Abstract: Bishanopliosaurus youngi Dong, 1980 from the Jurassic Dongyuemiao Member of the Ziliujing Formation in Chongqing Municipality, China is redescribed in detail. The holotype of B. youngi is the postcranial skeleton of a young individual, but so far the most complete plesiosaurian fossil known from the Asian Jurassic. Our restudy indicates that B. youngi can be diagnosed by the bifurcated sacral ribs combined with the compressed neural spine, narrow coracoid, and the humerus with a peculiar projection. B. youngi is a valid taxon, but its phylogenetic relationships with other plesiosaurians remain uncertain mainly because of the lack of cranial features. Previous studies on the Dongyuemiao fauna and flora indicate that the sediments are of subtropical freshwater origin. The discovery of B. youngi added further information on the freshwater invasion of plesiosaurians. Freshwater plesiosaurians so far known are very fragmentary, but their wide geographic and temporal distributions suggest that the presence of plesiosaurians in freshwater environment was not uncommon in most of their history.

摘要： 侏罗纪的蛇颈龙类化石主要发现于欧洲,在世界的其他地区则比较少见。亚洲的蛇颈龙化石, 尤其是侏罗纪的属种大多破碎而难以鉴别(Sato , 1998) 。到目前为止, Bishanopliosaurus youngi (Dong , 1980) 和Yuzhoupliosaurus chengjiangensis (Zhang , 1985) 是亚洲地区最为完整的侏罗纪蛇颈龙类化石,并且化石产自对于蛇颈龙而言比较罕见的淡水沉积,因此这些材料对于了解该类群的系统发育、历史动物地理和古生态来说非常重要。 本