记云南晋宁发现的双嵴龙(Dilophosaurus)化石

A NEW THEROPODA (DILOPHOSAURUS SINENSIS SP. NOV.) FROM YUNNAN, CHINA

1987年8月,在晋宁县夕阳彝族乡木杵榔村的青龙山采到两具恐龙,一为近于完整的兽脚类的双嵴龙,另一具为原蜥脚类的云南龙(Yunnanosaurus)。它们出自早侏罗世下禄丰组。鉴于晋宁木杵榔发现的双嵴龙在中国乃至亚洲尚属首次记录,特此简报。

In 1987, a team from the Knnming Muni ipal Museum found and excavated a nearly complete specimen of a new species of theropod, Dilophosaurus sinensis, from Xiyang Village, Jinning County, Yunnan Province. The sp cimen was associated with a skeleton of Yunnanosaurus in the Lower Jurassic sediments of the Lower Lufeng Formation. The discovery of Dilophosaurus in China suggests there were close connections between North America and Asia during the Early Jurassic.Diagnosis The most characteristic fetures of the Yunnan specimen are a pair of bony crests on the skull, and a deep notch sep rating the dentigerous margins of the premaxilla and maxilla. The skull is large in proporion to its 5.5 metre long body. These features are shared with Dilophosaurus wetherilli from the Kayenta Formation of Arizona, North America. The Chinese specimen is distinctive in that the bony crests are higher and thicker, and converge posteriorly to contact on the mid ine, the snout is rather short; the teeth of the upper and lower jaws are shorter and stronger; nd there are 5 premaxillary, 13 maxillary and 13 dentary teeth, compared with a dental formula of 4/12/17 in D. wetherilli. One antorbital fenestra is present in the maxilla, although a se ond is represented by a foramen.