Shuiyu rillionaae He, Xiang & Chen, gen. et sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act: 652B304D-C127-49A3-9528-6B17FDC45D1C

Fig. 2 G, Fig. 4 A-C

Material examined. Holotype: XHQ 24010701, shell height 19.5 mm, Haijing [海ae], Lake Fuxian [抚 仙¾], Yuxi City [玉※市], Yunnan Province, China, 24°37′22″N, 102°51′32″E, February 2025, collected by Yue-Ming He, Hong-Quan Xiang and Chong-Ye Li (Fig. 1).

Paratypes: 2 specimens, XHQ 24010702-03, shell height 16.3–21.0 mm, February 2025, locality and habitat same as holotype.

Diagnosis. Shell small, elongate conic, light grey, with eight to nine whorls, whorls with eleven to fourteen axial ribs. Umbilicus narrow or absent, outer lip roll outward and thickened.

Description. Shell small, thick, solid, a little transparent, elongate conic, light grey, color near the apex is lighter. Apex obtuse, with eight to nine whorls, sculptured with axial ribs, axial ribs near the outer lip are not prominent. Except for fine growth lines, there were some 11 to 14 axial ribs on the whorls, axial ribs exhibit a certain degree of curvature, axial ribs near the apex gradually weaken and disappear. Body whorl little swollen, has an inconspicuous lower keel, a few individuals with a strong keel at the bottom of near the top whorl, suture low. Umbilicus narrow or absent, base light grey, aperture ovate, less than half of shell in height, inner lip thickened and smooth, with an obtusely angles, greywhite, outer lip reflexed and thickened, with an obtusely angles, white or yellowish white.

Etymology. The specific name " rilliona " originates from a character “Rilliona, the Magistus of Verre” in the card game “Yu-Gi-Oh!”. We suggest the Chinese common name as " ē儿水玉Dz ".

Distribution and ecology. The habitat of this species has been destroyed due to the environmental pollution caused by the artificial modification of the lake shore and the impact of modern tourism. In recent surveys, no living individuals were found, only empty shells were discovered. This species may have become extinct. Based on the current findings of empty shells, we can speculate that this species may have been a large Pomatiopsidae species that inhabited sandy environments in the past.