贵州关岭生物群盘江鱼龙体内胃融物研究

Gut contents in the Triassic ichthyosaur Panjiangsaurus from the Guanling biota in Guizhou

本文主要描述了关岭生物群中一美丽盘江鱼龙标本(YIGM V30016)-Panjiansaurus epicharis Chen & Cheng体内的胃融物。其组成物质为微晶含有机质胶磷质生物碎屑灰岩。其中生物碎屑主要为较小的鱼类骨碎片,其次含有少量的双壳类外壳,没有胃石。通过分析胃融物的成分,比较牙齿类型和身体特征等,认为盘江鱼龙主要以小型鱼类和双壳类为食,并不需胃石帮助消化食物。

Ichthyosaurs were one of highly successful groups adapted to the aquatic environment in the Mesozoic marine reptiles. However, only a few gut contents have been reported so far despite the fact that a number of articulated skeletons are known from this clade. Recently weU-preserved ichthyosaur specimens have been found in the Guanling biota in the Lower Member of the Upper Triassic Xiaowa Formation in Guizhou, Southwest China. Among them, one specimen of Panjiangsaurus epicharis CYIGM V30016） with gut content is studied for exploiting the dietary habits of this taxon. The gut content is micrite with organic phosphatic biodetritus. The biodetritus is mainly composed of many small fish bone fragments with small quantity of bivalve shells. No gastroliths were found inside the gut contents. Panfiangsaurus, which had a long body and long tail and lacked blunt teeth, was probably an ambush predator, whereas post-Triassic ichthyosaurs were high-speed pursuit predators. It is indicated that Panjiangsaurus possibly fed on small fishes and bivalves, and that it did not need gastroliths for food trituration.