作者：程延年  吴肖春  佐藤环

摘要：根据头骨和下颌建立了海龙一新属新种——短吻贫齿龙(Miodentosaurus brevis gen. et sp. nov.)。其正型标本是采自贵州三叠纪法郎组的一具骨架(台中自然科学博物馆标本编号NMNS一004727／F003960)。虽然头后骨胳还没有修理，但是几近完好的头骨和下颌显示出许多与众不同的特征，足以确定该标本代表了一新的海龙属种。短吻贫齿龙是个体较大的海龙，其全长超过4 m，头骨背部最长约为33 cm。吻直且极短是其最显著的特征之一。其他主要特征有：前颌骨沿前背中央有一隆嵴；上颌仅前颌骨有6枚圆锥形齿，无上颌骨齿；上颌骨沿前腹侧缘有一沟槽；下颌齿骨齿都集中在前端且至多不超过6枚。依据上述这些特征很易把短吻贫齿龙与其他已知海龙相区别。短吻贫齿龙头骨顶面松果孔大且很前位，头骨腭面的锄骨和翼骨均无齿，它的颈较长(至少可以辨认出13个颈椎)。这些特征显示短吻贫齿龙可能与包括中国安顺龙属(Anshunsaurus)在内的Askeptosauroidea超科有相近的系统关系。

关键词：贵州；卡尼期；法郎组；双孔亚纲，海龙类

卷期：45卷 03期

　　A new thalattosaurian (Reptilia: Diapsida) from the Upper Triassic of Guizhou, China 

　　CHENG Yen-Nien, WU Xiao-Chun, SATO Tamaki 

Abstract  A new thalattosaurian, Miodentosaurus brevis gen. et sp. nov., is established on the basis of the fairly preserved skull and mandible of a skeleton from the Triassic Falang Formation, Guizhou Province. M. brevis is a relatively large thalattosaurian, with a total length of more than 4 m. The very short snout, with a straight profile, is the most striking of the diagnostic characters of the new taxon. Other diagnostic features include the presence of a crest along the anterodorsal midlines of the premaxillae, the edentulous maxilla, the presence of a groove-like trough along with the anterolateral margin of the maxilla on the ventral surface, the presence of six conical premaxillary teeth, and no more than six conical dentary teeth which are restricted to the anterior portion of the dentary. The absence of the vomer and pterygoid teeth, the anterior shift of the large pineal foramen, and the elongation of the neck indicate that M. brevis may have had a close relationship with the Askeptosauroidea, to which the Chinese genus, Anshunsaurus is referred. 

Key words  Guizhou; Carnian; Falang Formation; Diapsida, thalattosaurians