Abstract: A new thalattosaur, Concavispina biseridens gen. et sp. nov., is established on the basis of a new skeleton from Xiaowa Formation of Guangling, Guizhou, China. It is diagnosed by two rows of blunt teeth on anterior part of maxilla and V-shaped notch on the dorsal margin of neural spines in dorsal vertebrae. It shares three derived characters only with Xinpusaurus: anterior end of maxilla curved dorsally; cervical vertebrae less than five; proximal end of humerus wider than distal end. This indicates that the new taxon may have a closely relationship withXinpusaurus.

摘要： 简要记述了产自贵州关岭小凹组的一具基本完整的骨架，在此基础上建立了海龙类的一个新属种，双列齿凹棘龙(Concavispina biseridens)。新种最明显的鉴定特征是：上颌骨前端有两列钝的牙齿，后部无齿；背椎神经棘背缘形成V形缺口。凹棘龙与新铺龙(Xinpusaurus)独有的衍征包括上颌骨前段背向弯曲，颈椎数目小于5枚，肱骨近端比远端宽。这些特征指示凹棘龙与新铺龙可能具有较近的亲缘关系。