一个宏观的自由游泳水母从中坎布里亚 Burgess Shale
Justin Moon1,2, Jean-Bernard Caron1,2,3, Joseph Moysiuk1,2
1Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2.
Proceedings. Biological sciences
|August 2, 2023
概括
已知最古老的自由游泳水母, *Burgessomedusa phasmiformis*, 在坎布里亚时代的伯吉斯页岩化石中被发现. 这一发现揭示了鱼生命阶段的古老起源,支持早期的Medusozoa多样化.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 动物学 动物学
背景情况:
- 类动物代表了早期分离的动物类,自由游泳的水母阶段是Medusozoa的一个关键创新.
- 由于化石记录和分子数据的局限性,人们对鱼阶段的进化起源知之甚少.
- 以前对早期水母形状的化石解释已经被重新评估,其中一些被重新归类为ctenophores.
研究的目的:
- 描述一个新的化石物种, *Burgessomedusa phasmiformis*, 代表最古老的毫不含糊的宏观自由游泳水母.
- 为了确定动物王国内的 *Burgessomedusa phasmiformis* 的遗传位置.
- 提供关于Medusozoa早期进化和多样化的见解.
主要方法:
- 分析了来自中坎布里亚时代伯吉斯页岩的182个极其保存的"Burgessomedusa phasmiformis"化石.
- 化石标本的详细形态检查,包括雨结构和触角.
- 遗传学分析以确定 *Burgessomedusa phasmiformis* 的进化关系.
主要成果:
- 关于 *Burgessomedusa phasmiformis* gen. 和 sp. 的描述 它的特点是立方形的雨 (高达20厘米) 和许多短的触手.
- 遗传学分析将 * Burgessomedusa * 置于 Medusozoa 中,可能是 Cubozoa 或 Acraspeda 的一个干群.
- 这一发现证实了在坎布里亚中期出现了宏观的自由游泳水母,比以前确定的时间要早得多.
结论:
- *Burgessomedusa phasmiformis*为自由游泳水母生命阶段提供了最古老的直接化石证据.
- 这些发现支持Medusozoa的古老起源,并表明在前坎布里亚-坎布里亚过渡期间发生了显著的进化多样化.
- 这一发现挑战了先前对早期水母类化石的解释,并强调了特殊的化石保存对于理解进化历史的重要性.
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