Bensonella nitens Gojšina & Páll-Gergely, 2025

Bensonella nitens Gojšina & Páll-Gergely sp. nov.

Figs 39 Q View Figure 39 , 74 View Figure 74 , 75 View Figure 75 , 100 View Figure 100

Type material.

Holotype. Thailand • 1 shell (SH: 1.91 mm; SW: 1.77 mm); Phrae Province, 11 km W of Phrae, on Road 1023 limestone knoll , leaf litter; 18°10′41″N, 100°4′14″E; 290 m a. s. l.; 16. May 1988; F. G. Thompson leg.; locality code FGT-4447 , UF 346975 GoogleMaps . Paratypes. Thailand • 2 shells; same data as for holotype; CUMZ 14440 View Materials GoogleMaps • 45 shells; same data as for holotype; UF 591334 GoogleMaps .

Additional material examined.

Thailand • 4 shells (juveniles, not paratypes); same data as for holotype; UF 583730 GoogleMaps .

Type locality.

Thailand, Phrae Province, 11 km W of Phrae, on Road 1023 limestone knoll, leaf litter; 18°10′41″N, 100°4′14″E; 290 m a. s. l.

Diagnosis.

Shell concave-conical, glossy, last whorl strongly enlarged. Teleoconch spirally striated. Last whorl adnate to the penultimate. Aperture equipped with numerous barriers, angular and columellar lamellae reaching the peristome. Umbilicus moderately wide.

Description.

Shell concave-conical, brownish, consisting of 5–5.5 convex, rounded whorls separated by a deep suture. Last whorl much wider than all preceding ones, resulting in a concave-conical shell shape. Protoconch finely spirally striated initially, more prominently terminally. Its boundary with the teleoconch is not clearly visible due to the similar surface sculpture. Fine spiral striae present across the whole shell surface but quite difficult to observe on initial teleoconch whorls without SEM imaging. They are most clearly visible on the last whorl but still very fine. Spacing between the two spiral striae approximately measures the width of one or two striae. Radial growth lines extremely fine, irregularly spaced and not numerous, most clearly visible on the last and the penultimate whorls. Last whorl rounded, slightly descending (~ 10 ° compared to the shell axis), and adnate to the penultimate near the aperture. Peristome brownish, expanded but not reflected. On the parietal side of the aperture, the peristome leans on the penultimate whorl forming a thin parietal callus. Aperture equipped with numerous barriers (angular, parietal, upper palatal, two interpalatals, lower palatal, palatal tubercle, basal, columellar, and infraparietal). Parietal lamella is the strongest in the aperture, blade like and relatively high. Angular lamella discontinuous, consisting of weaker outer part (which is reaching the expanding peristome) and stronger (higher) inner part. Palatal plicae almost all equidistant. Upper palatal and first interpalatal equally strong, higher in their inner than in outer parts (but upper palatal can be weaker than the interpalatal). There is a strong, white palatal tubercle sitting on the palatal lip of the aperture, in front and between the upper palatal and interpalatal plica. Lower interpalatal plica is the weakest among them all. Lower palatal plica is the strongest among all the palatals. Sometimes, a very weak infrapalatal plica is also present and situated between the lower palatal and basal. All palatal plicae continue as slender projections towards the peristome. Basal plica small and usually the weakest in the aperture. Columellar lamella strong and oblique, leaned towards the parietal lamella. Infraparietal lamella slightly stronger than the basal plica. Surface of all apertural barriers is finely granulated. Sinulus parabolic due to the position of the angular lamella and the palatal tubercle. Umbilicus moderately wide, measuring ~ 1 / 5 of the shell width.

Differential diagnosis.

This species is similar to Bensonella microdentata sp. nov., but the barriers are more numerous and not spiniferous, the umbilicus is wider and the last whorl is more enlarged. Bensonella nitens sp. nov. is smaller, glossier and has a weaker surface sculpture than B. multidentata sp. nov. The apertural barrier arrangement is strikingly similar in these two species but B. multidentata sp. nov. has stronger barriers and palatal plicae without slender projections towards the peristome. These projections are always present in B. nitens sp. nov. See also under B. sericata sp. nov. and B. tamphathai .

Measurements

(in mm, n = 5). SH = 1.91–2.00; SW = 1.57–1.87; AH = 0.86–0.96; AW = 0.86–0.94.

Etymology.

The specific epithet refers to the shiny shell surface.

Distribution.

This species is known only from the type locality.