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古脊椎动物学报 ›› 2009, Vol. 47 ›› Issue (1): 1-8.

• 古脊椎动物学报 •    下一篇

短吻贫齿龙(双孔亚纲: 海龙目):头后骨骼及系统关系研究

吴肖春, 程延年, 佐藤环, 单希瑛   

  • 出版日期:2009-03-15 发布日期:2009-03-15

MIODENTOSAURUS BREVIS CHENG ET AL., 2007 (DIAPSIDA: THALATTOSAURIA): ITS POSTCRANIAL SKELETON AND PHYLOGENETIC RELATIONSHIPS

WU Xiao-Chun CHENG Yen-Nien SATO Tamaki SHAN Hsi-Yin   

  • Published:2009-03-15 Online:2009-03-15

摘要: 短吻贫齿龙是根据一保存较完整的头骨和下颌标本建立的;标本采自贵州关岭地区三叠系法郎组灰岩。对其头后骨骼进行了详细描述。短吻贫齿龙在肩带的乌喙骨和间锁骨及腰带的肠骨显示了与众不同的特征,例如: 紧靠肩臼后方乌喙骨有一明显的凹,间锁骨后半部比前部要窄很多,及肠骨背突末端加宽等。头骨进一步细修表明,其中一些部位需要进行重新记述。依据头后骨骼和头骨中的新信息,对短吻贫齿龙的特征作了修订。系统关系分析 表明,贫齿龙是个askeptosaurid,其下颌宽大于长的反关节突和肱骨缩小的三角- 胸大肌嵴表明它与产自瑞士和意大利的Askeptosaurus 关系最近。

Abstract:  Miodentosaurus brevis was first established on the basis of the skull and mandible of a fairly preserved skeleton from the Triassic Falang Formation, Guanling area, GuizhouProvince. The description of the postcranial skeleton reveals that M. brevis is also distinct in the morphology of its girdle elements, such as the coracoid with a small embayment just posterior to the glenoid, interclavicle becoming much narrower posteriorly than anteriorly, and the ilium having a dorsal blade with a expanded distal end. With a further preparation, some of the skull anatomies are redescribed. Based on new information from both skull and the postcranial skeleton, the diagnosis of the taxa is revised. A phylogenetic analysis suggests thatM. brevis is an askeptosauroid, closely related to Askeptosaurus from Switzerland and Italy on the basis of two unequivocal synapomorphies, a retroarticular process broader than long and a reduced deltopectoral crest in the humerus.