蒂卡塔利克花的轴骨架
Thomas A Stewart1, Justin B Lemberg2, Emily J Hillan2
1Department of Biology, The Pennsylvania State University, State College, PA 16802.
概括
蒂卡塔利克科的轴骨架显示,在肢体出现之前,在有的脊椎动物中演化出了专门的十字肋骨和头部移动性. 这一发现早于主要的脊椎变化和四肢起源.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 比较解剖学的比较解剖学
背景情况:
- 早期四足动物轴骨架的进化对于理解脊椎动物陆地适应至关重要.
- 四足动物亲属的轴骨的关键特征往往被掩盖,限制了对进化序列的理解.
- 从翅膀到四肢的脊椎动物的过渡涉及脊柱和骨盆腰带结构的显著变化.
研究的目的:
- 为了描述形的轴性骨架,形形的Tiktaalik roseae.
- 阐明四肢肢体进化之前的轴骨架专业化的序列和功能上下文.
- 为了研究头部移动性,身体支和骨盆连接在早期四肢脊椎动物亲属的进化.
主要方法:
- 对Tiktaalik roseae的轴骨架进行了详细的形态分析.
- 与早期四肢形态动物和其他脊椎动物种群进行比较分析.
- 基于骨特征的运动和姿势的功能影响的重建.
主要成果:
- 蒂卡塔利克科植物表现出专门的圣肋,与早期四足形态动物不同,表明骨盆链接.
- 增加的头部移动性是由一个独立的基头-外头综合体,而不是一个天座-轴综合体.
- 新型肋骨类型和骨盆-轴柱连接的演变发生在主要的骨干脊椎变化和四肢起源之前.
结论:
- 特殊的圣肋骨和增强的头部移动性在有的脊椎动物中在四肢出现之前就已经演变了.
- 这些发现挑战了关于在到四肢过渡期间轴性骨架进化序列的先前假设.
- Tiktaalik roseae提供了对肢体脊椎动物最亲密的亲属的身体姿势和运动的关键见解.
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