完整的伊希约尼斯头骨照亮了鸟类头部的马赛克组合
Daniel J Field1,2, Michael Hanson1, David Burnham3
1Department of Geology & Geophysics and Peabody Museum of Natural History, Yale University, New Haven, CT, USA.
Nature
|May 4, 2018
概括
新的化石显示,古代鸟类Ichthyornis dispar拥有与现代鸟类相似的过渡和动力头骨,这表明鸟类养系统的早期演变. 这只鸟还保留了恐龙的肌,
科学领域:
- 古生物学
- 进化生物学
- 比较解剖学
背景情况:
- 与它们的恐龙祖先相比,现存的鸟类的头骨具有高度的变化, 它们的嘴巴没有牙, 运动系统复杂.
- 这些鸟类头骨特征的进化序列和早期发展在很大程度上仍然没有特征.
- 一种白纪晚期的有牙的鸟类Ichthyornis dispar占据了关键的遗传位置,保留了祖先的特征,同时接近现代鸟类的辐射.
研究的目的:
- 为了研究形态和ichthyornis的进化过渡.
- 通过新发现的和以前被忽视的化石样本重建Ichthyornis dispar的头骨.
- 了解鸟类食器,脑和肌的早期演变.
主要方法:
- 对四个新的三维保存标本的分析 Ichthyornis dispar.
- 高分辨率的计算机断层扫描 (CT) 来创建一个3D重建的Ichthyornis差头骨.
- 与现存的鸟类和化石恐龙头骨结构进行比较分析.
主要成果:
- 伊希约尼斯的鼻子很小,只限于尖,没有口腔架.
- 头骨表现出与现代鸟类相似的运动系统, 表明这种鸟类特征的早期演变.
- 尽管脑相对现代,但部仍保留着一个大型的恐龙引体室,还保留着祖先的上窗的遗迹.
结论:
- 鸟类养装置的关键组件,包括动体,比以前理解的要早,并且功能性地集成.
- 鸟类大脑的进化与祖先恐龙的肌和骨结构的保留同时发生.
- 它代表了原始和衍生的头骨特征的马赛克, 提供了对鸟类进化的节奏和模式的关键见解.
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