来自南美洲白纪晚期的高度专业化的哺乳动物头骨
Guillermo W Rougier1, Sebastián Apesteguía, Leandro C Gaetano
1Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40202, USA. grougier@louisville.edu
Nature
|November 5, 2011
概括
新的化石发现揭示了南美洲早期哺乳动物的多样性. 这些古老的干类动物,来自白纪晚期,表现出独特的特征,填补了化石记录中的重大空白.
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:
- 干类动物是一种已灭绝的哺乳动物群体,是现代有袋动物和胎盘动物的祖先.
- 以前,在白纪晚期之前,干类化石很少,这阻碍了对它们的起源和多样化的理解.
- 南美干类动物在白纪晚期是特有和多样化的,但早期的进化历史仍然不清楚.
研究的目的:
- 描述来自南美洲早期晚白纪的第一个哺乳动物遗骸.
- 调查干类植物的起源和早期多样化.
- 为了记录中生代哺乳动物的头骨形态和生态多样性.
主要方法:
- 描述了两个部分头骨和一个衍生干类动物的下巴.
- 分析独特的牙和头骨特征,包括单根牙和双根前牙.
- 与来自劳拉西亚和其他中生代哺乳动物的已知罗纪干类动物进行比较.
主要成果:
- 发现一种衍生型干体,具有新的牙和头骨特征,包括长长的嘴巴和大狗.
- 新的哺乳动物展出了将其与劳拉西亚干类动物联系在一起的特征,同时展示了独特的专业化.
- 这些化石仅代表了刚德瓦纳白纪的第二只哺乳动物头骨,弥合了6000万年的差距.
结论:
- 这些发现突显了白纪期间南美干类动物群的特有性和多样性.
- 新的标本揭示了非tribosphenic哺乳动物中意想不到的形态和生态多样性.
- 这一发现显著提升了我们对刚德瓦纳早期哺乳动物进化的理解.
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