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意大利阿尔卑斯山的三叠纪中期揭示了的起源
Tiago R Simões1, Michael W Caldwell2,3, Mateusz Tałanda4
1Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada. tsimoes@ualberta.ca.
Nature
|June 1, 2018
概括
发现了一种古老的状虫, 这一发现有助于解决和蛇的进化起源, 调整形态和分子数据.
科学领域:
- 古生物学
- 进化生物学
- 杂草学
背景情况:
- 现代类动物 (类动物,蛇类动物,两类动物) 是一个高度多样化的四足动物群,具有悠久的进化历史.
- 由于化石差距很大,分类型的采样有限,以及有矛盾的基因学假设,人们对状动物的进化起源进行了辩论.
- 之前最古老的骨化石可以追溯到罗纪中期 (16800万年前).
研究的目的:
- 调查状动物的进化起源并解决遗传学上的不确定性.
- 利用来自爬行动物的高分辨率计算机断层扫描数据来澄清状动物的祖先.
- 将化石和现存的种类数据与形态和分子证据整合起来.
主要方法:
- 高分辨率的微焦X射线计算机断层扫描化石爬行动物Megachirella wachtleri.
- 构建一个综合的遗传学数据集,结合化石和现存的状物种.
- 根据各种最佳性标准对形态和分子数据进行分析,以评估介质关系.
主要成果:
- 梅加奇雷拉瓦克特莱里被认为是已知的最古老的状体,早于已知的化石7500万年 (三叠纪中期).
- 这一发现部分填补了化石的缺口,
- 现在的形态和分子数据都一致,表明是最早的冠状,而不是.
结论:
- 巨虫 (Megachirella wachtleri) 显著重塑了虫的基因组,并提供了早期虫进化的关键见解.
- 这些发现支持状动物的逐渐进化路径,并解决了长期存在的基因冲突.
- 差异时间估计表明类动物和其他类动物起源于波斯/三叠纪灭绝之前,三叠纪是辐射的时期.
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