海龙类化石在云南泸西上三叠统的发现

The discovery of Thalattosauria(Reptilia:Diapsida) from the Late Triassic strata of Luxi County, Yunnan Province

采自云南泸西县城附近小兴安村晚三叠世卡尼期小凹组的海龙化石,是关岭生物群海龙类化石在贵州关岭之外地区的首次发现。该化石标本共保存有9枚较好的背椎骨,21条完好的肋骨及若干腹肋。靠近头部的4枚背椎骨为有次序的自然排列。背椎椎体长约12cm,椎体横突发育,椎体腹侧轻微凹入,呈双凹形,近似圆形。这一特征与鱼龙类脊椎骨明显的双凹特征有所区别,故暂且将其归于海龙类。新采集的该化石标本为探讨海龙类的古地理分布,以及寻找规律生物群新化石产地提供了信息。

This paper reposts a thalattosaur specimen collected from the Late Triassic Xiaowa Formation in Xiaoxingan Village, Luxi County, Yunnan Province. It is the first record of Thalattosauria fossil outside Guanling, Guizhou Province. The specimen consists of 9 well preserved dorsal vertebrae, 21 dorsal ribs, and several gastralia. 4 dorsal vertebrae are present and arranged as a sequence of natural order. The length of dorsal vertebrae is about 12 cm. The transverse process is well developed. The two ends of the dorsal vertebrae are slightly biconcave, distinctly different from ichthyosauria vertebrae with obvious biconcave. The specimen is tentatively assigned to the Thalattosauria. The new discovery provides new information for paleobiographic distribution of the Thalattosauria and the search for new fossil localities of the Guangling biota.