Paraprososthenia yunjian Xiang, He, Lv & Chen 2025, sp. nov.

Paraprososthenia yunjian Xiang, He, Lv & Chen, sp. nov. https://zoobank.org/ urn:lsid:zoobank.org:act: CDEF35B6-5F9C-4EF8-9419-F76445485069 Fig. 2 E, Fig. 3 K-M Material examined. Holotype: XHQ 24010501, shell height 22.0 mm. Zhongshu Town, Luliang County, Qujing City, Yunnan Province, China, 25.02°N, 103.66°E, June 2021, collected by Yue-Ming He and Hong-Quan Xiang (Fig. 1). Paratypes: 2 specimens, XHQ 24010502-03, shell height 20.0-25.0 mm, June 2023, locality and habitat same as holotype. Diagnosis. Shell small, elongate conic, white, with eleven to thirteen whorls, the whorls with very obvious keels on the shoulders, aperture ovate, inner lip thickened. Description. Shell small, but solid, elongate conic, white, with eleven to thirteen whorls, including two protoconch whorls, teleoconch whorl inflated; third to fifth whorls with very week keels on the shoulders; other whorls with very obvious keels on the shoulders; body whorls not swollen. Apex obtuse. Shell surface with fine growth lines, the whorls with very obvious keels on the shoulders. Umbilicus narrow and small, base with one keel around umbilical area. Aperture ovate, inner lip thickened and smooth, outer lip thickened. Differential diagnosis. Compared with P. costata and P. constricta, Paraprososthenia yunjian sp. nov. shell surface lacks nodules and with very obvious keels on the shoulders. Compared to P. gredleri, the shell of Paraprososthenia yunjian sp. nov. is larger, with more whorls, and more pronounced keels. Compared with P. jinxi sp. nov., P. bronyaae sp. nov. and P. bicarinata sp. nov., Paraprososthenia yunjian sp. nov. with only one keels on the shoulders. Etymology. The species name " yunjian " derives from a Chinese term describing the morphological features of a cloud, typically referring to the upper edge or appearance of a cloud, especially those parts that extend outward resembling shoulders. Here, it is used to describe the keel structures of this species. We suggest the Chinese common name as " 云ẽ川ϐ ". Distribution and ecology. This species is only found in the lake sediments of Lake Lulianghai in Luliang, Yunnan Province.