一个早期白时期的tribosphenic哺乳动物和metatherian进化
Zhe-Xi Luo1, Qiang Ji, John R Wible
1Carnegie Museum of Natural History, Pittsburgh, PA 15213, USA. luoz@carnegiemuseums.org
Science (New York, N.Y.)
|December 13, 2003
概括
来自中国的一种新化石哺乳动物,可以追溯到1.25亿年前,揭示了与有袋动物比胎盘动物更紧密的联系. 这一发现突显了早期哺乳动物的多样性,并表明亚洲是它们进化的关键中心.
科学领域:
- 古生物学的古生物学
- 哺乳动物进化 哺乳动物进化
- 中生代哺乳动物 中生代哺乳动物
背景情况:
- 早期哺乳动物之间的进化关系,特别是甲类动物和类动物,仍然是研究的关键领域.
- 早期白时期的化石为哺乳动物的多样化提供了关键的见解.
研究的目的:
- 为了描述一个新的boreosphenidan哺乳动物化石从中国的下白纪溪形成.
- 确定这个新分类的基因位置相对于metatherians和eutherians.
- 推断这个早期哺乳动物的古生态学和生物地理学含义.
主要方法:
- 分析衍生的骨特征,特别是脚形态.
- 遗传学分类是为了建立进化关系.
- 基于化石分布的古地理重建.
主要成果:
- 新的化石哺乳动物展示了一些特征,表明它与超级动物比与eutherians更为密切的关系.
- 它的年龄 (1.25亿年前) 将有袋动物亲属的骨记录推迟了5000万年.
- 独特的脚结构表明树木适应,这表明早期的类哺乳动物利用了各种生态.
结论:
- 这种化石支持了这样一个假设:在白纪早期,亚洲是早期甲动物和动物多样化的主要中心.
- 早期的皇冠人表现出显著的生态多样性,包括树木生活方式.
- 这一发现显著提高了我们对早期哺乳动物进化和生物地理学的理解.
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