ABSTRACT The male reproductive system of Amazon freshwater crabs Sylviocarcinus pictus and Dilocarcinus pagei were described and compared in terms of anatomy and histochemistry In addition, sperm transfer experiments of D. pagei with sequential copulations were performed and the anatomy of the seminal receptacle was checked. The anatomy of the male reproductive system of both species is an inverted ‘U’ shape, connected by the testes, from which the pair of vas deferens divided into anterior, median and posterior regions depart. Sylviocarcinus pictus and D. pagei revealed coenospermia, which differed from the families of freshwater crabs in Southeast Asia. The histochemical composition of the seminal fluid is similar in both Trichodactylidae, following the pattern described for most Brachyura. Through the copulation experiments and anatomical results, these animals do not show a sperm plug, but rather form different sperm packs when engaging in multiple copulations with different males.

中文翻译：

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对亚马逊两只淡水蟹雄性生殖系统的调查：是否存在精子栓塞或精子包形成？

摘要 描述了亚马逊淡水蟹Sylviocarcinus pictus 和Dilocarcinus pagei 的雄性生殖系统，并在解剖学和组织化学方面进行了比较。此外，还进行了D. pagei 顺序交配的精子转移实验，并检查了精囊的解剖结构。两个物种的雄性生殖系统的解剖结构都是倒“U”形，由睾丸连接，分为前、中、后区域的一对输精管从睾丸分离。Sylviocarcinus pictus 和 D. pagei 揭示了异精子症，这与东南亚的淡水蟹科不同。精液的组织化学成分在两种 Trichodactylidae 中都相似，遵循大多数 Brachyura 描述的模式。