Brusatte Stephen L, Benson Roger B J, Chure Daniel J, Xu Xing, Sullivan Corwin, Hone David W E
Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA.
Naturwissenschaften. 2009 Sep;96(9):1051-8. doi: 10.1007/s00114-009-0565-2. Epub 2009 Jun 2.
Little is known about the evolution of large-bodied theropod dinosaurs during the Early to mid Cretaceous in Asia. Prior to this time, Asia was home to an endemic fauna of basal tetanurans, whereas terminal Cretaceous ecosystems were dominated by tyrannosaurids, but the intervening 60 million years left a sparse fossil record. Here, we redescribe the enigmatic large-bodied Chilantaisaurus maortuensis from the Turonian of Inner Mongolia, China. We refer this species to a new genus, Shaochilong, and analyze its systematic affinities. Although Shaochilong has previously been allied with several disparate theropod groups (Megalosauridae, Allosauridae, Tyrannosauroidea, Maniraptora), we find strong support for a derived carcharodontosaurid placement. As such, Shaochilong is the first unequivocal Asian member of Carcharodontosauridae, which was once thought to be restricted to Gondwana. The discovery of an Asian carcharodontosaurid indicates that this clade was cosmopolitan in the Early to mid Cretaceous and that Asian large-bodied theropod faunas were no longer endemic at this time. It may also suggest that the ascent of tyrannosaurids into the large-bodied dinosaurian predator niche was a late event that occurred towards the end of the Cretaceous, between the Turonian and the Campanian.
关于亚洲早白垩世至中白垩世大型兽脚亚目恐龙的演化，我们所知甚少。在此之前，亚洲是基础坚尾龙类特有动物群的家园，而白垩纪末期的生态系统则由暴龙科主导，但其间的6000万年留下的化石记录稀少。在这里，我们重新描述了来自中国内蒙古土伦阶的神秘大型毛儿图吉兰泰龙。我们将这个物种归入一个新属——韶颌龙，并分析它的系统亲缘关系。尽管韶颌龙此前曾与几个不同的兽脚亚目类群（斑龙科、异特龙科、暴龙超科、手盗龙类）有联系，但我们发现它强烈支持归入进步的鲨齿龙科。因此，韶颌龙是鲨齿龙科第一个明确无误的亚洲成员，鲨齿龙科曾一度被认为仅限于冈瓦纳大陆。亚洲鲨齿龙科的发现表明，这个类群在早白垩世至中白垩世是世界性分布的，而且此时亚洲大型兽脚亚目动物群不再是特有的了。这也可能表明，暴龙科在大型恐龙捕食者生态位上的崛起是一个较晚的事件，发生在白垩纪末期，即土伦阶和坎帕阶之间。
