Embryos, polyps and medusae of the Early Cambrian scyphozoan Olivooides
Embryos, polyps and medusae of the Early Cambrian scyphozoan Olivooides
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DOI：
10.1098/rspb.2013.0071
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发表时间：
2013-04-22
影响因子：
4.7
通讯作者：
Donoghue, Philip C. J.
中科院分区：
文献类型：
--
作者：
Dong, Xi-Ping;Cunningham, John A.;Donoghue, Philip C. J.
早寒武世生物Olivoides从胚胎和胚胎后阶段都是已知的，因此，它有可能在动物身体计划建立时产生对发育进化的重要见解。然而，这种潜力只有在Olivooides的系统发育关系受到限制的情况下才能实现。由于缺乏内部解剖学知识和已知发育阶段的有限范围，Olivooides的亲和力已被证明是有争议的。在这里，我们描述了罕见的胚胎标本，其中内部解剖特征被保存。我们还提出了一个更完整的序列的Olivooides，包括相关的标本，我们解释为萌芽ephyelae（少年水母），所有这些都显示出一个明确的pentaradial对称的发育阶段。在刺胞动物解释的框架内，新的数据有助于确定Olivoides到scyphozoan干组的系统发育位置。关于Olivoides的scalidophoran或棘皮动物亲缘关系的假设可以被拒绝。
The Early Cambrian organism Olivooides is known from both embryonic and post-embryonic stages and, consequently, it has the potential to yield vital insights into developmental evolution at the time that animal body plans were established. However, this potential can only be realized if the phylogenetic relationships of Olivooides can be constrained. The affinities of Olivooides have proved controversial because of the lack of knowledge of the internal anatomy and the limited range of developmental stages known. Here, we describe rare embryonic specimens in which internal anatomical features are preserved. We also present a fuller sequence of fossilized developmental stages of Olivooides, including associated specimens that we interpret as budding ephyrae (juvenile medusae), all of which display a clear pentaradial symmetry. Within the framework of a cnidarian interpretation, the new data serve to pinpoint the phylogenetic position of Olivooides to the scyphozoan stem group. Hypotheses about scalidophoran or echinoderm affinities of Olivooides can be rejected.