A new late Miocene elasmotheriine rhinoceros from Morocco

摘要

We describe here the first definite representative of the subfamily Elasmotheriinae in North Africa. It comes from the upper Miocene site of Skoura near Ouarzazate, on the southern slope of the Central High Atlas in Morocco. It consists of a virtually complete skull with articulated mandible and a few fragmentary postcranial remains, making it by far the best known elasmotheriine from the African late Miocene. We assign it to a new taxon, Eoazara xerrii gen. et sp. nov. The skull is characterized by long nasal bones indicating a strong horn and long, anteriorly expanded, edentulous pre-maxillae. Compared to other Rhinocerotidae, the face is moderately elongated; the lower incisors are of medium size; and the premolar row is short. The upper molars have a strongly pinched protocone, a long antecrochet, and an unexpanded central valley. Eoazara xerrii gen. et sp. nov. is at a lower evolutionary grade than the Chinese species of Ningxiatherium and Parelasmotherium, but probably comparable to the very incomplete remains from the East African late Miocene forms. We regard Eoazara as a member of a chiefly Eurasian clade, rather than as a survivor of a hypothetical African elasmotheriine branch. Parsimony analysis confirms the monophyly of the Elasmotheriinae, but that of the remaining Rhinocerotidae is questionable.