部落类哺乳动物的双重起源
Z X Luo1, R L Cifelli, Z Kielan-Jaworowska
1Section of Vertebrate Paleontology, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania 15213, USA.
Nature
|May 9, 2001
概括
对于哺乳动物进化至关重要的三角牙,两次独立进化. 这挑战了这些复杂的牙在古代哺乳动物的单一起源的想法.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 哺乳动物解剖学 哺乳动物解剖学
背景情况:
- 复杂的tribosphenic牙是有袋动物,胎盘动物及其亲属的特征,被认为是它们多样化的关键.
- 最近在贡德瓦纳地区发现的古老的,先进的哺乳动物挑战了传统的Laurasian起源假设的tribosphenic哺乳动物.
- 以前的假设提出了一个单一的进化起源的tribosphenic.
研究的目的:
- 研究哺乳动物中的tribosphenic的进化起源和生物地理.
- 根据新的化石证据,重新评估具有tribosphenic牙的哺乳动物的单.
主要方法:
- 遗传学分析包括新发现的化石种类.
- 摩尔结构的形态测量分析.
主要成果:
- 带有tribosphenic牙的哺乳动物不是单体,表明多个独立的起源.
- 在罗纪/白纪早期,tribosphenic牙两次独立进化.
- 两个不同的分类,澳大利亚 (Gondwanan,包括单体动物) 和北方 (Laurasian,包括有袋动物和胎盘动物),分别开发了这些牙.
结论:
- 复杂的tribosphenic摩尔结构在不同的哺乳动物血统中演变趋同.
- 这一发现需要对哺乳动物进化史和生物地理模型进行修订.
- 哺乳动物的多样化涉及关键牙科创新的独立进化,跨越不同的地理来源.
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