Bapaludina Z.-G. Chen & Y.-S. Guo, 2025

Genus Bapaludina Z.-G. Chen & Y.-S. Guo gen. nov.

Figs 3 C View Figure 3 , 4 E, F View Figure 4 , 5 B View Figure 5 , 9 View Figure 9

Type species.

Bapaludina dazhouensis Z.-G. Chen & Y.-S. Guo , sp. nov.

Diagnosis.

Shell small to medium-sized ( SH 22.2–32.5 mm), relatively thick and solid; apex blunt. Whorls inflated. Suture rather deep. Teleoconch almost smooth, without 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 thin, much smaller than aperture ( OH / AH = 0.55–0.61), exterior surface of operculum rough, inner surface of operculum smooth. Lateral and inner marginal teeth with a small to medium, blunt central denticle and some small and sharp cusps on both sides.

Description.

See the species description.

Etymology.

The genus name is made from “ Ba, ” the abbreviation for eastern Sichuan and Chongqing, and “ paludina ” for river snails.

Vernacular name.

巴田螺属 (bā tián luó shǔ).

Distribution and ecology.

Known from the tributaries of the upper Qujiang River (a tributary of Jialingjiang River) in the northern Dazhou (Fig. 6 View Figure 6 ). Living in the pebble-bottom sections of the cold and flowing tributaries with seasonal floods (Fig. 6 View Figure 6 ). No living animals were found in the main streams or the muddy or still-water sections of the tributaries.

Remarks.

Bapaludina gen. nov. is the sister group of Sinotaia but differs by the different early teleoconch (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). The p-distances of COI sequences between Bapaludina gen. nov. and Sinotaia are 6.7 %, which is larger than that between the new genus and Torotaia Haas, 1939 (5.0 %), or Anularya Zhang & Chen, 2015 (5.2 %).