Paraceratherium linxiaense: Fossils of New Giant Rhino Species Found in China
A new species of the giant rhinoceros genus Paraceratherium has been identified from the fossilized remains found in Gansu Province, northwestern China.
The newly-identified rhino species lived during the Oligocene epoch, around 26.5 million years ago.
Named Paraceratherium linxiaense, it belongs to Paraceratherium, a small genus of extinct hornless rhinos.
“The giant rhino has been considered as one of the largest land mammals that ever lived,” said Professor Tao Deng from the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology and colleagues.
“Its skull and legs are longer than all reported land mammals, but the metapodials (long bones of the hand and feet) are not massive in outline.”
“Its body size was suitable for open woodlands under humid or arid climatic conditions.”
“Except for some remains found in Eastern Europe, Anatolia, and Caucasus, giant rhinos lived mainly in Asia, especially in China, Mongolia, Kazakhstan, and Pakistan.”
“All forms of the giant rhino, including six genera, have been recorded from northwest to southwest China through the Middle Eocene to the Late Oligocene.”
“The genus Paraceratherium was the most widely distributed form of the giant rhino, but aside from East and Central Asia, many records from East Europe and West Asia comprise fragmentary specimens,” they added.
“Only Paraceratherium bugtiense, known from the southwestern corner of the Tibetan Plateau, has ample records and undoubtable taxa identity and is key to the origin and dispersal history of Paraceratherium.”
The fossilized remains of Paraceratherium linxiaense — a complete skull and mandible with the associated atlas, and an axis and two thoracic vertebrae of another individual — were recovered from the Jiaozigou Formation of the Linxia Basin in Gansu Province, China, located at the northeastern border of the Tibetan Plateau.
The analysis of the specimens shows that Paraceratherium linxiaense is the highly derived species of its genus.
“We found that all six members of the Paraceratherium genus are sister species to Aralotherium and form a monophyletic clade in which Paraceratherium grangeri is the most primitive, succeeded by Paraceratherium huangheense and Paraceratherium asiaticum,” the paleontologists said.
“We were able to determine that, in the Early Oligocene, Paraceratherium asiaticum dispersed westward to Kazakhstan and its descendant lineage expanded to South Asia as Paraceratherium bugtiense.”
“In the Late Oligocene, Paraceratherium returned northward, crossing the Tibetan area to produce Paraceratherium lepidium to the west in Kazakhstan and Paraceratherium linxiaense to the east in the Linxia Basin.”
“Late Oligocene tropical conditions allowed the giant rhino to return northward to Central Asia, implying that the Tibetan region was still not uplifted as a high-elevation plateau,” Professor Deng said.
“During the Oligocene, the giant rhino could obviously disperse freely from the Mongolian Plateau to South Asia along the eastern coast of the Tethys Ocean and perhaps through Tibet.”
“The topographical possibility that the giant rhino crossed the Tibetan area to reach the Indian-Pakistani subcontinent in the Oligocene can also be supported by other evidence.”
“Up to the Late Oligocene, the evolution and migration from Paraceratherium bugtiense to Paraceratherium linxiaense and Paraceratherium lepidum show that the Tibetan Plateau was not yet a barrier to the movement of the largest land mammal.”
The study was published in the June 17, 2021 edition of the journal Communications Biology.
T. Deng et al. 2021. An Oligocene giant rhino provides insights into Paraceratherium evolution. Commun Biol 4, 639; doi: 10.1038/s42003-021-02170-6