Hypselostoma coriaceum Gojšina & Páll-Gergely, 2025

Hypselostoma coriaceum Gojšina & Páll-Gergely sp. nov.

Figs 186 D View Figure 186 , 191 View Figure 191 , 192 View Figure 192 , 223 View Figure 223

Type material.

Holotype. Malaysia • 1 shell (SH: 2.11 mm; SW 1: 3.35 mm); Langkawi Island , Tanjung Rhu ; 23 Aug. 1998; Hemmen, Wiesbaden ex. coll.; CUMZ 14464 View Materials . Paratypes. Malaysia • 30 shells; same data as for holotype; coll. PGB • 1 shell; same data as for holotype; coll. VG • 1 shell; same data as for holotype; coll. HA • 4 shells; Kedah, limestone outcrop near Tanjung Rhu, Langkawi Island ; 6°26′51.48″N, 99°48′38.89″E; 16. May 2009; M. E. Marzuki leg.; coll. PGB GoogleMaps .

Type locality.

Malaysia, Langkawi Island, Tanjung Rhu.

Diagnosis.

Shell depressed-conical, yellowish, and glossy. Last whorl bluntly keeled. Aperture detached from the penultimate whorl and slightly ascending upwards. Teleoconch finely granulated and radially striated. Spiral striation absent. Aperture equipped with five main strong barriers (parietal, upper and lower palatal, basal, and columellar) and additional smaller one of variable number.

Description.

The yellowish, glossy, and weakly translucent, depressed-conical shell is consisting of 4–4.5 whorls separated by a deep suture. The finely pitted protoconch is showing a weak spiralling pattern, consisting of ~ 1.5 whorls without a clear boundary with teleoconch. Teleoconch finely granulated, sandpaper-like (surface microsculpture similar to H. hungerfordianum ) and inconspicuously regularly radially striated. Last whorl bluntly keeled, slightly detached from the penultimate and slightly to moderately ascending upwards (~ 25–35 ° compared to the shell axis). Peristome expanded and not reflected, with sharp edges. Aperture equipped with five main barriers (parietal, angular, upper palatal, lower palatal, and columellar) and variable number of smaller ones. Angular lamella is the weakest among the main five, the rest of the main barriers are developed roughly to the same level. They are all high and straight. Parietal and angular lamellae are directed towards the palatal wall. 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). Between the angular lamella and upper palatal plica, one or two additional plicae are present. There are also usually two interpalatal plicae, two between lower palatal and columellar (including basal plica) and two between the columellar and parietal lamellae. None of these smaller barriers reach the profiles of the main ones, and none of the apertural barriers reach the peristome. Surface of all apertural barriers is very finely spiniferous medially and very finely granulated laterally. Sinulus parabolic and not very strongly separated from the rest of the aperture. Umbilicus open, initially narrow, and then abruptly widening at the last whorl, measuring ~ ¼ of the shell width and showing the penultimate whorl. A strong groove can be observed running from the peristome towards the inner side of the umbilicus.

Differential diagnosis.

This species is larger than both H. salpinx and H. saxicola and it additionally differs from them by the absence of spiral striation and a narrower umbilicus.

Measurements

. SH = 2.05–2.32; SW 1 = 3.12–3.37; SW 2 = 1.85–2.09; AH = 1.33–1.58; AW = 1.28–1.40.

Etymology.

The specific epithet is due to its “ leathery ” surface sculpture.

Distribution.

Known only from Tanjung Rhu, Langkawi Island, Malaysia.