Hypselostoma ophis Gojšina, Hunyadi & Páll-Gergely, 2025

Hypselostoma ophis Gojšina, Hunyadi & Páll-Gergely sp. nov.

Figs 186 J View Figure 186 , 206 View Figure 206 , 207 View Figure 207 , 223 View Figure 223

Type material.

Holotype. Thailand • 1 shell (SH: 2.1 mm; SW: 2.6 mm); Phattalung Province, Phattalung, Khao Ok Thalu , rock wall; 07°37.506'N, 100°05.330'E; 19 Feb. 2015; A. Hunyadi leg.; CUMZ 14467 View Materials GoogleMaps . Paratypes. Thailand • 5 shells (3 whole and 2 last whorls with retained apertures); same data as for holotype; coll. HA GoogleMaps .

Additional material examined.

Thailand • 1 shell (fragment, not paratype); same data as for holotype; coll. HA GoogleMaps .

Type locality.

Thailand, Phattalung Province, Phattalung, Khao Ok Thalu, rock wall; 07°37.506'N, 100°05.330'E.

Diagnosis.

A Hypselostoma species with sandpaper-like shell surface and a bluntly keeled last whorl which is detached from the penultimate and slightly ascending upwards. Five main barriers in the aperture (parietal, angular, upper palatal, lower palatal and columellar). Parietal lamella very long and wavy. Umbilicus moderately wide.

Description.

Shell shape concave-conical (due to the strongly enlarged last whorl), consisting of 4.5–5 convex whorls separated by a deep suture. Colouration dark brown, weakly glossy and opaque. Protoconch finely pitted, showing very weak spiralling pattern, consisting of ~ 1.25–1.5 whorls, coloured the same as the teleoconch. Teleoconch very finely granulated (sandpaper-like) with additional radial growth lines. Also, some irregularly spaced radial white streaks are occasionally visible. Last whorl bluntly keeled, moderately detached from the penultimate and slightly ascending upwards (~ 20 ° compared to the shell axis). In lateral view, two strong grooves are visible near the aperture, one above and one below the central keel. Peristome expanded and not reflected, slightly lighter than the rest of the shell. Aperture equipped with five strong and thick barriers (parietal, angular, upper palatal, lower palatal, and columellar) and several smaller ones. Parietal lamella very strong, wavy, and very long. Angular lamella short and sometimes separated in inner and outer part. Inner part is weaker. Both palatal plicae very strong, nearly as strong as the parietal lamella or even stronger but clearly shorter. In front of the upper palatal plica, a small swelling is present which is probably homologous with the palatal tubercle present in other genera (e. g., Bensonella , see Páll-Gergely and White 2023) Columellar lamella nearly horizontal, stronger only than the angular among the main barriers. Additionally, smaller barriers are present between the main ones. There is usually one in the interpalatal region, one basal and one between the columellar and parietal. None of these barriers reach the peristome. Surface of all barriers is very finely spiniferous medially and very finely granulated laterally. Sinulus rounded and visibly separated from the rest of the aperture. Umbilicus open and moderately wide, measuring 1 / 3 of the shell width and showing the penultimate whorl. A strong groove running from the peristome towards the umbilicus is visible. This groove is getting lost near the penultimate whorl.

Differential diagnosis.

See under H. venustum .

Measurements

(in mm, n = 4). SH = 1.76–2.1; SW 1 = 2.38–2.6; SW 2 = 1.48–1.54; AH = 0.88–0.95; AW = 0.85–0.89.

Etymology.

The specific epithet is derived from the Greek work ophis (snake) which is in special reference to the curved and long parietal lamella (which is also one of the longest in all hitherto described Hypselostoma species). To be used as a noun in apposition.

Distribution.

This species is known only from the type locality.