LYSTROSAURUS GEORGI, A DICYNODONT FROM THE LOWER TRIASSIC OF RUSSIA
LYSTROSAURUS GEORGI, A DICYNODONT FROM THE LOWER TRIASSIC OF RUSSIA
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格奥尔吉水龙，一种来自俄罗斯下三叠统的二齿兽类
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
M. Benton
中科院分区：
文献类型：
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作者：
M. V. Surkov;N. N. Kalandadze;M. Benton
摘要首次描述了俄罗斯莫斯科盆地最下部三叠系中的柳龙头骨。本种保持在前颌和腭骨之间的接触，并以狭窄和拉长的坐骨为特征，为本种的自形。利用18个颅后特征对27个二叠纪和三叠纪Diynodon分类群进行的系统发育分析证实了最近的其他假说，但不支持Cistecephalus和Kingoria之间的密切关系。与肩带和前肢相比，骨盆和股骨特征的同质性水平较低，表明前者比后者更好地记录了异常牙齿的演化模式。对特征变化的分析表明，二齿齿后颅骨的一个总的进化趋势与获得半捕鲸运动有关。
Abstract The postcranial skeleton of Lystrosaurus georgi from the lowermost Triassic of the Moscow Basin, Russia, is described for the first time. This species retains contact between the premaxillae and palatine and is characterized by a narrow and elongated ischium, an autapomorphy for this species. Phylogenetic analysis of 27 Permian and Triassic dicynodont taxa using 18 postcranial characters confirms other recent hypotheses, but does not support a close relationship between Cistecephalus and Kingoria. The low homoplasy level among characters of the pelvis and femur, compared with the shoulder girdle and forelimbs, suggests that the former region documents the pattern of anomodont evolution better than the latter. Analysis of character changes revealed that a general evolutionary trend in the dicynodont postcranium relates to acquisition of semisprawling locomotion.