Tricula reischuetzorum, Grego, Jozef, 2018

Grego, Jozef, 2018, First record of subterranean rissoidean gastropod assemblages in Southeast Asia (Mollusca, Gastropoda, Pomatiopsidae), Subterranean Biology 25, pp. 9-34 : 25

Tricula reischuetzorum sp. n. Figs 37-38

Type locality.

Laos; Khammouane Province, Cave Tham Na Li 8 km E of Thakhek on road AH131, bottom of cave river Nam Xiangliap, 17°27.20'N; 104°54.54'E.

Type material.

Holotype: type locality: J. Grego leg. 16 February 2017 (NHMUK 20180012).

Measurements.

Holotype: H 2.68 mm; W 1.29 mm; BW 0.86 mm; BH 1.61 mm; AH 0.93 mm; AW 0.79 mm; H/W 2.08; AH/AW 1.18; W/BW 1.50; H/BH 1.66; H/AH 2.88; W/AW 1.63.

Diagnosis.

The shell is similar to that of Tricula valenasi sp. n. (Tham Khon Dôn Cave), from which it differs by being smaller, less elongate and with more inflated whorls, a more closed umbilicus and a more elongated aperture situated more towards the columella. It differs significantly from T. lenahani sp. n. (Tham Khon Dôn Cave) by its overall shell shape, the position of aperture and the closed umbilicus. From T. bollingi and T. burchi it differs by general shell and aperture shape and the position of the aperture.

Description.

The milky white, narrow oval-conical shell with four convex whorls and deep suture has a blunt apex. The shell surface is smooth and shiny. The shell is narrow-conical. Aperture is ovoid elongated and its lower part slightly angled towards the columella. The aperture is attached to the body whorl by a weak furrow. The peristome margin is sharp, somewhat darker stained. The outer lip is slightly sinuated laterally. Umbilicus is closed.

Etymology.

Named after active researchers of the Balkan stygobiont gastropod fauna, Peter L. and Alexander Reischütz (Horn, Austria), who brought our attention to the Na Li cave.

Distribution.

Only known from the type locality.

Ecology.

The shells were found in the sandy sediment inside the cave Tham Na Li close to the river outlet. The about 300m long cave passage was formed by the river Nam Xiangliap under the limestone hill, and thus the cave habitat has a direct contact with surface waters.