海龙的起源和演化

The origin and evolution of thalattosaurs

海龙是三叠纪起源不明的一类海生爬行动物,与鳍龙和鱼龙共同构成了当时海洋生态系统的三大主要捕食者类群。海龙的研究对从高级捕食者的角度理解二叠–三叠生物大绝灭之后生态系统的复苏重建具有重要意义。海龙的研究已有100余年的历史,近些年来由于分支系统学等新方法的应用而得到了新的认识。本文从海龙的起源,物种多样性,谱系发育重建,生物地理分布四个方面概述了学界的研究进展。在目前的研究基础上指出,在时代更早的地层中进行更深入的野外工作,对华南海龙属种的系统厘定,以及海龙骨组织学研究的开展,是未来海龙研究的主要方向。

Thalattosaurs are one of the three major groups of top reptilian predators in the Triassic marine ecosystems, the study of which is a key to our understanding of biotic recovery from the Permo-Triassic mass extinction. Significant advancement has been achieved in the last decades in studying biodiversity and phylogeny of thalattosaurs. However, the origin of thalattosaurs and the process forming the biogeographical pattern of thalattosaurs largely remains an enigma. We review here the recent progress in the study of thalattosaurs in terms of its origin, species diversity, phylogeny and biogeography. Our review shows that large gap exists in the research of thalattosaurs. Future research should be focused on field work in the early part of the Triassic strata to search for more primitive thalattosaurs. This is necessary to elucidate its origin. A first-hand systematic review of thalattosaurs from SW China should be performed to clarify the true biodiversity of thalattosaurs, which is also a basis for a comprehensive phylogenetic analysis of thalattosaurian relationships. Finally, the study of the physiology and paleoecology of thalattosaurs via the investigation of long bone histology and microanatomy is of great significance in establishing the process forming the biogeographical pattern of thalattosaurs.