骨微观结构支持中生代起源的半水生洞穴生活方式在单体动物 (哺乳动物) 中
Suzanne J Hand1, Laura A B Wilson1,2,3, Camilo López-Aguirre4,5,6
1School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW 2052, Australia.
概括
化石证据表明,早期的单体动物,如新分析的Kryoryctes cadburyi,是半水生挖掘者. 这支持了一个假设,即两动物的生活方式是所有活着的单体动物的祖先.
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:
- 单体动物 (白鱼和鱼) 是唯一活着的产卵哺乳动物.
- 单极体在形态和生态上是多样化的.
- 由于缺乏化石证据,从半水生祖先的鱼的进化起源受到争议.
研究的目的:
- 为了研究单的进化历史.
- 为了测试埃基德纳从半水生祖先进化而来的假设.
- 分析早期白纪早期哺乳动物Kryoryctes cadburyi的遗传位置和生活方式.
主要方法:
- 哺乳动物形状的536个字符形态矩阵的家族遗传分析.
- 骨形态和微观结构的三维比较分析.
- 基于骨分析的Kryoryctes cadburyi生活方式的重建.
主要成果:
- Kryoryctes cadburyi被放置为一个茎单体.
- 克里奥里克斯与鱼有相似之处,但表现出在白类动物中发现的半水生专业化.
- 有证据表明,克里奥里克特斯是一名半水生挖掘者.
结论:
- 单体动物在中生代首次发展出两生活方式.
- 一种半水生挖洞生活方式很可能是单体动物的祖先.
- 类动物的血统显示了长期的利基保守主义,而类动物则代表了以后回归到陆地生命.
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