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Several rhinocerotid cheek teeth and mandibular fragments from the upper Miocene of the Samburu Hills and Nakali in northern Kenya are described. These specimens show characteristics that place them in the Tribe Elasmotheriini such as a constricted protocone, a developed antecrochet, and coronal cement. The present specimens are compared with other Elasmotheriini species from Eurasia and sub-Saharan East Africa. They are found to be morphologically different from the previously known species of Elasmotheriini. Morphologically, they are most similar to Victoriaceros kenyensis from the middle Miocene of Kenya, but differ from V. kenyensis in having the upper molars with the simple crochet, lingual groove of the protocone and enamel ring in the medisinus. Therefore, the present specimens are assigned to a new genus and species of Elasmotheriini: Samburuceros ishidai. A cladistic analysis tentatively places S. ishidai nov. gen., nov. sp. as a sister taxon of V. kenyensis. However, questions remain regarding a further detailed discussion of the phylogenetic relationship between the African Elasmotheriini and other Eurasian taxa because of the incompleteness of the specimens from Africa, as already noticed by several researchers.

We describe new material of Rhinocerotidae recently collected in western Kenya. A skull from Karungu is one of the best-preserved Miocene skulls in Africa. It differs substantially from that of Rusingaceros leakeyi, the only other relatively well-known rhino from this region and age, in its degree of brachycephaly, possession of a deep nasal notch, and long nasal bones that probably carried a horn of moderate size. Miocene African rhinos are still too poorly known to resolve their phylogenetic relationships, but we tentatively assign this skull to a new species of Victoriaceros, a genus whose type species comes from the younger site of Maboko, although the Karungu skull has a much smaller nasal horn. A parsimony analysis resolves them as sister species within the Elasmotheriini, close to the other African genera Turkanatherium and Chilotheridium, but we consider this result debatable, as Victoriaceros differs considerably from them. Still, they might all be descended from European forms. A partial...

The middle Miocene site of Maboko (Lake Victoria, Kenya), dated to ca. 15 Ma, has yielded one of the best collection of rhinos in Africa. The most common taxon, Victoriaceros kenyensis n.gen., n.sp., is represented by an almost perfect skull (whose main features are the large nasal horn, an orbit located very anteriorly and with a prominent border, and very broad zygomatic arches) and numerous limb bones, probably belonging to only a few individuals. Characters of the teeth and skull support an assignment to the subfamily Elasmotheriinae, a group best known in the middle and upper Miocene, but whose monophyly is disputable, as some of their tooth characters could be adaptations to a grazing diet (in agreement with their distribution in the Maboko beds). In any case, Victoriaceros clearly differs from other East African middle Miocene rhinos, whose diversity is far greater than currently assumed. A few other specimens attest to the occurrence at Maboko of at least one other species, perhaps close to the brachypotheres; a single calcaneum is tentatively assigned to the Chalicotheriidae.