Kristof Alen, de Oliveira André Luiz, Kolbin Konstantin G, Wanninger Andreas
Department of Integrative Zoology, University of Vienna, Vienna Austria.
Laboratory of Cell Differentiation, A.V. Zhirmunsky Institute for Marine Biology, Far East Branch of the Russian Academy of Sciences, Vladivostok Russian Federation.
J Zool Syst Evol Res. 2016 Feb 1;54(1):22-39. doi: 10.1111/jzs.12112.
Within Gastropoda, limpets (Patellogastropoda) are considered the most basal branching taxon and its representatives are thus crucial for research into evolutionary questions. Here, we describe the development of the neuromuscular system in cf. . In trochophore larvae, first serotonin-like immunoreactivity (lir) appears in the apical organ and in the prototroch nerve ring. The arrangement and number of serotonin-lir cells in the apical organ (three flask-shaped, two round cells) are strikingly similar to those in putatively derived gastropods. First, FMRFamide-lir appears in veliger larvae in the of the future adult nervous system including the cerebral and pedal ganglia. As in other gastropods, the larvae of this limpet show one main and one accessory retractor as well as a pedal retractor and a prototroch muscle ring. Of these, only the pedal retractor persists until after metamorphosis and is part of the adult shell musculature. We found a hitherto undescribed, paired muscle that inserts at the base of the foot and runs towards the base of the tentacles. An apical organ with flask-shaped cells, one main and one accessory retractor muscle is commonly found among gastropod larvae and thus might have been part of the last common ancestor.
在腹足纲动物中，帽贝（笠贝亚纲）被认为是最基部的分支类群，因此其代表物种对于进化问题的研究至关重要。在此，我们描述了cf.的神经肌肉系统的发育情况。在担轮幼虫中，最初的5-羟色胺样免疫反应性（lir）出现在顶器和原肠神经环中。顶器中5-羟色胺-lir细胞的排列和数量（三个烧瓶状、两个圆形细胞）与推测的衍生腹足纲动物中的那些细胞惊人地相似。首先，FMRF酰胺-lir出现在面盘幼虫中未来成体神经系统的 ，包括脑和足神经节。与其他腹足纲动物一样，这种帽贝的幼虫显示出一条主牵缩肌和一条副牵缩肌以及一条足牵缩肌和一个原肠肌环。其中，只有足牵缩肌持续到变态后，并成为成体壳肌肉组织的一部分。我们发现了一种迄今为止未描述过的成对肌肉，它插入到足部基部并向触手基部延伸。具有烧瓶状细胞的顶器、一条主牵缩肌和一条副牵缩肌在腹足纲幼虫中很常见，因此可能是最后一个共同祖先的一部分。
