Bensonella cardiostoma Gojšina, Vermeulen & Páll-Gergely sp. nov.

Figs 101 A, 102, 107

Type material.

Holotype. Laos • 1 shell (SH: 1.12 mm; SW: 1.17 mm); Vientiane Province, Vang Vieng District, Nakay Village, steep forested limestone hill; 19°08.731'N, 102°22.481'E; 323 m a. s. l.; 24 Oct. 2006; A. Schuiteman leg.; locality code JJV 15174; CUMZ 14447.

Type locality.

Laos, Vientiane Province, Vang Vieng District, Nakay Village, steep forested limestone hill, 19°08.731'N, 102°22.481'E, 323 m a. s. l.

Diagnosis.

Bensonella species with obscure, weak spiral striae, asymmetric heart-shaped aperture, an angular lamella, and a palatal tubercle on the peristome and six barriers (upper palatal, lower palatal, basal, columellar, infraparietal, parietal) situated deeper inside the aperture.

Description.

Shell colourless (white), conical-ovoid with strongly widened last whorl. Whorls 3.5, nearly rounded, slightly shouldered. Protoconch consisting of 1.25 whorls, pitted, showing spiralling pattern, although no clear spiral striae are visible. Teleoconch sculpture roughly pitted. Last whorl adnate to the penultimate, very slightly ascending (~ 10 ° compared to the shell axis), thus making the apertural profile opisthocline to the shell axis. Aperture asymmetric heart-shaped, the parietal part being the shield-like extended peristome. Angular lamella and palatal tubercle situated on the peristome, both are pointed, directed towards each other. Other barriers, altogether 6, are lamella-like, elongated, low. Upper palatal plica sits behind palatal tubercle, lower palatal situated between the basal and upper palatal plica. Columella lamella situated halfway between basal and infraparietal lamella, infraparietal and parietal situated close to each other. Peristome strongly expanded, not reflected. Surface of all apertural barriers is finely granulated. Sinulus relatively narrow and clearly separated from the rest of the aperture due to the strong and closely positioned angular lamella and palatal tubercle. Umbilicus very narrow, shows only last whorl. Last quarter whorl sigmoid.

Differential diagnosis.

See under B. mitochondria sp. nov. and B. wangviangensis .

Measurements

(in mm, n = 1). SH = 1.12; SW = 1.17; AH = 0.56; AW = 0.58.

Etymology.

Named after the heart-shaped aperture.

Distribution.

This species is known only from the type locality.