Middle Jurassic spinicaudatan Shizhuestheria from the Sichuan Basin and its ontogenetic implication  

作　　者：HIRANO Hiromichi KOZAI Takeshi SAKAI Takashi 

机构地区：[1]Department of Earth Sciences, School of Education, Waseda University, Tokyo 169-8050, Japan [2]Laboratory Geosciences, Faculty of Science, Naruto University of Education, Tokushima 772-8502, Japan [3]Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 810-8560, Japan

出　　处：《Science China Earth Sciences》2009年第12期1962-1968,共7页中国科学（地球科学英文版）

基　　金：Supported by Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. KZCX2-YW-154);Regional Research Project of Shehong, Sichuan (Grant No. 07D0020201);National Natural Science Foundation of China (Grant No. 40572005);Japan Society for the Promotion of Science (ID No. L09522);State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing (Grant Nos. 073106, 20082103)

摘　　要：The diagnosis of the Middle Jurassic spinicaudatan genus Shizhuestheria is revised following the re-examination under a scanning electron microscope of a type specimen from Yanxi of Shizhu, and the newly collected specimens from Xintiangou of Chengjiang Town, Beibei, Chongqing. Small-sized reticulations occur not only in the middle-sized reticulations on growth bands on the dorsal side of the carapace, but also on growth bands on the ventral side of the carapace, which have been overlooked in the original description. The shift from wide dorsal growth bands to narrow ventral ones might indicate an onset of sexual maturity, and the transition in biological priorities from rapid juvenile growth to reproductive activities.The diagnosis of the Middle Jurassic spinicaudatan genus Shizhuestheria is revised following the re-examination under a scanning electron microscope of a type specimen from Yanxi of Shizhu, and the newly collected specimens from Xintiangou of Chengjiang Town, Beibei, Chongqing. Small-sized reticulations occur not only in the middle-sized reticulations on growth bands on the dorsal side of the carapace, but also on growth bands on the ventral side of the carapace, which have been overlooked in the original description. The shift from wide dorsal growth bands to narrow ventral ones might indicate an onset of sexual maturity, and the transition in biological priorities from rapid juvenile growth to reproductive activities.

关 键 词：spinicaudatan Middle JURASSIC ONTOGENY BIOSTRATIGRAPHY SICHUAN Basin 

分 类 号：Q911[天文地球—古生物学与地层学]