Shuiyu multicostata Xiang, He, Lu & Chen 2025, gen. et sp. nov.

Shuiyu multicostata Xiang, He, Lu & Chen, gen. et sp. nov. https://zoobank.org/ urn:lsid:zoobank.org:act: DCB6AECE-8601-4635-9917-565A73B35662 Fig. 2 H, Fig. 4 D-G Material examined. Holotype: XHQ 24010801, shell height 16.0 mm. Zhongshu Town, Luliang County, Qujing City, Yunnan Province, China, 25.02°N, 103.66°E, June 2022, collected by Yue-Ming He and Hong-Quan Xiang (Fig. 1). Paratypes: 3 specimens, XHQ 24010802-04, shell height 20.2-25.0 mm; 2 collected from the type locality, June 2022; 1 collected from the Lake Babuhai [八步海], Songming County [Ḇfi县], Kunming City [Zfi市], 25.27°N, 103.11°E, June 2021. Diagnosis. Shell small, elongate conic, grey, with nine whorls, the whorls with axial ribs, aperture ovate, inner lip thickened. Description. Shell small, translucent, but solid, elongate conic, grey, with nine spiral whorls, including two protoconch whorls, teleoconch whorl inflated; third whorls smooth; fourth whorls with six to eight weak axial ribs; other whorls with thirteen to twenty-one axial ribs, body whorl not swollen. Apex obtuse. Umbilicus narrow and small, base white and with one weak keel around umbilical area. Aperture ovate, less than half of shell in height, inner lip thickened and smooth, outer lip reflexed and thickened. Differential diagnosis. Compared with S. rillionaae gen. et sp. nov., Shuiyu multicostata gen. et sp. nov. has a smaller shell and less axial ribs. Additionally, the axial ribs on the body whorl of S. multicostata gen. et sp. nov. are less pronounced than those of S. rillionaae gen. et sp. nov .. Etymology. The species name "multicostata " for many ribs on shell. We suggest the Chinese common name as " ľb水玉Dz ". Distribution and ecology. This species is only found in the lake sediments of Lake Lulianghai and Lake Babuhai, Yunnan Province.