摘要
在贵州兴义顶效绿荫村西大约 15 0m绿荫水泥厂南面采石场出露的中三叠统杨柳井组(拉丁阶 )灰黑色中薄层灰岩中发现一新的海生爬行动物———绿荫顶效龙Dingxiaosaurusluyinensisgen .etsp .nov .。它的肢骨形态和结构颇为独特 ,股骨、胫、腓骨以及跗骨的形状和结构相似于原始的鱼龙 ,而趾骨形状和数目有些相似于最早的蛇颈龙 ,但又与所有已知的鱼龙和蛇颈龙类的属种均明显不同 ,它是早期海生爬行动物进化的一个比较原始而孤立的新种类。它的发现对早期海生爬行动物进化多样性的认识具有十分重要的科学意义。
The specimen described in this paper was collected by Li Gui yuan from the grey black middle thin layered limestone beds of the Middle Triassic Yangliujing Formation at a quarry of Luyin Cement Plant some 150m west of Luyin village in Dingxiao Ecomomic Development Zone, Guizhou. It is a new genus and species of the marine reptile represented by the hind limbs, partial vertebrae and scattered ribs, which are briefly described as follows. Order Ichthyosauria (?) Family Dingxiaosauridac fam. nov. Genus Dingxiaosaurus gen. nov. Type species Dingxiaosaurus luyinensis sp.nov. Diagnosis Marine reptiles of moderate size. Hind limbs longer, larger and paddle shaped. Femur not expanded distally. Tibia and fibula elongated. Tarsals large, polygonally blocky, and arranged closely in two rows, three ones in the proximal, and four in the distal row of the tarsus. Digits five. Metatarsals elongated. Phalanges of Ⅰ-Ⅴ digits long and number obviously increased. Vertebrae longer and amphicoelous. Etymology Dingxiao and Luyin from the Chinese Phonetic Alphabet of the fossil producing district and village. Dingxiaosaurus luyinensis sp. nov. (Pl. Ⅰ, fig.1) Holotype Hind limbs, partial vertebrae and scattered ribs of a marine reptile. Diagnosis as for the genus (only species). Locality and horizon Luyin village in Dingxiao Ecomomic Development Zone, Guizhou; Middle Triassic Yangliujing Formation (Ladinian). Description (omitted here). Remarks The new genus Dingxiaosaurus, although based on the hind limbs, partial vertebrae and scattered ribs, is highly distinctive. The morphology and the structure of the limb bones show a blend of the characters of the primitive ichthyosaurs and the earliest plesiosaurs. The elongated tibia and fibula are very similar to those of the primitive ichthyosaurs, and the phalanges somewhat similar in shape and number to those of the earliest plesiosaurs. However, the new genus is different form all the known ichthyosaurid and plesiosaurid genera and species, and represents an isolated form of the early marine reptiles. It cannot be placed in any the known family of the ichthyosaurids and the plesiosaurids. Therefore we propose for it a new family Dingxiaosauridae. From the characters of the femur, tibia, fibula, and tarsals, it seems that Dingxiaosaurus shows closer affinity with the primitive ichthysaurs and remoter affinity with the earliest plesiosaurs.
出处
《高校地质学报》
CAS
CSCD
2002年第2期220-226,共7页
Geological Journal of China Universities
关键词
海生爬行动物
中三叠世
贵州兴义县
marine reptile
Middle Triassic
Xingyi County
Guizhou Province
