贵州关岭晚三叠世一大型鱼龙类头骨

CYMBOSPONDYLUS FROM THE UPPER TRIASSIC OF GUIZHOU, CHINA

记述了产自贵州关岭上三叠统杯椎鱼龙属一新种——亚洲杯椎鱼龙(Cymbospondylusasiaticus sp. nov)。标本为两件几乎完整的头骨,产于法朗组瓦窑段的泥质灰岩中,这是目前已知惟一的晚三叠世(Cymbospondylus属的标本,也是该属时代最晚的一个种。亚洲杯椎鱼龙头部最明显的特征是下颌牙齿仅分布于齿骨的前半部分。此外,新种的吻部极长,超过头骨全长之半,上颌骨非常发达,并且具有已知鱼龙类中最小的眼眶。亚洲杯椎鱼龙是这一大型鱼龙类在北美和欧洲以外地区的首次记录。

A new species of Cymbospondylus is named and described on the basis of twowell-preserved skulls from the Late Triassic Wayao Member of the Falang Formation at Guanling, Guizhou Province. The prominent character of the new species is the teeth on the lower jaw, which only exist on anterior half of the dentary . Furthermore, it has large maxilla and relatively, has the smallest orbit in the known ichthyosaurs. This is the latest occurrence of the genus Cymbospondylus , which is previously known only from the Middle Triassic of North America and Europe.