Shupaludina Z. - G. Chen, Y. - T. Dai, H. Chen & X. - P. Wu 2025, gen. nov.

GenusShupaludinaZ.-G. Chen, Y.-T. Dai, H. Chen & X.-P. Wu gen. nov. Figs 2, 3 A, B, 4 A – D, 5 A, 8 Type species. Paludina magnaciana Heude, 1889. Diagnosis. Shell small to medium-sized (SH 20.3–40.4 mm), relatively thick and solid; apex blunt. Whorls inflated. Suture rather deep. Teleoconch with several weak and indistinct keels. Inner lip of the aperture is folded and tightly overlapping on the columellar margin, completely covering the umbilicus and forming with growth a crescent-shaped fortification, even in juvenile specimens. Operculum rather thick, much smaller than aperture (OH / AH = 0.72–0.83), exterior surface of operculum rough, inner surface of operculum with a smooth outer ring and a rough inner ring, the nuclear region with shiny grains. Lateral and inner marginal teeth with a large, broad, and blunt central denticle and some small and sharp cusps on both sides. Description. Shell conical, dextral, small to medium-sized (SH 20.3–40.4 mm), relatively thick, solid, opaque, glossy, with 5.5–7.0 whorls in adults. Whorls inflated. Suture rather deep. Early teleoconch almost smooth or with spiral lines invisible to the naked eye, apex blunt and low. Teleoconch with several weaker and indistinct keels, without hairs, with dense growth lines. Aperture waved, ovate, oblique, more than half of shell in height. Inner shell surface orange to white. Outer lip black and thickened, inner lip of the aperture is folded and tightly overlapping on the columellar margin, completely covering the umbilicus and forming with growth a crescent-shaped fortification, even in juvenile specimens. Shell multicolored, teleoconch yellowish-green, brown, or reddish-brown, apex region darker. Operculum much smaller than aperture (OH / AH = 0.72–0.83), corneous, ovate, rather thick, dark brown, exterior surface of operculum rough, inner surface of operculum with a smooth outer ring and a rough inner ring, the nuclear region with shiny grains. Radular central tooth with a relatively sharp central denticle and six small and sharp cusps on both sides; lateral tooth with a large, broad, and blunt central denticle and four to five small and sharp cusps on both sides; inner marginal tooth with a large, broad, and blunt central denticle and four to five small and sharp cusps on both sides; outer marginal tooth with 15–22 long and very sharp cusps. Etymology. The genus name is made from the Shu abbreviation for Sichuan and paludina for river snails. Vernacular name. 蜀田螺属 (shǔ tián luó shǔ). Distribution and ecology. Known from the tributaries of the Minjiang River and Tuojiang River in northwestern Chengdu and the Yongninghe River in southern Luzhou (Fig. 6). Maybe distributed in the Qujiang River from eastern Sichuan to northern Chongqing. The genus may have a wider potential distribution. The first author identified similar specimens during fish surveys in the Qingyijiang River at Yaan (Fig. 6) from 2017 to 2020 but did not preserve the specimens. Living in the pebble-bottom sections of the cold and flowing tributaries with seasonal floods in sympatry with Hua spp., Lithoglyphopsis spp., and Tricula spp. (Fig. 6). No living animals were found in the main streams or the muddy or still-water sections of the tributaries. Remarks. The major diagnostic characters of all six genera of Bellamyinae distributed in the upper Changjiang River Basin were shown in Fig. 5 and Table 2. In terms of morphology, Shupaludina gen. nov. is most similar to Bapaludina gen. nov. by the similar shell shape, the outward folding and tightly overlapping inner lip, and the small operculum. It can be distinguished from Bapaludina gen. nov. by the presence of keels on the teleoconch (vs. absence), the larger and thicker operculum (OH / AH = 0.72–0.83 vs. 0.55–0.61), the larger crescent-shaped fortification, and the larger, broader, and blunter central denticle of the lateral and inner marginal teeth. Shupaludina gen. nov. is somewhat similar to Sinotaia by the similar shell size and shape (Fig. 5), but differs by the different early teleoconch (almost smooth or with spiral lines vs. smooth but covered with hairs, although these are lost as specimens mature), the larger aperture (AH / SH> 1 / 2 vs. <1 / 2), the outward folding and tightly overlapping inner lip (vs. thin and simple), and the operculum much smaller than aperture (vs. almost same size as aperture). In terms of molecular phylogeny, Shupaludina gen. nov. is the sister group of Dalipaludina but differs by the smaller shell, the blunt apex (vs. pointed), the larger aperture (AH / SH> 1 / 2 vs. <1 / 2), the outward folding and tightly overlapping inner lip (vs. thin and simple), and the operculum much smaller than aperture (vs. almost same size as aperture). Shupaludina gen. nov. has a special overlapping inner lip and small operculum, which is similar to Bakyietaia Zhang, Yen & von Rintelen, 2025. The two genera can be distinguished by the different apex (blunt vs. pointed), the different early teleoconch (rounded vs. keeled), the different keels on the teleoconch (very weak vs. strong), and the larger aperture (AH / SH> 1 / 2 vs. <1 / 2 in most species). Molecular phylogeny and isolated distributions also supported the difference between them. Shupaludina gen. nov. is distributed in the Changjiang River, while Bakyietaia is distributed in the Pearl River, the Red River, the Hainan insular rivers, and the mainland coastal rivers in southern China (Zhang et al. 2025). Yen (1938) recorded Bakyietaia polyzonata (Frauenfeld, 1862) in Sichuan. However, the specimens presented in the article appear to be more akin to Sinotaia. Bakyietaia polyzonata is endemic to the upper Pearl River in southwestern Guangxi and northern Vietnam (Zhang et al. 2025). Bakyietaia wilhelmi (Yen, 1939) recorded in Chengdu were also artificially introduced (Zhang et al. 2025).