First record of subterranean rissoidean gastropod assemblages in Southeast Asia (Mollusca, Gastropoda, Pomatiopsidae) Author Grego, Jozef text Subterranean Biology 2018 25 9 34 http://dx.doi.org/10.3897/subtbiol.25.23463 journal article http://dx.doi.org/10.3897/subtbiol.25.23463 1314-2615--9 9F789679CD744D54A7F2B0087E154571 Tricula bannaensis sp. n. Figs 43-44 Type locality. Laos; Khammouane Province, Ban Na village 20 km NNE of Thakhek, Tham Khon Don Cave, 17°33.82'N ; 104°52.30'E ,161 m a.s.l., Earthquake Dome 3 km from the south entrance, sand sediments on cave river banks (Fig. 2B). Type material. Holotype: type locality: J. Grego and M. Olsavsky leg. 11-12 February 2017 (NHMUK 20180014). Paratypes: type locality (NHMUK 20180024 - 5 specimens; HNHM 102777 - 5 specimens; OSUM 42389 - 5 specimens; Grego F0904 - 277 specimens). Measurements. Holotype: H 1.90 mm; W 1.41 mm; BW 0.75 mm; BH 1.15 mm; AH 0.92 mm; AW 0.76 mm; H/W 1.35; AH/AW 1.21; W/BW 1.88; H/BH 1.65; H/AH 2.07; W/AW 1.86. Diagnosis. The small hydrobioid shell is similar to that of T. phasoungensis sp. n., from which it differs by being more robust and with more inflated whorls, and by its larger umbilicus and larger aperture. Tricula lenahani sp. n. has a larger shell with less inflated whorls and a different shape of the aperture. Description. The whitish, translucent shell has four inflated convex whorls with a deep suture. The shell is inflated ovoid-conical with an oval aperture and slightly outward reflexed margins. Its inner side is attached to the body whorl by a marginal callus. The labral lip is typically sinuated at its lateral profile. The umbilicus is open and conspicuous. Etymology. Named after the village Ban Na, where the team enjoyed the hospitality of villagers in our base camp in the local Buddhist temple. Distribution. Only known from the type locality and nearby sites in Tham Khon Don Cave as well as in the related source of Nam Don River. Ecology. The same as Pseudoiglica pseudoiglica sp. n.