四川盆地剑龙类腰带演化

Evolution of Pelvic Girdles of Stegosaurus in the Sichuan Basin

四川盆地是中国剑龙类恐龙化石产出的集中地,主要包括华阳龙、沱江龙、巨棘龙、重庆龙、嘉陵龙、营山龙6属。除嘉陵龙外,另外5属均有腰带结构保存。剑龙类腰带是除了骨板外另一个重要的鉴定特征。该五属分布在4个连续的化石层,形成四川盆地的侏罗纪剑龙一条连续生长线。剑龙类腰带特征主要体现在髂骨、坐骨和耻骨的形态,根据其特征,可找到剑龙类从比较原始类型到进步类型的演化关系。四川盆地剑龙类有一个从华阳龙-重庆龙-巨棘龙-沱江龙-营山龙的演化过程,太白华阳龙是最原始的剑龙类,巨棘龙继承了部分原始性状,但它比华阳龙更为进步,巨棘龙应该是处于华阳龙和沱江龙之间的一个过渡类型,且与沱江龙的亲缘关系更近,是一类进化中的剑龙,营山龙位于四川盆地剑龙类演化的顶端。

Stegosaurs fossils in China occur mainly in the Sichuan basin,including 6 main genera:Huayangosaurus,Tuojiangosaurus,Gigantspinosaurus,Chungkingosaurus,Chialingosaurus,and Yingshanosaurus.All of them have pelvic girdles except Chialingosaurus.In addition to bone plates,stegosaurs pelvic girdle is an important identification characteristic.The five genera above are distributed over 4 successive fossil beds,allowing the Jurassic stegosaurus to have a continuous growth line.According to these characteristics,stegosaurs evolutionary relationship,from primitive to progressive type,has been found.The stegosaurs in the Sichuan basin has an evolutionary process,from Huayangosaurus,Chungkingosaurus,Gigantspinosurus,Tuojiangosaurus to Yingshanosaurus which shows that Huayangosaurus is still the most primitive stegosaurus.Gigantspinosurus,one of the evolving stegosaurs,should be the transitional type between the Huayangosaurus and Tuojiangosaurus,and it's a closer relative to Tuojiangosaurus.Yingshanosaurus is at the top of stegosaurs evolution in the Sichuan basin.