Paleontologists have discovered fossils of a previously unknown species of cursorial hyena that lived in what is now Tibetan Plateau during the middle Pliocene, 4.9-4.1 million years ago.

Life reconstruction of a pair of Chasmaporthetes gangsriensis. Image credit: Julie Selan.

Cursorial hyenas (Chasmaporthetes), also known as hunting or running hyenas, are an extinct genus of hyenas endemic to North America, Africa, and Asia during Pliocene and Pleistocene periods.

The oldest representatives of Chasmaporthetes appeared in the late Miocene of Greece, Chad, and China. However, the genus was already widespread at the time of their earliest record around 7 million years ago.

By the early Pliocene, Chasmaporthetes crossed the Bering land bridge to America, where they evolved into Chasmaporthetes ossifragus, becoming North America’s only native hyena before being brought to extinction by the end of the Ice Age.

The new fossils of Chasmaporthetes, including partial lower jaws, maxillae, and toe bones, were collected from the Pliocene deposits of the Zanda Basin in southwestern Tibetan Plateau in 2009, and identified as a new species, Chasmaporthetes gangsriensis.

“Chasmaporthetes gangsriensis is morphologically the most basal Pliocene Chasmaporthetes in China, and is consistent with the ‘out of Tibet’ hypothesis for some Pleistocene megafauna”, said Dr Zhijie Jack Tseng of Natural History Museum of Los Angeles County and University of Southern California, who is the lead author of a paper published in the Journal of Vertebrate Paleontology.

Partial left maxilla of Chasmaporthetes gangsriensis. Scale bar – 20 mm. Image credit: Tseng ZJ et al.

Chasmaporthetes gangsriensis is the smaller among Plio-Pleistocene Eurasian species of the genus.

“The discovery of this cursorial hyaenid species provides additional evidence for open environments in the western Himalayan foothills no later than the Pliocene, as consistent with previous evidence from Zanda Basin’s fossil horses and herbivore enamel isotope analyses,” said study co-author Dr Qiang Li from the Institute of Vertebrate Paleontology and Paleoanthropology.

Dr Li added: “recent field work in the Zanda Basin in southwestern Tibetan Plateau has provided new fossil evidence of vertebrate faunas spanning the late Miocene to Pleistocene, which represents new occurrences hitherto unknown in that region of Asia and allows the establishment of a faunal sequence in the basin for the first time.”

Source: sci.news