A poorly-known proboscidate leech species, Torix tukubana (Oka, 1935), in which the mid-body somites are biannulate dorsally and triannulate ventrally, is redescribed based on new specimens collected from its type locality, Mt. Tsukubasan in Honshu, Japan. The redescription provides the internal digestive and genital organs of T. tukubana for the first time. Our observation reveals that this species possesses equal-sized 1st–6th pairs of crop ceca that are nondiverticulated and tubular ovisacs running alongside the ventral nerve cord. Additionally, phylogenetic analyses using nuclear 18S rRNA, mitochondrial cytochrome c oxidase subunit I, 12S rRNA, tRNALeu, and NADH dehydrogenase subunit 1 markers reveal that T. tukubana is closely related to the Palearctic Hemiclepsis Vejdovský, 1884, in which the mid-body somites are triannulate.

中文翻译：

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基于拓扑型的水蛭 Torix tukubana (Hirudinida: Glossiphoniiformes: Glossiphoniidae) 的重新描述

一种鲜为人知的长鼻水蛭物种 Torix tukubana (Oka, 1935)，根据从其类型产地 Mt. 收集的新标本重新描述了其中体节背侧双环和腹侧三环的体节。日本本州的筑波山。重新描述首次提供了 T. tukubana 的内部消化和生殖器官。我们的观察表明，该物种拥有大小相同的第 1-6 对作物盲肠，它们是非憩室的管状卵囊，沿着腹神经索运行。此外，使用核 18S rRNA、线粒体细胞色素 c 氧化酶亚基 I、12S rRNA、tRNALeu 和 NADH 脱氢酶亚基 1 标记进行的系统发育分析表明，T. tukubana 与古北半球的 Hemiclepsis Vejdovský 密切相关，1884 年是三角形的。