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

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

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

Holotype.

NCUMB 25015 , Tongbohe River [铜钵河], Qingning Town [青宁镇], Tongchuan District [通川区], Dazhou City [达州市], Sichuan Province, China, 31.50518°N, 107.40832°E, leg. Zhong-Guang Chen & Yan-Shu Guo, June 2025. GoogleMaps

Paratypes:

n = 19. NCUMB 25016 –24, other information same as holotype; NCUMB 25025 –34, leg. Yu-Chen Wang, June 2025, other information same.

Diagnosis.

Same as the genus.

Description.

Shell conical, dextral, small to medium-sized ( SH 22.2–32.5 mm), relatively thick, solid, opaque, glossy, with 6.0–7.0 whorls in adults. Whorls inflated. Suture rather deep. Early teleoconch with dense spiral lines invisible to the naked eye, apex blunt and low. Teleoconch almost smooth, without keels or hairs, with dense growth lines. Aperture waved, ovate, oblique, more than half of shell in height. Inner shell surface 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 to brown, apex region darker.

Operculum much smaller than aperture ( OH / AH = 0.55–0.61), corneous, ovate, thin, reddish-brown, exterior surface of operculum rough, inner surface smooth.

Radular central tooth with a relatively sharp central denticle and four small and sharp cusps on both sides; lateral tooth with a medium and blunt central denticle and three small and sharp cusps on both sides; inner marginal tooth with a relatively small and blunt central denticle and four small and sharp cusps on both sides; outer marginal tooth with 18–19 long and very sharp cusps.

Measurements.

Holotype: SH 29.4 mm, SW 22.8 mm; AH 18.2 mm, AW 13.3 mm; OH 10.6, OW 7.3; SW / SH = 0.78, AW / AH = 0.73, AH / SH = 0.62, OH / AH = 0.58. Paratypes: SH 22.2–32.5 mm, SW 18.5–23.7 mm; AH 15.4–19.2 mm, AW 11.1–14.2 mm; OH 8.4–11.6, OW 6.3–7.3; SW / SH = 0.75–0.83, AW / AH = 0.67–0.75, AH / SH = 0.56–0.69, OH / AH = 0.55–0.61.

Vernacular name.

达州巴田螺 (dá zhōu bā tián luó).

Distribution and ecology.

Same as the genus.

Remarks.

The population size of this species seems to have experienced a serious decline. Tens of thousands of empty shells were found by the river, but very few living animals were found. Living specimens are generally smaller and thinner than the empty shells (Fig. 9 View Figure 9 ).