【摘要】 <正> 我国自一九六○年以来,陆续在贵州织金下三叠统、广东开恩下侏罗统、福建华安上二叠统以及陕西麟游下三叠统均采获有蛇尾化石,使我国的蛇尾化石纪录逐渐丰富.近又于我国西部边陲获新的资料.一九八○年武汉地质学院西藏科考队与西藏地质局第二地质大队科考分队共同组成地质部高原地调大队四分队,在阿里地区日土县多玛区热维尔西北支沟中,采得较完好的蛇尾化石标本.化石产在褐黄色含生物碎屑的泥灰岩中,同一块标本上有三个蛇更多还原

【Abstract】 Among collections brought back from Rutog of the Ngari area, Xizang is a marlstone slab with three fairly well-preserved speciments of ophiuroids, which serve as types for two new taxa—Ophiaulaxoides alicnsis and O. yaraliensis. They are considered to be of Middle Jurassic age, for they occur immediately below the beds yielding Holcothyris angulata Buckman(Brachiopod), which marks the Bathonian of Burma. Ophiaulaxoides(gen. nov. ) Disc with thickened margin only, showing no radial shields. No granulose skin is preserved, though in life it should be present as a dorsal cover for the disc. Oral opening relatively small, being about haIf the width of the disc. Laterals wrapped around arms; dorsal and ventral arm-plates (shields) small and rhombic. Short spines on laterals. Five or more arm-plates lying within the oral surface of the disc. Vertebrae small, rectangular. This new genus resembles Ophiaulax Ubaghs 1941 in having well-developed, thickened margin only, but differs from the latter in the distinctly stellate oral opening surrounded by buecal shields (orals, arm-plates and jaws). It is distinguished from Ophiurina Sturtz 1890 by having dorsal and ventral armplates Type species: Ophiaulaxoides aliensis (gen. et sp. nov. ) Ophiaulaxoides aliensis (gen. et sp. nov￡(r)) Disc rolatively large with fairly large margin; stellate oral opening surrounded by first pair of arm-plates and half jaw-plates—hal jaw-plates of two adjacent arms being in contact; arrn slender and simple with small disconnected dorsal plates, well-developed laterals Which connect with each other both dorsally and ventrally by pairs, thus scparating the dorsal arm-plates. Ophiaulaxoides paraliensis(gen. et sp. nov. ) Disc relatively large; stellate oral opening surrounded by arm-plates and half jaw-plateshalf jawplates of two adjacent arms being separated; arm with small disconnected dorsal and ventral arm-plates, and well-developed laterals which meet by pairs ventrally; spines simpie and short.更多还原