Rusingoryx atopocranion is a poorly known extinct alcelaphine bovid, documented in Pleistocene deposits associated with Middle Stone Age artifacts on Rusinga Island, Kenya. Following its initial description, Rusingoryx was subsumed into Megalotragus, which includes the extinct giant wildebeests, on the basis of its cranial architecture. Renewed investigations of the Pleistocene deposits on Rusinga Island recovered a large sample of Rusingoryx specimens that provide new taxonomic and paleoecological insight. This study (1) reviews the morphological and phylogenetic evidence concerning the taxonomic status of Rusingoryx and (2) evaluates its paleoecology and dietary habits. The morphology and phylogenetic data indicate that Rusingoryx is distinct from Megalotragus; they likely shared a common ancestor in the late Pliocene. Ecomorphology and mesowear analysis point to a specialized grazing adaptation, and its association with arid-adapted ungulates suggests a preference for arid grasslands. The confirmation of Rusingoryx as a valid taxonomic entity, together with the presence of other extinct taxa (including Megalotragus) on Rusinga Island, suggests an increasingly complex pattern of ungulate biogeography and extinctions in the late Quaternary of East Africa. Rusingoryx appears to have been part of an arid-adapted faunal community that potentially persisted in East Africa until the onset of the Holocene.
Bibliographical noteFunding Information:
The research reported here was conducted under research permit NCST/5/002/R/576 issued to C.A.T by the Republic of Kenya as well as an exploration and excavation license issued by the National Museums of Kenya (NMK). Our field and laboratory work is made possible through the support of the NMK (particularly Drs. Emma Mbua, Frederick Kyalo Manthi, Isaya Onjala, and Ms. Julian Ogondo) and the British Institute in East Africa, with funding provided by the National Science Foundation ( BCS-1013199 , BCS-1013108 ), the Leakey Foundation , and the National Geographic Society's Committee for Research and Exploration (grant # 8762-10 ). J.T.F. thanks Bernard Wood for emphasizing the importance of systematics, and J.N.C. thanks the Willi Hennig Society for providing free access to their software. We thank the two anonymous reviewers and Alan Gillespie (editor) for their constructive comments on a previous version of this manuscript.
- Lake Victoria
- Phylogenetic systematics
- Quaternary extinctions