一个中三叠纪的干和体图的演变
Rainer R Schoch1, Hans-Dieter Sues2
1Staatliches Museum fur Naturkunde Stuttgart, Rosenstein 1, D-70191 Stuttgart, Germany.
Nature
|June 25, 2015
概括
一种新的化石爬行动物,Pappochelys,从三纪中期发现,为早期的乌进化提供了关键的见解. 这种过渡物种有助于弥合古代爬行动物和最早已知的海之间的差距.
科学领域:
- 脊椎动物动物学 脊椎动物动物学
- 古生物学的古生物学
- 进化生物学 进化生物学
背景情况:
- 由于相互矛盾的数据和化石差距,乌的进化历史受到争议.
- 关键的化石证据包括Odontochelys (部分外) 和Proganochelys (完全外).
- 尤诺多萨鲁斯是一个假设的早期茎,但在Odontochelys之前存在一个时间差距.
研究的目的:
- 为了描述一个新的化石爬行动物,Pappochelys,从三叠纪中期.
- 为了调查Pappochelys的遗传位置相对于其他早期的乌和茎乌.
- 提供关于乌外早期进化的新证据,以及对虫的亲和关系.
主要方法:
- 化石发现和挖掘Pappochelys从中三叠纪沉积物.
- 对Pappochelys的骨特征进行比较解剖分析,包括头骨,肋骨,胃骨和四肢腰带.
- 植物遗传学分析将Pappochelys纳入早期乌进化的现有数据集.
主要成果:
- 帕波切利斯可以追溯到大约2.4亿年前,从时间和结构上讲,它是Eunotosaurus和Odontochelys之间的中间物种.
- 与Odontochelys共享的特征包括四肢腰带形态和宽,T形的树干肋骨.
- 帕波赫利斯拥有胃甲,而不是塑,这表明通过胃融合形成塑.
- 头骨形态支持对海的形相亲关系.
结论:
- 在早期的乌进化过程中,Pappochelys代表了一个关键的过渡化石.
- 这些发现支持了这样一个假设:乌的胎盘是通过胃细胞的融合而演变的.
- 这一发现强化了乌的形祖先.
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