Hypselostoma vujici Gojšina & Páll-Gergely, 2025

Gojšina, Vukašin, Hunyadi, András, Sutcharit, Chirasak, Tongkerd, Piyoros, Auffenberg, Kurt, Grego, Jozef, Vermeulen, Jaap J., Reischütz, Alexander & Páll-Gergely, Barna, 2025, A new start? Revision of the genera Anauchen, Bensonella, Gyliotrachela and Hypselostoma (Gastropoda, Eupulmonata, Hypselostomatidae) of Southeast Asia with description of 46 new species, ZooKeys 1235, pp. 1-338 : 1-338

Hypselostoma vujici Gojšina & Páll-Gergely sp. nov.

Figs 186 S , 221 , 222 , 223

Type material.

Holotype. Thailand • 1 shell (SH: 2.47 mm; SW: 1.93 mm); Nakhon Sawan Province, 4.0 km NW of Ban Non San ; 15 ° 942 ' N, 99 ° 873 ' E; 100 m a. s. l.; 12 June 1987; F. G. Thompson leg.; UF 528941 . Paratypes. Thailand • 1 shell; same data as for holotype; CUMZ 14469 • 2 shells; same data as for holotype; UF 591364 • 8 shells (2 whole, others badly damaged, paratypes); same locality data as for holotype; locality code FGT-4325 , UF 530691 .

Additional material examined.

Thailand • 3 shells (2 juveniles, 1 last whorl with damaged aperture, not paratypes); same data as for holotype; UF 583723 .

Type locality.

Thailand, Nakhon Sawan Province, 4.0 km NW of Ban Non San; 15 ° 942 ' N, 99 ° 873 ' E; 100 m a. s. l. (provided coordinates are wrong, they cannot be understood by Google Earth).

Diagnosis.

A Hypselostoma species with 5.75–6 roughly granulated whorls and a very deep suture. Last whorl somehow canted and adnate to the penultimate near the aperture. Palatal plicae and basal plica hooked. Other barriers (angulo-parietal, columellar and infraparietal) blunt. Umbilicus narrow.

Description.

Shell high, concave-conical, shiny brown or even colourless, consisting of 5–5.5 whorls separated by a very deep suture. Protoconch almost smooth, with very weak spiralling pattern, consisting of ~ 1.5 whorls but its boundary with the teleoconch is not clearly visible due to the similar surface sculpture. Teleoconch with weak and coarse radial growth lines, which are on the last two whorls visible as white streaks, and rough granulation (sandpaper-like) but no spiral striation. Initial teleoconch whorls rounded, penultimate only very slightly less rounded. Last whorl adnate to slightly detached from the penultimate, with a very weak keel situated near the centre of the periphery. It is slightly descending near the aperture (~ 5–10 ° compared to the shell axis). Peristome dirty white, expanded but not reflected. Aperture rounded (almost as wide as high), equipped with six main barriers (angulo-parietal, upper palatal, interpalatal, lower palatal, basal and columellar) and one weak infraparietal swelling-like lamella. Angulo-parietal lamella is the strongest in the aperture, with clearly distinguishable angular and parietal part and a prominent sinuation between them. Parietal part stronger and higher than the angular, both curved towards the palatal wall. All palatal plicae hooked, pointing outside. Upper palatal and interpalatal plica positioned close together, almost equally as strong. Lower palatal plica stronger than others and situated some distance from the interpalatal. Basal plica also hooked but less clearly than the palatals, strong as the interpalatal and upper palatal but situated closer to the columellar lamella than to the lower palatal plica. Columellar lamella not hooked, long and almost horizontal. A small swelling-like infraparietal lamella is present. Angulo-parietal lamella is reaching the expanding peristome, columellar lamella almost reaching it. Surface of all apertural barriers is finely granulated. Sinulus wide, not distinctly separated from the rest of the aperture. Umbilicus always open but of variable width, measuring ~ 1 / 6 or ≤ 1 / 3 of the shell width. Umbilical groove is strong in specimens with wider and weak in specimens with narrower umbilicus.

Differential diagnosis.

This species can be separated from all other congeners by the combination of a slender shell with a larger number of whorls (usually ~ 6), roughly granulated teleoconch and hooked basal and three palatal plicae in the aperture.

Measurements

(in mm, n = 4). SH = 2.36–2.62; SW = 1.78–1.93; AH = 0.92–0.96; AW = 0.85–0.93.

Etymology.

Named after Mihailo Vujić, a prominent Serbian entomologist and a friend of the first author.

Distribution.

This species is known only from the type locality.

Remarks.

We have noticed significant intraspecific variability in this species: there were some specimens with elongated-conical, brown shell and some with more depressed spire or much lighter (sometimes even colourless) shell. Umbilicus varied from 1 / 6 to 1 / 3 of the shell width with weak or sometimes deep and strong groove inside it.

3. Hypselostoma terae group

Diagnosis. This species group is characterised by the fine, pasty surface sculpture (like floury dough). Apertural barriers are never spiniferous, never hooked and not numerous: apart from the main five barriers (angular, parietal, two palatals, and a columellar), there are usually up to two more small barriers.

Remarks. This group includes 11 species. All of them inhabit Borneo, Peninsular Malaysia, and adjacent regions of Thailand. The morphology of the species within this group agrees well with the distribution pattern.

Figures

Figure 186. Synoptic view of species belonging to Hypselostoma hungerfordianum group A H. aunglini B H. bubalus sp. nov. C H. chatnareeae D H. coriaceum sp. nov. E H. fortunatum sp. nov. F H. hungerfordianum G H. khmerianum H H. loei I H. luctans J H. ophis sp. nov. K H. piconis L H. sichang M H. srakeoense N H. surakiti O H. transitans P H. venustum Q H. vesovici sp. nov. R H. vicinum sp. nov. S H. vujici sp. nov.

Figure 221. Hypselostoma vujici Gojšina & Páll-Gergely, sp. nov., holotype (UF 528941) A – D shell E – G enlarged apertural views.

Figure 222. SEM imaging of Hypselostoma vujici Gojšina & Páll-Gergely, sp. nov., holotype (UF 528941) A protoconch surface B teleoconch surface C enlarged apertural view.

Figure 223. Distribution map of species belonging to Hypselostoma hungerfordianum group.