Jawless land snail Sinorachis, a new bradybaenine genus from China (Eupulmonata, Camaenidae)

Zookeys. 2019 Dec 2:893:51-67. doi: 10.3897/zookeys.893.38445. eCollection 2019.


A new land snail species that represents a new genus is reported from Hubei, China. The snail has a conical shell with pits and/or granules on embryonic whorls and a smooth teleoconch with straight peristome. The head of the animal has a developed wart. The mantle lobe is only developed on the left side. At the front of the buccal mass there is no chitinous jaw that is without exception seen in Chinese camaenids. Its radular teeth are usually slender and tongue-shaped, not typical in bradybaenine snails. The genital system is typical of Bradybaeninae and is characterized by the absence of a membranous sac surrounding the terminal genitalia, penial caecum or flagellum; a well-developed penis sheath; a symmetrical dart sac apparatus; and one distally branched mucous gland. The new species Sinorachis baihu Wu & Chen, gen. and sp. nov., is assigned to the type species of the new genus, in which all the known Chinese Rachis species are included. Thereby, the new genus is composed of three species, namely Sinorachis onychinus (Heude), comb. nov., Sinorachis aureus (Heude), comb. nov. and the new species.

Chinese abstract从湖北报道了一个陆生贝类新物种并指定其为新属华霜螺属Sinorachis Wu & Chen, gen. nov. 的模式种。该属因生殖系统具有巴蜗牛亚科(坚螺科)的典型矢囊结构而被列入巴蜗牛亚科。模式种白虎华霜螺Sinorachis baihu Wu & Chen, gen. and sp. nov. 口球前端的颚片阙如,系已知中国的坚螺科中首个口球缺乏颚片的物种。此外,白虎华霜螺齿舌的齿多呈细舌状且排列紧密,与常见的巴蜗牛亚科的齿舌不同。华霜螺属的鉴别特征为:贝壳锥形;胚螺层具微小凹坑和/或颗粒;成螺光滑;壳口缘不反折。头瘤发达;外套膜左缘具小叶。颚片阙如。生殖系统基部膜囊缺乏;具交接器鞘;鞭状体无;矢囊器官对称;粘液腺一根、分支。几何形态学分析亦表明本属具有与霜纳螺Rachis Albers、中国艾纳螺各属及巴蜗牛亚科的拟锥螺Pseudobuliminus Gredler相异的贝壳特征。由之将中国原艾纳螺总科霜纳螺属的所有物种移入本新属。华霜螺属由爪华霜螺Sinorachis onychinus (Heude), comb. nov.、金华霜螺Sinorachis aureus (Heude), comb. nov. 与本新种组成。.

Keywords: Bradybaeninae; Enoidea; Hubei; taxonomy.