University of Cape Town. *Correspondence to: Nicolaas Hofmeyer Fourie, Department of Anthropology, Center for the Advanced Study of Human Paleobiol- ogy, 2110 G Street, NW, Washington, DC 20052. E-mail: nfourie@gwu.edu Received 10 January 2007; accepted 20 July 2007 DOI 10.1002/ajpa.20713 Published online 16 October 2007 in Wiley InterScience (www.interscience.wiley.com). V V C 2007 WILEY-LISS, INC. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 135:121–135 (2008)