在早期坎布里亚时代的节肢动物中,复杂的大脑和光叶
Xiaoya Ma1, Xianguang Hou, Gregory D Edgecombe
1Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, China. x.ma@nhm.ac.uk
Nature
|October 13, 2012
概括
特殊的坎布里亚化石揭示了早期节肢动物的复杂大脑,挑战了以前的进化模型. 这一发现为理解关节动物神经系统进化和行为提供了至关重要的化石证据.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 神经科学是一个神经科学.
背景情况:
- 了解关节动物的进化关系在很大程度上依赖于神经系统数据.
- 神经组织的化石保存很少见,限制了对早期关节动物感觉和运动能力的洞察.
- 以前对早期节肢动物神经系统的分析主要集中在外部特征上.
研究的目的:
- 研究来自坎布里亚时期的干群关节动物Fuxianhuia protensa的神经解剖学.
- 为关节动物神经系统进化提供令人信服的化石证据.
- 解决关于昆虫大脑祖先状态的争论.
主要方法:
- 在Fuxianhuia proteensa.中,化石神经组织 (大脑和视叶) 的特殊保存.
- 详细分析神经解剖结构,包括光学中心,deutocerebrum和tritocerebrum.
- 与现存的节肢动物群体 (Malacostraca,Insecta,Branchiopoda) 的比较神经解剖学分析.
主要成果:
- 福西安胡亚 (Fuxianhuia protensa) 呈现出一个三部分前胃形大脑,有三个嵌套的光学中心,类似于现存的Malacostraca和Insecta.
- 分脑被天线神经化,并确定了一个三脑元件.
- 早期节肢动物的复杂大脑结构表明,复杂的视觉行为是可能的.
- 福西安胡亚的神经解剖学支持克拉迪斯蒂克分析,表明Branchiopoda是从一个类似马拉科斯特拉卡的祖先进化而来的,随后的大脑简化.
结论:
- 复杂的Fuxianhuia protensa的大脑表明,复杂的神经系统存在于早期分离的关节动物中.
- 这种化石证据挑战了分子分析,这表明Hexapoda的祖先状态更简单.
- 复杂大脑的早期进化可能推动了坎布里亚节足动物的多功能视觉行为.
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