RHINOCEROSES FROM THE PLIOCENE OF NORTHWESTERN KENYA DICK A. HOOiJER^ AND BRYAN PATTERSON Abstract. A large brachypotherine, Brachypo-thcrium lewisi sp. nov., is described from Ldtha-gam-1; it is the last recorded member of the group. The genus has been present in Africa since the early Miocene and presumably im-migrated from Eurasia somewhat before that time. Whether or not tlu^ African and Eurasian forms thereafter evolved in parallel is imcertain, but B. Icwi.si could hu\(' descended from the early Miocene B. siiowi (Fourtau) of Egypt. Frag-incntar>-remains from Ngorora and Sahabi are identified as B. sp. cf. B. lewisi. An upper molar from Lotliagam-1 is referable to CcratotJu'iiuiii and is the earliest record of the genus. This tooth is indistinguishable from those of specimens fomid in the later Kanapoi and Ekora sediments. C. pmecox sp. nov. is based on this material. Frag-ments from the Mursi and the Chemeron (locality J. M. 507), previously identified as C. simiim, are reassigned as C. sp. cf. C. praecox. The new spe-cies shows decided resemblances to Diceros, indi-cating diat the white rhinoceroses dixerged from the black during Pliocene time. Apart from the European Pontian D. pacJiygnatJius (Wagner), the scantily recorded history of the Diceros group is wholh African. Quaternary specimens of D. Incornis and C. simiim simum are recorded in an Appendix. INTRODUCTION Paleontological expeditions to Kenya from this Museum diseovered and worked Pliocene deposits in southeastern Turkana District during the years 1965 to 1968. These deposits, Kanapoi (Patterson, 1966), Lothagam Hill and Ekora (Patterson, Bchrensmeyer and Sill, 1970), have yielded a variet\' of vertebrates and molluscs, in-^ Rijksmuseum van Natuurlijke Historie, Leiden, Netherlands. eluding the rhinocerotid remains here re-ported upon. Two rhinoceroses are now known from Lothagam-1: a large BmcJu/potherium, represented 1)y two incomplete skulls, two lower jaws, jaw fragments, isolated teeth, an atlas and portions of a femur, and an early form of Cerafotherium, known from a single incomplete upper molar. This is the only specimen in the Lothagam col-lection to reveal the presence of any relative of the living African forms. The Kanapoi and Ekora collections contain three incomplete skulls, three incomplete jaws, xarious teeth, and a humerus of a Ceratotherium that is inseparable on the exidence from the one occurring at Loth-agam; it is less advanced than C. simum (Burchell) in skull structure and resembles Diceros hicornis (L.) in dental characters. Specimens of Brachijpothcrium found in situ at Lothagam were in fine-grained sedi-ments, those of Ceratotherium at Kanapoi and Ekora in coarse, including conglomer-atic, ones. The expeditions that collected these and other specimens were supported by Na-tional Science Foundation Grants GP-1188 and GA-425 to Patterson. We are also indebted to the Wenner-Gren Foundation for Anthropological Research for a grant to Hooijer. The drawings are by Miss Margaret Estey, the photographs bv Drs. V. J. Maglio and R. C. Wood, and the drafting by Mr. Laszlo Meszoley. The abbreviation KNM stands for Kenya Na-tional Museum. Bull. Mus. Comp. ZooL, 144(1): 1-26, July, 1972 1
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