Hypselostoma vesovici Gojšina & Páll-Gergely, 2025

Hypselostoma vesovici Gojšina & Páll-Gergely sp. nov.

Figs 186 Q View Figure 186 , 217 View Figure 217 , 218 View Figure 218 , 223 View Figure 223

Type material.

Holotype. Malaysia • 1 shell (SH: 2.18 mm; SW 1: 3.12 mm); Gua Telinga, Kuala Tahan, Taman Negara , Jerantut , Pahang; 4°22.326'N, 102°23.747'E; 69 m a. s. l.; T. Ishibe, K. Ohara, K. Okubo & J. U. Otani leg.; CUMZ 14463 View Materials GoogleMaps . Paratypes. Malaysia • 10 shells; same data as for holotype; coll. PGB GoogleMaps • 1 shell; same data as for holotype; coll. VG GoogleMaps • 1 shell; same data as for holotype; coll. HA GoogleMaps .

Type locality.

Malaysia, Gua Telinga, Kuala Tahan, Taman Negara, Jerantut, Pahang; 4°22.326'N, 102°23.747'E; 69 m a. s. l.

Diagnosis.

Shell concave-conical, with roughly granulated (sandpaper-like) surface sculpture. Last two whorls keeled below the periphery, keel especially strong on the last whorl. Last whorl detached from the penultimate, directed upwards. Aperture equipped with five main barriers and usually five smaller ones. All barriers are very broad and thick, very strongly spiniferous. Umbilicus very narrow, dot-like.

Description.

Shell concave-conical (due to the strongly enlarged last whorl), pinkish-brown in colour, corneous. It is consisting of 4.5–5 regularly increasing whorls separated by a deeply impressed suture. Protoconch finely pitted, not showing spiralling pattern, consisting of 1.25–1.5 whorls and slightly darker than the rest of the shell. Protoconch- teleoconch boundary clearly visible due to the change in shell surface sculpture. Teleoconch roughly granulated, sandpaper-like. On the last whorl near the keel, granules can in some specimens be arranged in a way to provoke a spiralling pattern although no regular spiral striae are developed. Radial lines are strong, widely and irregularly spaced, ~ 17 radial lines on the last whorl in standard view. They are more densely arranged on the initial teleoconch whorls. Protoconch and initial teleoconch whorls rounded and convex, last two whorls are keeled below the centre of the periphery. Last whorl especially strongly keeled, with a deep groove above the keel. It is also moderately detached from the penultimate near the aperture, and slightly ascending (~ 15–25 ° compared to the shell axis). Peristome whitish, strongly expanded but not reflected. Aperture large, equipped with five main barriers (parietal, angular, upper palatal, lower palatal and columellar). Angular lamella is the weakest and the shortest among the main five. All other main barriers are relatively thick and broad, almost equally developed. Parietal lamella is the longest in the aperture and surpassing the profile of the angular. Between the main barriers, several smaller ones could be observed. There are usually two interpalatal plicae, two between the lower palatal and the columellar and one knob-like infraparietal lamella. All barriers, as well as the aperture surface, are very strongly spiniferous. These spines are widely spaced (especially on the barriers) and much stronger than in other congeners. Sinulus not very distinctly separated from the rest of the aperture. Umbilicus is very narrow, dot-like, not showing previous whorls and measuring slightly> 1 / 10 of the shell width. A very shallow groove is visible running alongside the umbilicus.

Differential diagnosis.

This species is by the general shell shape similar to H. venustum from which it clearly differs by a sharply keeled last whorl below the periphery (provoking a discoid basis of the shell and a concave surface above the keel), thicker apertural barriers with very strongly spiniferous surfaces and a slightly narrower umbilicus with a much shallower groove inside it. Furthermore, the penultimate whorl in H. venustum is rounded, not keeled as in H. vesovici sp. nov. and the aperture in H. vesovici sp. nov. is much larger when compared to the rest of the shell than in H. venustum . However, the species which has the same appearance of the last whorl, and thus most similar are H. sichang and H. discobasis . In contrast to the new species, these two representatives share the different shell surface (very roughly sandpaper-like in H. sichang and coarsely spirally striated in H. discobasis ) and different arrangement of the apertural barriers (less strong and spiniferous, angular and parietal lamellae merged in H. discobasis ), as well as much wider umbilicus especially in H. discobasis . Hypselostoma vesovici sp. nov. also has clearly much larger aperture when compared to the rest of the shell than in H. sichang .

Measurements

(in mm, n = 5). SH = 2.10–2.35; SW 1 = 2.53–3.12; SW 2 = 1.49–1.77; AH = 1.10–1.23; AW = 1.05–1.25.

Etymology.

Named after Dr. Nikola Vesović, a prominent Serbian entomologist and a friend of the first author.

Distribution.

Known only from the type locality.