Morphogenesis and phenotypic divergence in two developmental morphs of Streblospio benedicti (Annelida, Spionidae)
Morphogenesis and phenotypic divergence in two developmental morphs of Streblospio benedicti (Annelida, Spionidae)
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DOI：
10.1111/j.1744-7410.2010.00213.x
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发表时间：
2010-01-01
影响因子：
1.2
通讯作者：
Dufton, Megan
中科院分区：
文献类型：
--
作者：
Gibson, Glenys;MacDonald, Kristen;Dufton, Megan
海洋无脊椎动物幼虫的形态与卵大小和幼虫摄食方式密切相关。浮游营养型幼虫通常具有支持浮游摄食生活方式的一系列形态特征，而卵磷脂幼虫通常具有较大、蛋黄状的身体，并且在某些情况下，幼虫特征的表达减少。同源物种为分析早期形态发生提供了有趣的案例，因为单个物种产生了两种形态的幼虫。我们使用扫描电子显微镜或连续切片对活体个体进行观察，比较了异源环节动物 Streblospio benedicti 从承轮阶段到变态阶段的浮游营养型和卵磷脂营养型的形态发生。众所周知，该物种的交替发育形态的后代在大小、卵黄含量和幼虫刚毛的存在方面具有不同的形态。我们发现，形态之间的一些表型差异仅存在于一种形态中（例如，幼虫刚毛、前节和尾部的细菌细胞），但大部分表型差异是基于共享性状（例如，肠道和体腔）分化的异时性变化。从早期发育和变态过程中的结构和个体发育变化方面比较了两种形态的组织和器官发育。
The morphology of marine invertebrate larvae is strongly correlated with egg size and larval feeding mode. Planktotrophic larvae typically have suites of morphological traits that support a planktonic, feeding life style, while lecithotrophic larvae often have larger, yolkier bodies, and in some cases, a reduced expression of larval traits. Poecilogonous species provide interesting cases for the analysis of early morphogenesis, as two morphs of larvae are produced by a single species. We compared morphogenesis in planktotrophic and lecithotrophic morphs of the poecilogonous annelid Streblospio benedicti from the trochophore stage through metamorphosis, using observations of individuals that were observed alive, with scanning electron microscopy, or in serial sections. Offspring of alternate developmental morphs of this species are well known to have divergent morphologies in terms of size, yolk content, and the presence of larval bristles. We found that some phenotypic differences between morphs occur as traits that are present in only one morph (e.g., larval bristles, bacillary cells on the prostomium and pygidium), but that much of the phenotypic divergence is based on heterochronic changes in the differentiation of shared traits (e.g., gut and coelom). Tissue and organ development are compared in both morphs in terms of their structure and ontogenetic change throughout early development and metamorphosis.