A New Mamenchisaurid Dinosaur from the Middle Jurassic of Yuanmou,Yunnan Province, China  

作　　者：LU Junchang LI Tianguang ZHONG Shimin JI Qiang LI Shaoxue 

机构地区：[1]Institute of Geology, Chinese Academy of Geological Sciences. Beijing 100037, China [2]Chuxiong Museum, Chuxiong, Yunnan 675000, China [3]Yuanmou Museum, Yuanmou, Yunnan 651300, China

出　　处：《Acta Geologica Sinica(English Edition)》2008年第1期17-26,共10页地质学报（英文版）

摘　　要：A new mamenchisaurid dinosaur, Eomamenchisaurus yuanmouensis gen et sp. nov. is erected based on an incomplete skeleton from the Zhanghe Formation, the Middle Jurassic of Yuanmou, Yunnan Province. The new taxon is characterized by absence of pleurocoels in dorsal vertebrae and the dorsal verterbrae with slightly convex anterior articular surfaces, moderately concave posterior articular surfaces; the fourth trochanter is developed posteromedially on the femur; length ratio of the tibia to the femur is approximately 0.64; and the shaft of the ischium is rod-like. Two fused centra of the posterior dorsal vertebrae （the presumed 9th and the 10th dorsal vertebrae） are similar to those in other mamenchisaurid dinosaurs, including Mamenchisaurus hochuanesis, M. youngi and Chuanjiesaurus anaensis. Therefore, fusion of centra of the ninth and the tenth dorsal vertebrae can be recognized as a synapomorphic character of the Mamenchisauridae.A new mamenchisaurid dinosaur, Eomamenchisaurus yuanmouensis gen et sp. nov. is erected based on an incomplete skeleton from the Zhanghe Formation, the Middle Jurassic of Yuanmou, Yunnan Province. The new taxon is characterized by absence of pleurocoels in dorsal vertebrae and the dorsal verterbrae with slightly convex anterior articular surfaces, moderately concave posterior articular surfaces; the fourth trochanter is developed posteromedially on the femur; length ratio of the tibia to the femur is approximately 0.64; and the shaft of the ischium is rod-like. Two fused centra of the posterior dorsal vertebrae （the presumed 9th and the 10th dorsal vertebrae） are similar to those in other mamenchisaurid dinosaurs, including Mamenchisaurus hochuanesis, M. youngi and Chuanjiesaurus anaensis. Therefore, fusion of centra of the ninth and the tenth dorsal vertebrae can be recognized as a synapomorphic character of the Mamenchisauridae.

关 键 词：Eomamenchisaurus Mamenchisauridae SAUROPODA Middle Jurassic Yunnan Province 

分 类 号：Q915.6[天文地球—古生物学与地层学]