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研究发现恐龙时期或存在巨型大鸟

所属:社会热点 来源:guardian 阅读:3714 次 评论:0 条 [我要评论]  [+我要收藏]

小编摘要:白垩纪末期巨鸟化石证实,远古大鸟站立身高达3米,重达50kg,体型大小堪比鸵鸟,或大如信天翁。

导读:远古大鸟是和恐龙同时代的物种,出没在距今1亿年前的中亚。巨鸟化石由苏联-东德远征队于上世纪70年代在距咸海东面600公里左右的Shakh-Shakh(哈萨克斯坦南部沙漠)发现,是巨鸟的一对下颌碎片,超过27cm长。近日,都柏林大学古生物学家Gareth Dyke通过实验证实,大鸟是迄今所知的晚白垩时期的最大鸟类。大鸟如果不会飞,站立身高能达3米,重达50kg,如果大鸟会飞,则其身形比鸵鸟还大,翼展能有4米,大小有如信天翁。远古大鸟被命名为Samrukia nessovi,Samrukia是哈萨克神话中凤凰的叫法。

Two possible body shapes for Samrukia nessovi, with a human and 'normal-sized' Mesozoic bird for scale. Samruk was a mythical Kazakh phoenix. Photograph: John Conway

Two slender shafts of bone unearthed in the remote desert of southern Kazakhstan belong to one of the largest birds ever to stalk the Earth.

The fossilised remains form two sides of the lower jaw of a bird – at least as big as an ostrich – that lived alongside dinosaurs in central Asia 100m years ago.

The size of the bones, more than 27cm-long each, point to a bird that stood two to three metres tall, making it the largest bird known from the Late Cretaceous. Many primitive birds alive at the time were closer in size to chickens.

The lack of other remains from the creature has left palaeontologists unable to confirm whether the bird was capable of flight. If it did fly, its wingspan probably topped 4m – wider than that of a large albatross.

Details of the bird, named Samrukia nessovi, are reported in the latest issue of the Royal Society journal, Biology Letters.

The two lengths of bone were uncovered at a site called Shakh-Shakh about 372 miles (600km) east of the Aral Sea during a Soviet-East German expedition in the 1970s. The fossil was reconstructed using plaster, glue and paint, to make it look like a complete jaw, passed through the hands of a German collector, and later went on display in a Belgian museum.

Gareth Dyke, a palaeontologist at University College Dublin, dissolved the plaster and other materials used to reconstruct the fossil with solvents before analysing the bone fragments. Measurements of the remains suggest they belonged to a bird whose skull was 30cm from front to back. The creature, if flightless, almost certainly weighed more than 50kg.

"This is one of the largest birds that's ever been described of any age. We don't have much of it, but we know the lower jaw is at least as big if not bigger than the ostrich lower jaw. At the age it is, it's pretty exciting," Dyke told the Guardian.

"We have always assumed that giant size in birds was something that evolved relatively late in the history of the group, so to find a specimen so early is remarkable. This is a giant of a bird with no teeth from the Late Cretaceous."

The bird earned its forename from Samruk, the mythological Kazakh phoenix. The latter part of its name honours Lev Nessov, an eccentric Russian palaeontologist who used to take the bus or train from St Petersburg into Central Asia to embark on long hikes into the desert to hunt for fossils. He killed himself in 1995 at the age of 48 after the breakup of the Soviet Union restricted his travels.

Another large bird, named Gargantuavis, that lived in southern France 70m years ago was discovered in the late 1990s. "Samrukia adds another giant bird to the Cretaceous roster. Arguably, in fact, it increases the significance of Gargantuavis, since it shows that it wasn't a one-off," said co-author Darren Naish at Portsmouth University.

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2011-08-11 14:25 编辑:jeannn
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