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来自坎布里亚的原始软体头足动物
Martin R Smith1, Jean-Bernard Caron
1Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 3G5, Canada.
Nature
|May 28, 2010
概括
早期的头足动物,如Nectocaris,缺乏贝,生活在坎布里亚时期. 这一发现将头足动物的化石记录推迟了3000万年,揭示了它们的早期进化.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 海洋生物学 海洋生物学
背景情况:
- 伯吉斯页岩沉积物保存了早期动物的身体图案.
- 早期的头足动物进化,特别是螺类动物,人们对其了解甚微.
- Nectocaris pteryx是一个有问题的化石,来自中坎布里亚时期.
研究的目的:
- 将Nectocaris pteryx重新解释为一个原始的头足动物.
- 研究头足动物的早期进化及其身体计划.
- 将头足动物的化石记录延伸到坎布里亚纪.
主要方法:
- 对来自伯吉斯页岩的Nectocaris pteryx新化石材料的分析.
- 尼克托卡里斯和其他早期坎布里亚系的比较形态.
- 遗传学分析以确定Nectocarididae在头足动物中的位置.
主要成果:
- Nectocaris pteryx被重新解释为一个干群,非矿物化的头足动物.
- 尼克托卡里斯 (Nectocaris),佩塔利利姆 (Petalilium) 和维图斯托弗米斯 (Vetustovermis) 组成了尼克托卡里斯 (Nectocarididae) 类.
- 原始的头足动物缺乏外,是超的,并拥有用于喷气推进的漏斗.
结论:
- 头足动物的化石记录延伸了3000多万年进入坎布里亚纪.
- 喷气推进在头足动物获得矿物化外之前就已经进化了.
- 坎布里亚时期很可能为甲型头足动物的奥尔多维纪多样化提供了一个"保险丝".
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