对于早期有袋动物历史的Deltatheridium标本的影响
G W Rougier1, J R Wible, M J Novacek
1Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Kentucky 40292, USA. grougier@louisville.edu
Nature
|December 16, 1998
概括
蒙古新发现的Deltatheridium pretrituberculare化石揭示了早期哺乳动物进化的洞察力. 这些发现支持了与delta-theroidans的metatherian亲缘关系,澄清了早期的therian血统发展.
科学领域:
- 古生物学的古生物学
- 哺乳动物学 哺乳动物学
- 进化生物学 进化生物学
背景情况:
- 从有限的化石中已知的Deltatheroidans在早期哺乳动物中具有不确定的家族遗传位置.
- 之前的分类已经将它们分别识别为eutherians,基底转移体,或是两者的外组.
- 稀少的化石记录阻碍了对早期类动物进化的理解.
研究的目的:
- 描述来自蒙古白纪晚期的Deltatheridium pretrituberculare的两个新标本.
- 为了研究牙置换模式和/大脑基形态在基底三哺乳动物.
- 解决关于 deltatheroidan 亲缘关系和它们在早期哺乳动物进化中的作用的相互矛盾的假设.
主要方法:
- 描述了两个新的化石标本的Deltatheridium pretrituberculare.
- 分析牙置换,下和基本形态.
- 植物遗传学分析包含新的形态学数据.
主要成果:
- 新的标本提供了有关牙置换和牙形态的详细信息.
- 有证据支持甲类动物与 deltatheroidans 的亲缘关系.
- 在Deltatheridium中确定了牙置换和骨血管化的专门的有袋动物模式.
结论:
- 德尔塔泰罗伊达人被证实是基底甲基动物.
- 在Deltatheridium中,关键的形态特征是整个Metatheria的特征.
- 完整的化石标本对于理解哺乳动物早期进化事件至关重要.
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