三叠纪鳍龙类的地层分布及其演化

THE STRATIGRAPHIC DISTRIBUTION,MIGRATION AND PHYLOGENY OF THE TRIASSIC SAUROPTERYGIANS

三叠纪的鳍龙类主要在近岸浅水环境中生活,多数分布在特提斯洋区,而在北美地区极少且仅发现两属。近年来我国华南地区发现的多层位保存的三叠纪鳍龙类材料为探讨鳍龙类的起源、迁移与演化提供了新的信息,同时也向传统的认识提出了挑战。目前三叠纪鳍龙类的地层发生序列与演化谱系之间仍然存在矛盾,基于系统演化研究得出的西特提斯区起源说与我国近年来在安徽巢湖的新发现不完全一致。这主要是由于其地层产出序列以及化石保存不完整所致,未来有待于在我国以及世界其他更古老地层中化石材料的发现,以及基于所有标本对三叠纪鳍龙的谱系演化的系统认识。

Triassic sauropterygians mainly lived in nearshore shallow water. They have a wide distribution along the east and west Tethys while they were hardly found from the North America （only two genera so far）. During the past fifteen years, many new materials of the Triassic sauropterygians were found from multiple stratigraphic horizons of the Triassic of South China, supplementing and also challenging our tra- ditional knowledge of this group. So far a remarkable contradiction is still present between the stratigraph- ic occurrences and phylogeny in the Triassic sauropterygians and our recent discovery from Chaohu, Anhui Province does not supported a Western Tethys origin of the group as suggested by previous research. This is possibly resulted from the incompleteness of specimens and more new materials are expected from even older strata of South China and other localities. A comprehensive revision of all the taxa based on the new materials will provide us new understanding of the phylogeny of Triassic sauropterygians.