近日，美国犹他州境内发现一种恐龙新物种，它具有强壮的腿部肌肉。科学家认为这种恐龙利用强壮的腿部肌肉可以踢赶同类或者抵御掠食者。
据国外媒体报道，这种新恐龙的学名为“Brontomerus mcintoshi”，或被称为“雷腿龙”，是由一支美国和英国科学家小组发现的。雷腿龙是一种属于蜥脚类恐龙的长颈恐龙，该物种还包括梁龙和腕龙，它们 生活在1.1亿年前的白垩纪早期。很可能它们与恐爪龙、猛禽龙等恐龙发生过激烈战斗。
研究人员在犹他州东部一处采石场发现两具雷腿龙骨骼化石，分别是成年体和幼年体。古生物学家猜测较大体形的成年体是幼年体恐龙的母亲，成年体恐 龙重量大约6吨，相当于体形较大的大象，体长达14米，腿部长2米。幼年体恐龙仅是成年体的三分之一，估计其质量仅有200公斤，体形相当于矮种马，体长 约4.5米。目前，这项最新研究发表在《波兰古生物学报》期刊上。
科学家表示，雷腿龙是蜥脚类恐龙家族中拥有最强壮腿部肌肉的成员。伦敦大学学院地球科学系研究员泰勒(Mike Taylor)说:“雷腿龙是一种十分吸引人的恐龙，这对于我们是一项令人兴奋激动的考古发现。当我们发现它外形奇特的臀部骨骼时，便意识到这将是具有重大意义的一项研究，最终研究证实它们可能是‘踢腿高手’，以此抵御掠食者，或者出现在两只雄性在争斗异性配偶时发生的战斗。”（生物谷Bioon.com）
生物谷推荐原文出处：
Acta Palaeontologica Polonica 56 (1), 2011: 75-98 doi:10.4202/app.2010.0073
A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA
Michael P. Taylor, Mathew J. Wedel, and Richard L. Cifelli
Brontomerus mcintoshi is a new genus and species of sauropod dinosaur from the Hotel Mesa Quarry in Grand County, Utah, USA, in the upper part of the Ruby Ranch Member (Aptian–Albian) of the Lower Cretaceous Cedar Mountain Formation. It is known from at least two fragmentary specimens of different sizes. The type specimen is OMNH 66430, the left ilium of a juvenile individual; tentatively referred specimens include a crushed presacral centrum, a complete and well?preserved mid?to?posterior caudal vertebra, the partial centrum of a distal caudal vertebra, a complete pneumatic anterior dorsal rib from the right side, the nearly complete left scapula of a much larger, presumably adult, individual, and two partial sternal plates. Brontomerus is diagnosed by five autapomorphies of the type specimen: preacetabular lobe 55% of total ilium length, longer than in any other sauropod; preacetabular lobe directed anterolaterally at 30o to the sagittal, but straight in dorsal view and vertically oriented; postacetabular lobe reduced to near absence; ischiadic peduncle reduced to very low bulge; ilium proportionally taller than in any other sauropod, 52% as high as long. In a phylogenetic analysis, Brontomerus was recovered as a camarasauromorph in all most parsimonious trees, but with uncertain position within that clade. The large preacetabular lobe of the ilium anchored powerful protractor and abductor muscles, but precise interpretation is impossible without functionally related elements such as femora and proximal caudal vertebrae. Brontomerus is the eighth sauropod genus named from the Early Cretaceous of North America, and more remain to be described: North American sauropod diversity did not decline catastrophically at the end of the Jurassic as often assumed. The most striking differences between Late Jurassic and Early Cretaceous sauropod faunas in North America is that the former are abundant and dominated by diplodocids, whereas the latter are comparatively scarce—though still diverse—and dominated by macronarians.
Key words: Dinosauria, Sauropoda, Camarasauromorpha, Brontomerus, Brontomerus mcintoshi, diversity, Early Cretaceous, North America.
