德纪的关节胚胎和脊椎动物内部受精的起源
John A Long1, Kate Trinajstic, Zerina Johanson
1Museum Victoria, PO Box 666, Melbourne 3001, Victoria, Australia. jlong@museum.vic.gov.au
Nature
|February 27, 2009
概括
在Arthrodira鱼类中发现的化石胚胎揭示了内部受精和活产 (viviparity) 在早期的脊椎动物中很常见. 这挑战了关于古代脊椎动物繁殖策略的先前假设.
科学领域:
- 古生物学的古生物学
- 脊椎动物动物学 脊椎动物动物学
- 进化生物学 进化生物学
背景情况:
- 在化石记录中,生殖生物学证据很少.
- 之前的发现发现了ptyctodontids (Placodermi) 中的胚胎,这表明了冠状组Gnathostomata之外的活偶性.
- 甲鱼 (Placodermi) 是一个已经灭绝的装甲鱼类.
研究的目的:
- 报告在Arthrodira标本中发现胚胎.
- 为了提供证据,在这个多样化的斑皮动物群体内进行内部受精.
- 为了研究来自上代沃纪戈戈形成的Incisoscutum ritchiei的繁殖策略.
主要方法:
- 对Incisoscutum ritchiei标本的化石分析.
- 在 placoderms 和 chondrichthyans 骨盆腰带的骨比较分析.
- 人类遗传学解释解剖学相似之处.
主要成果:
- 在Arthrodira标本 (Incisoscutum ritchiei) 中发现了胚胎.
- 有证据表明,在这个群体中,内部受精和活偶性.
- 在Incisoscutum和phyllolepid arthrodires中的骨盆腰带表明骨盆被用于交配.
- 骨的相似性归因于融合进化 (同位素).
结论:
- 内部受精和活性在早期的体体中普遍存在.
- 这些发现扩大了我们对脊椎动物生殖进化的理解.
- 这项研究为Arthrodira.提供了第一个使用内部受精进行繁殖的证据.
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