中国西藏出土一块最古老的猫科动物化石
[font=Verdana, Arial, Tahoma][size=12px][b]The oldest big cat fossils ever found - from a previously unknown species "similar to a snow leopard" - have been unearthed in the Himalayas.[/b][/size][/font][font=Verdana, Arial, Tahoma][size=12px][b]喜马拉雅山地区一块最古老的猫科动物化石被发掘出土——这是一种“类似于雪豹”的未知物种。[/b][/size][/font]
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[color=#0000FF]It is rare for such an ancient carnivore fossil to be so well preserved[/color]
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[font=Verdana, Arial, Tahoma][size=12px]The skull fragments of the newly-named Panthera blytheae have been dated between 4.1 and 5.95 million years old.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]Their discovery in [url=http://www.enread.com/news/cultureandedu/94726.html]Tibet[/url] supports the theory that big cats evolved in central Asia - not Africa - and spread outward.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]The findings by US and Chinese [b]palaeontologists（古生物学家）[/b] are published in the Royal Society journal Proceedings B.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]They used both anatomical and DNA data to determine that the skulls belonged to an extinct big cat, whose territory appears to overlap many of the species we know today. [/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"This cat is a sister of living snow leopards - it has a broad forehead and a short face. But it's a little smaller - the size of clouded leopards," said lead author Dr Jack Tseng of the University of Southern California.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"This ties up a lot of questions we had on how these animals evolved and spread throughout the world.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"Biologists had hypothesised that big cats originated in Asia. But there was a division between the DNA data and the [url=http://www.enread.com/news/cultureandedu/94726.html]fossil[/url] record."[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px][b]Surprising find[/b][/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]The so-called "big cats" - the Pantherinae subfamily - includes lions, jaguars, tigers, leopards, snow leopards, and clouded leopards.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]DNA evidence suggests they diverged from their cousins the Felinae - which includes cougars, lynxes, and domestic cats - about 6.37 million years ago.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]But the earliest fossils previously found were just 3.6 million years old - tooth fragments uncovered at Laetoli in Tanzania, the famous hominin（古人类） site excavated by Mary Leakey in the 1970s.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]The new fossils were dug up on an expedition in 2010 in the remote Zanda Basin in southwestern Tibet, by a team including Dr Tseng and his wife Juan Liu - a fellow palaeontologist.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]They found over 100 bones deposited by a river eroding out of a cliff, including the crushed - but largely complete - remains of a big cat skull.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"We were very surprised to find a cat fossil in that basin," Dr Tseng told BBC News.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"Usually we find antelopes and rhinos, but this site was special. We found multiple carnivores - badgers, weasels and foxes."[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]Among the bones were seven skull fragments, belonging to at least three individual cats, including one nearly complete skull.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]The fragments were dated using magnetostratigraphy - which relies on historical reversals in the Earth's magnetic field recorded in layers of rock.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]They ranged between 4.10 and 5.95 million years old, the complete [url=http://www.enread.com/news/cultureandedu/94726.html]skull[/url] being around 4.4 million years of age.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"This is a very significant finding - it fills a very wide gap in the fossil record," said Dr Manabu Sakamoto of the University of Bristol, an expert on Pantherinae evolution.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"The discovery presents strong support for the Asian origin hypothesis for the big cats.[/size][/font]
[font=Verdana, Arial, Tahoma][size=12px]"It gives us a great insight into what early big cats may have looked like and where they may have lived."[/size][/font]
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