New fossils reveal one of the largest land mammals ever found – and it’s a giant rhinoceros
About 25 million years ago, giant rhinos roamed the earth with a height of more than 5 meters. They are believed to be the largest land mammal that ever lived – but their evolutionary history and spread across Asia have puzzled scientists.
Paleontologists have now found fossils for a new, sixth species of the extinct giant rhinoceros, Paraceratherium linxiaense, that shed light on how the animal moved through China, Mongolia, Kazakhstan and Pakistan. The research team, led by Deng Tao of the Institute of Vertebrate Paleontology and Paleoanthropology, published its 2015 results in a new study this week in the journal Communications Biology.
The researchers discovered a fossil of a fully preserved skull, jawbone, and teeth with the associated atlas, the part of the body where the head is connected to the spine. Another fossil consists of three vertebrae.
The remains provided enough detail for the team to create a 3D digital model and compare it to other giant rhinos – which led to the classification of the new species, which is characterized by its longer, more flexible neck.
The rare fossils found in Gansu Province, China, on the northeastern edge of the Tibetan Plateau, date from the late Oligocene, an era that lasted about 34 million years ago to about 23 million years ago.
These giant rhinos were significantly larger than today’s rhinos, with an estimated shoulder height of around 5 meters and weighing over 40,000 pounds. They also lacked horns.
The discovery sheds light on how the region has changed since these giant creatures became extinct.
“The Tibetan region likely hosted some low elevation areas, possibly less than 2,000 meters during the Oligocene, and the ancestry of the giant rhinos may have spread freely along the east coast of the Tethys Ocean and perhaps through some of the lowlands of that region,” the researchers wrote in the study.
The researchers found that the animal spread westward to Kazakhstan in the early Oligocene, returned to South Asia with an offspring, and then returned north to cross Tibetan territory to eventually produce P. linxiaense to the east in the Linxia Basin .
“The tropical conditions of the late Oligocene allowed the giant rhinoceros to return northward to Central Asia, suggesting that the Tibetan region has still not been raised as a high plateau,” Deng said.