Elasmosaurids are a cosmopolitan group of plesiosaurians that radiated during the Late Cretaceous. A new specimen of the small sized elasmosaurid Kawanectes lafquenianum is described here. New features of the basicranium and palate are added: basioccipital tubers with distal end deeply excavated, basioccipital ventral flat plate below occipital condyle, absence of posterior interpterygoid symphysis, parasphenoid extended caudally to the posterior margin of basioccipital condyle, craniocaudally short ventral keel of parasphenoid. Differences recorded between the specimens referred to K. lafquenianum (ilium shape, relative humerus to femur size and sacral centrum proportions) are described. Different explanations of these differences are discussed, concluding that sexual dimorphism is the most plausible explanation.

Elasmosaurids是一群在白垩纪晚期辐射的蛇颈龙。此处描述了一种新的小型弹力龙虾Kawanectes lafquenianum的标本。增加了碱性ran和pa的新功能：远端挖出的基底枕形块茎，枕骨below下方的基底枕腹侧平板，不存在后蝶骨共突，蝶骨向尾延伸至基底枕骨con突的后缘，颅骨蝶骨短腹侧龙骨。记录在试样之间的差异称为ķ。紫花苜蓿（八字形，相对于股骨的肱骨相对大小和骨中心比例）进行了描述。讨论了对这些差异的不同解释，认为性二态性是最合理的解释。