A new elasmothere genus and species from the middle Miocene of Tongxin, Ningxia, China, and its phylogenetic relationship

Abstract

The elasmotheres were well diversified and widespread throughout the Neogene in Eurasia and East Africa. Here we report a new elasmothere genus and species, Tongxinotherium latirhinum gen. et sp. nov., from the Zhang’enbao Formation (middle Miocene) of Tongxin, Ningxia, China. The new genus is characterized by a broad and thick nasal bone, the ‘U’-shaped nasal notch located at the level of P3, the anterior margin of the orbit situated at the level of M2, subhypsodont teeth covered and filled by plentiful cement, slightly developed enamel foldings, expanded protocone with anterior and posterior constrictions, the middle valley and posterior valley closed on the premolars, protoloph separated from the ectoloph on P2, and buccal and lingual cingula present on premolars, but absent on molars. A phylogenetic analysis reveals that Tongxinotherium latirhinum gen. et sp. nov. is more derived than the early elasmotheres, and more primitive than Iranotherium and Ningxiatherium, bridging a morphological and stratigraphical gap between them. The discovery of new material improves the morphological characteristics of the early elasmotheres’ horns and increases the diversity of the middle Miocene elasmotheres. http://zoobank.org/urn:lsid:zoobank.org:pub:7DF2F57F-38DD-4FBF-B3DF-57AADD510131