贵州三叠纪海生爬行动物研究进展

Study Advances on Triassic Marine Reptiles in Guizhou

贵州三叠纪海生爬行动物主要产于中三叠统安尼阶关岭组第一段、第二段及上三叠统卡尼阶下部竹杆坡组、瓦窑组等 4个层位。基本上涵盖了世界三叠纪海生爬行动物的主要类型 ,有真鳍龙类、鱼龙类、海龙类及齿龙类。初步研究表明贵州三叠纪海生爬行动物特征是 :(1)其组成虽是地方性属种 ,就大的类群 ,总的特征以及特殊类群的相对性而言 ,更接近西特提斯海域的同期爬行动物群 ;(2 )这些海生爬行动物 ,特别是瓦窑组中的一些属种 (如周氏黔鱼龙 )兼具有三叠纪和侏罗纪同类群的一些特征。 (3)其生态分为两种类型 :关岭组第一、二段的海生爬行动物类群 ,个体少 ,主要生活在近岸浅水域 ;竹杆坡组和瓦窑组的海生爬行动物类群多、个体多。

Triassic marine reptiles in Guizhou mainly emerged in four horizons from bottom to top: MemberⅠand MemberⅡof the Guanling Formation of the Anisian Stage of the Middle Triassic, the Zhuganpo formation and the Wayao formation of the lower part of the Carnian Stage of the Upper Triassic, in which MemberⅠof the Guanling formation is newly excavated with marine reptile fossils. The major genera of Triassic marine reptiles in the world have been popularly found here, there are not only new genera of Sauropterygians, Ichthyosaurs, but also Thalattosaurs and Placodonts. Primarily studies show that the characteristic of Triassic marine reptiles in southwest Guizhou concern the following points: ① Although their components derived from the local genera, there are more similarities to synchronous reptile fauna of the West Tethyan in terms of large species group, the total characteristic and the correspondence with the peculiar species; ②The marine reptiles, especial the genera of the Wayao formation like as Qianichthyosaurus Zhoui, have both characteristic of same species group of the Triassic and the Jurassic ; ③ Their ecology types can be divided into two kinds: first, the marine reptiles in MemberⅠand MemberⅡof the Guanling Formation occur as small bodies and species group and lived in the near-shore shallow water; Second, the others in the Zhuganpo formation and the Wayao formation are comparatively large in bodies and species group and dwelled in the deep water of the shallow marine.