Laboratório de Ecologia e Evolução, Instituto Butantan, São Paulo, Brazil.
Departamento de Biologia, Universidade Estadual Paulista (UNESP), Instituto de Biociências, Letras e Ciências Exatas (IBILCE), São Paulo, Brazil.
Anat Rec (Hoboken). 2018 Nov;301(11):1936-1943. doi: 10.1002/ar.23904. Epub 2018 Oct 5.
The processes of follicular development, ovulation, egg capture, and egg transport vary among vertebrates. Therefore, analysis of the reproductive tract of several lineages is needed for understanding the evolutionary changes of the reproductive system. In turtles, the ovulated eggs are released into the coelomic cavity and taken up by one of the two oviducts, a phenomenon called extrauterine migration of eggs. However, the process of egg uptake in lizards is different. The egg is ovulated directly into the infundibulum, and oocyte uptake by the contralateral oviduct rarely occurs. The same pattern has been hypothesized to occur in snakes. To test this hypothesis, we analyzed the reproductive tract of female Micrurus corallinus preserved in zoological collections. We examined the anatomical characteristics of the infundibulum and ovary and compared the reproductive output between the ovaries to verify the mechanism of egg capture and the anatomical viability of extrauterine migration of eggs. The reproductive output of the right ovary was higher than that of the left ovary, and the higher number of eggs in the right oviduct is due exclusively to the production of the ipsilateral ovary. Several anatomical features prevent extrauterine migration of eggs, including the asymmetry of the reproductive system, the arrangement of the ovarian follicles in a single row, and the formation of a wrapping around the ovary and infundibulum by the visceral pleuroperitoneum membrane (preventing against ectopic eggs). Therefore, the hypothesis of egg capture by the contralateral oviduct is anatomically infeasible in M. corallinus and possibly in other snakes. Anat Rec, 301:1936-1943, 2018. © 2018 Wiley Periodicals, Inc.
滤泡发育、排卵、卵子捕获和卵子运输的过程在脊椎动物中各不相同。因此，需要分析几个谱系的生殖道，以了解生殖系统的进化变化。在海龟中，排卵的卵子被释放到体腔中，并被两条输卵管之一摄取，这一现象称为卵子的子宫外迁移。然而，蜥蜴的卵子摄取过程则不同。卵子直接排入漏斗，很少发生对侧输卵管摄取卵母细胞的情况。据推测，这种模式也发生在蛇类中。为了验证这一假说，我们分析了保存在动物收藏中的雌性 Micrurus corallinus 的生殖道。我们检查了漏斗和卵巢的解剖特征，并比较了卵巢之间的生殖输出，以验证卵子捕获的机制和卵子子宫外迁移的解剖可行性。右侧卵巢的生殖输出高于左侧卵巢，右侧输卵管中更多的卵子仅归因于同侧卵巢的产生。一些解剖特征阻止了卵子的子宫外迁移，包括生殖系统的不对称、卵巢滤泡呈单行排列以及内脏胸膜腹膜围绕卵巢和漏斗形成包裹（防止异位卵子）。因此，在 M. corallinus 以及可能在其他蛇类中，对侧输卵管摄取卵子的假说在解剖学上是不可行的。解剖学记录，301:1936-1943, 2018. © 2018 Wiley Periodicals, Inc.
