Shuiyu multicostata Xiang, He, Lu & Chen, 2025

Xiang, Hong Quan, Lu, Yi Zhi, He, Yue Ming, Li, Chong Ye, Gao, Han, Lv, Ang Song & Chen, Hui, 2025, Twenty-seven new species and four new genera of Gastropoda (Animalia: Mollusca) from plateau lake Quaternary sediments in Yunnan, southwestern China, Ecologica Montenegrina 84, pp. 48-71 : 55

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.

Figures

Figure 1. Map of the ancient lakes and rivers in the Yunnan Province, south-west China, showing the sampling sites.

Figure 2. (A) paratype, Paraprososthenia bronyaae sp. nov. (B) holotype, P. bicarinata sp. nov. (C) holotype, P. jinxi sp. nov. (D) holotype, P. geguoi sp. nov. (E) holotype, P. yunjian sp. nov. (F) holotype, P. yuanqin sp. nov. (G) holotype, Shuiyu rillionaae gen. et sp. nov. (H) holotype, S. multicostata gen. et sp. nov. (I) holotype, S. shiji gen. et sp. nov. (J) holotype, S. boyuwangi gen. et sp. nov. (K) holotype, S. xuchengweii gen. et sp. nov. (L) holotype, S. phoebe gen. et sp. nov. (M) holotype, S. quanyuzhangi gen. et sp. nov. (N) holotype, S. candida gen. et sp. nov. (O) holotype, Qilinia longfeicheni gen. et sp. nov. (P) holotype, Jullienia quan sp. nov. (Q) holotype, J. chengyuangongi sp. nov. (R) holotype, Fenouilia zihaozhaoi sp. nov. (S) holotype, F. yizhou sp. nov. (T) holotype, F. pluvia sp. nov. (U) holotype, F. gaorange sp. nov. (V) holotype, Lacunopsis chengjiang sp. nov. (W) holotype, L. luliangensis sp. nov. (X) holotype, Longhai zhongxian gen. et sp. nov. (Y) holotype, Gyraulus fuxianensis sp. nov. (Z) holotype, Xingyuan jiamingzhangi gen. et sp. nov. (ZA) holotype, X. zhihehongi gen. et sp. nov. Scale bars = 10 mm.

FIGURE 4. Shells of Shuiyu rillionaae gen. et sp. nov. (A) holotype (B-C) paratype. Shells of S. multicostata gen. et sp. nov. (D) holotype (E-G) paratype. Shells of S. shiji gen. et sp. nov. (H) holotype (I-J) paratype. Shells of S. boyuwangi sp. nov. (K) holotype. Shells of S. xuchengweii gen. et sp. nov (L) holotype. Shells of S. phoebe gen. et sp. nov. (M) holotype. Shells of S. quanyuzhangi gen. et sp. nov. (N) holotype. (O-P) paratype. Shells of S. candida gen. et sp. nov. (Q) holotype. (R-S) paratype. Scale bars = 10 mm.