阿根廷的化石重写了一个令人困惑的恐龙群的进化历史
Peter J Makovicky1,2,3, Jonathan S Mitchell4, Jorge G Meso5
1Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN, USA. pmakovic@umn.edu.
Nature
|February 25, 2026
概括
这项研究揭示,阿尔瓦雷斯类恐龙很可能起源于潘盖亚,早期的进化是由维卡里安斯驱动的,而不是小型化. 新的南美化石挑战了关于阿尔瓦雷斯类生物进化和分布的先前假设.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 生物地理学是生物地理学.
背景情况:
- 阿尔瓦雷斯类是从罗纪到白纪时期的小型热足类恐龙,已知来自亚洲和南美洲.
- 晚白时期的阿尔瓦雷斯类动物有专门的挖掘前肢,被认为是食生物,有假设表明进化微型化.
- 碎片化的南美种类以前被认为是相对于亚洲的帕维库索里纳的类型,分散解释了它们的分布.
研究的目的:
- 描述一个新的,完整的,小的南美阿尔瓦雷斯类动物,Alnashetri cerropoliciensis.
- 重新评估南美阿尔瓦雷斯类的遗传位置及其生物地理历史.
- 修订阿尔瓦雷斯类动物体型进化的模型.
主要方法:
- 来自南美洲的一种新的阿尔瓦雷斯类化石骨的描述.
- 植物遗传学分析包括新的和现有的阿尔瓦雷斯类种群.
- 生物地理分析以推断祖先分布和进化历史.
主要成果:
- 阿尔纳谢特里 (Alnashetri cerropoliciensis) 被描述为迄今为止最完整和最小的南美阿尔瓦雷斯类动物.
- 遗传学分析将Alnashetri置于基底非阿尔瓦雷斯类动物中,使南美种类成为多种类.
- 生物地理分析表明Alvarezsauroidea的Pangaean起源,其代名词塑造了早期的进化.
- 证据支持在狭窄的身体尺寸范围内重复进化,这与一致的进化微型化的假设相矛盾.
结论:
- 阿尔纳谢特里在体型较大的亲属中早期的分支驳斥了进化迷你化作为阿尔瓦雷斯类进化的主要驱动因素.
- 替代性,而不是分散,可能主导了阿尔瓦雷兹sauroidea的早期生物地理历史.
- 这项研究修订了我们对阿尔瓦雷斯沙罗伊德类生物发育,生物地理和身体尺寸进化的理解.
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