Cristaria wangyucheni Z. - G. Chen & Y. - T. Dai 2026, sp. nov.

Cristaria wangyucheni Z. - G. Chen & Y. - T. Dai sp. nov. Fig. 2 Type materials. Holotype. • JXAU 2503001 (collected alive, soft part stored in ethanol separately), Tongbo 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. Yu-Chen Wang, March 2025. Paratypes: n = 8, • JXAU 2503002 (collected alive, soft parts stored in ethanol separately), • JXAU 2503003 –006 (empty shells), other information same as holotype; • JXAU 2503007 –009 (empty shells), leg. Zhong-Guang Chen & Yan-Shu Guo, June 2025, other information same as holotype. Diagnosis. Shell elongated triangle to irregular rectangle, inflated, very thin, fragile, with a maximum length of about 100 mm. Postdorsal wing small and low. Description. Shell medium size, thin, inflated, elongated, glossy, opaque. Post-dorsal wing small and low. Anterior small, rounded, and short; posterior expanded, wide, and long. Dorsal margin slightly curved downwards and truncated in behind; ventral margin weakly curved or retuse. Umbo inflated, slightly higher the hinge line, located at 1 / 4 of the dorsal margin, with concentric square carving. Periostracum yellowish green to brown with thin growth lines with a shallow sulcus in the middle of the dorsal margin. Growth lines arranged in irregular concentric circles. Hinge short. Ligament short and strong. Beak cavities shallow, open. Mantle attachment scars on the pallial line indistinct. Anterior adductor muscle scars oval, shallow, smooth; posterior adductor muscle scars oval, smooth. Pseudocardinal teeth completely degenerates and disappears. Lateral teeth of both valves short and thin. Nacre light white. Mantle light brown. aperture margins black, papillae of the excurrent aperture highly vestigial, papillae of the incurrent aperture weak. Gills light brown, inner gills slightly longer and wider than outer gills. Labial palpsrown, irregular triangle, distally pointed. Visceral mass grayish white. Foot grayish white. Measurements. Holotype: shell length 95.1 mm, height 54.9 mm, width 42.0 mm. Paratypes: shell length 62.5–105.9 mm, height 41.8–61.9 mm, width 25.0– 42.8 mm (Table 3). Etymology. The species is named after Yu-Chen Wang, who first discovered it. Vernacular name. 王氏冠蚌 (pīnyīn: wáng shì guàn bàng). Distribution and ecology. Known from the type locality only (Fig. 1). Living in the pebble-bottom sections of the cold and flowing tributaries with seasonal floods, along with Pseudocuneopsis sp., Nodularia sp., and Ptychorhynchus sp. This species is considered to have a small population, as evidenced by multiple surveys that revealed a narrow distribution and a scarcity of live specimens.