Largest Land Mammal that Ever Lived
Jan 30, 2020 13:16:15 GMT -5
Post by Radrook Admin on Jan 30, 2020 13:16:15 GMT -5
Largest Land Mammal that Ever Lived
Paraceratherium is an extinct genus of hornless rhinoceros, and one of the largest terrestrial mammals that has ever existed.
It lived from the early to late Oligocene epoch (34–23 million years ago); its remains have been found across Eurasia between China and the Balkans. Paraceratherium means "near the hornless beast’’.
The exact size of Paraceratherium is unknown because of the incompleteness of the fossils. Its weight is estimated to have been 15 to 20 tonnes (33,000 to 44,000 lb) at most.
The shoulder height was about 4.8 metres (15.7 feet) and the length about 7.4 metres (24.3 feet). The legs were long and pillar-like. The long neck supported a skull that was about 1.3 metres (4.3 ft) long.
It had large, tusk-like incisors and a nasal incision that suggests it had a prehensile upper lip or proboscis.
Their lifestyle may have been similar to that of modern large mammals such as the elephants and extant rhinoceroses. Because of its size, it would have had few predators and a slow rate of reproduction. The gestation period of Paraceratherium may have been lengthy and individuals may have had long life spans.
It was a browser, eating mainly leaves, soft plants, and shrubs. It lived in habitats ranging from arid deserts with a few scattered trees to subtropical forests.
The first known fossils were collected from Baluchistan (in modern-day Pakistan) in 1846 by a soldier named Vickary, but these fragments were unidentifiable at the time. The first fossils now recognised as Paraceratherium were discovered by the British geologist Guy Ellcock Pilgrim in Balochistan in 1907–1908.
In 1910, more partial fossils were discovered in Dera Bugti during an expedition by the British paleontologist Clive Forster-Cooper.
Even more fossils were discovered in 1997 in Dera Bugti, Baluchistan, Pakistan.
A Russian Academy of Sciences expedition later found fossils in the Aral Formation near the Aral Sea in Kazakhstan; it was the most complete indricothere skeleton known, but it lacked the skull.
Various remains were found in formations of the Mongolian Gobi Desert, including the legs of a specimen standing in an upright position, indicating that it had died while trapped in quicksand, as well as a very complete skull. These remains became the basis of Baluchitherium grangeri, named by Osborn in 1923.
Dzungariotherium orgosensis was described in 1973 based on fossils—mainly teeth—from Dzungaria in Xinjiang, northwest China.
The largest skulls of Paraceratherium are around 1.3 metres (4.3 ft) long, 33 to 38 centimetres (13 to 15 in) at the back of the skull, and 61 centimetres (24 in) wide across by the zygomatic arches.
Unlike most primitive rhinoceroses, the front teeth of Paraceratherium were reduced to a single pair of incisors in either jaw, which were large and conical, and have been described as tusks.
Most predators in their habitat were relatively small—about the size of a wolf—and were not a threat to Paraceratherium.
Adult individuals would be too large for most predators to attack, but the young would have been vulnerable. Bite marks on bones from the Bugti beds indicate that even adults may have been preyed on by 10-to-11-metre (33 to 36 ft)-long crocodiles, Crocodylus bugtiensis.
The simple, low-crowned teeth indicate that Paraceratherium was a browser with a diet consisting of relatively soft leaves and shrubs andits mode of foraging would have been similar to that of the high-browsing giraffe and okapi, rather than to modern rhinoceroses, whose heads are carried close to the ground.
The reasons Paraceratherium became extinct after surviving for about 11 million years are unknown, but it is unlikely that there was a single cause. Theorized reasons include climate change, low reproduction rate, and invasion by gomphothere proboscideans from Africa in the late Oligocene, and destroyed trees and turned woodland into grassland. Once their food source became scarce and their numbers dwindled.
Paraceratherium populations would have become more vulnerable to other threats. Large predators like Hyaenaelurus and Amphicyon also entered Asia from Africa during the early Miocene; these may have predated Paraceratherium calves. Other herbivores also invaded Asia during this time.