Extinct elephant 'survived late' in North China
Palaeoloxodon was believed to have died out around 10,000 years ago
Wild elephants living in North China 3,000 years ago belonged to the extinct genus Palaeoloxodon, scientists say.
They had previously been identified as Elephas maximus, the Asian elephant that still inhabits southern China.The findings suggest that Palaeoloxodon survived a further 7,000 years than was thought.
The team from China examined fossilised elephant teeth and ancient elephant-shaped bronzes for the study.
The research, published in Quaternary International was carried out by a group of scientists from Shaanxi Normal University and Northwest University in Xi'an and The Institute of Geographic Sciences and Natural Resources Research, Beijing.
Continue reading the main story
Meet the armadillo's gigantic relative
See how sabre-tooth tigers killed
How did mammoths adapt to extreme cold?
Beasts of the Pleistocene
See how sabre-tooth tigers killed
How did mammoths adapt to extreme cold?
No wild elephants live in North China today, but historical documents indicate that they roamed freely 3,000 years ago.
For decades experts believed that the ancient elephants were E. maximus - a species adapted to a tropical climate and that is still found in China's southerly Yunnan province."They thought North China was controlled by tropical climate at that time," explained Ji Li, from Shaanxi Normal University, who collaborated on the study with colleagues professor Yongjian Hou, professor Yongxiang Li and Jie Zhang.
But later research into China's climate history indicates that 3,000 years ago most parts of North China were still controlled by the warm temperate climate zone, and not the subtropic zone.
This discovery would mean that "the air temperature of North China 3,000 years ago was still not high enough for Elephas to live," said Mr Li.
"The species of the elephants is not only a problem of zoology, but also a problem about global climate change," he added.
Palaeoloxodon was thought to have disappeared from its last stronghold in China just before the Pleistocene-Holocene boundary, around 10,000 years ago.
To investigate whether these mammals continued to live beyond the Pleistocene epoch and into the Holocene (the current geological epoch), the team re-examined fossilised elephant teeth discovered in Holocene layers of rock in North China during the 1900s.
Palaeoloxodon's thick tusks reached 3-4m in length
"The tusks of Palaeoloxodon are thicker, stronger and longer than [those of] E. maximus", he explained, whereas E. maximus's tusks are "more incurvate".
Ancient treasures The team also examined dozens of ancient elephant-shaped bronze wares from the Xia, Shang and Zhou dynasties (around 4,100-2,300 years ago) after Mr Li noticed the trunks on the ornaments didn't resemble those of E. maximus.
Elephants can either have one or two of "fingers" on the tip of their trunk, used for grasping objects.
The 33 elephant bronzes exhumed from different sites in North China all depicted elephants with two "fingers" on their trunks, while E. maximus (Asian elephant) has just one "finger".
Whether Palaeoloxodon had one or two fingers on its trunk is not known. "However, on the trunk of E. maximus, there cannot be two fingers," writes Mr Li in the study.
The age of these elephant-shaped bronzes supports the researchers' theory that Palaeoloxodon did not become extinct until thousands of years later than thought.
Their findings correlate with other recent paleontological discoveries that further large mammal species, thought to have died out at the end of the Pleistocene, actually lasted in to the Holocene.
These include the woolly rhinoceros (Coelodonta antiquitatis), woolly mammoth (Mammuthus primigenius) and the aurochs (Bos primigenius).
Such discoveries suggest that the extinction period of many Pleistocene land mammals may have lasted longer than was previously thought.
Join BBC Nature on Facebook and Twitter @BBCNature.
ไม่มีความคิดเห็น:
แสดงความคิดเห็น