来自中国的一种新型对称的哺乳动物及其对哺乳动物进化的影响
1Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing.
Nature
|November 21, 1997
概括
来自中国的一种保存得非常完善的对称的哺乳动物化石,为早期哺乳动物进化提供了新的见解. 这一发现揭示了主要哺乳动物血统与 marsupial 和胎盘分歧之前的骨发育之间的关系.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 哺乳动物学 哺乳动物学
背景情况:
- 对称的哺乳动物是现代有袋动物和胎盘动物的灭绝的亲属.
- 对于古老的类哺乳动物,包括对称类哺乳动物的化石证据往往是零碎的.
- 这一发现代表了迄今为止发现的最完整的对称龙化石.
研究的目的:
- 为了描述一个新的,特别保存的,来自中生代的对称牙哺乳动物.
- 研究早期哺乳动物血统之间的进化关系.
- 了解哺乳动物骨的进化和关键解剖特征.
主要方法:
- 对一个几乎完整的后骨和带有牙的部分头骨的分析.
- 遗传学分析以确定新分类的进化位置.
- 骨特征的比较解剖学研究,包括四肢姿势和内耳结构 (耳).
主要成果:
- 这种新分类是迄今为止发现的最完好保存的对称的哺乳动物,它提供了前所未有的解剖细节.
- 遗传学分析将这种对称体置于早期的therian辐射中,早于有袋动物和胎盘分歧.
- 类动物和多菌动物似乎比以前想象的更密切相关.
- 与大多数现存的therians相比,古老的therians表现出较少的偏前肢姿势.
- 古老的里亚人保留了一种原始的,类似手指的突起体,与衍生里亚人 (与单体合体) 完全卷起的耳不同.
结论:
- 这种化石显著增强了我们对早期类动物进化和哺乳动物多样化的理解.
- 这些发现支持类动物和多菌动物之间更紧密的关系.
- 这项研究阐明了哺乳动物骨的进化,包括四肢姿势和耳卷曲,突出了融合进化.
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