Bensonella sericata Gojšina & Páll-Gergely, 2025

Bensonella sericata Gojšina & Páll-Gergely sp. nov.

Figs 39 Z View Figure 39 , 87 View Figure 87 , 88 View Figure 88 , 100 View Figure 100

Type material.

Holotype. Thailand • 1 shell (SH: 2.38 mm, SW: 1.69 mm); Chiang Rai Province, limestone knoll, Ban Mae Song Nai , 4.0 km N, 6.0 km NW Mae Chan, limestone domes, shaded ledges; 20°11′37″N, 99°33′6″E; 520 m a. s. l.; 10. May 1988; F. G. Thompson leg.; locality code FGT-4425 ; UF 380270 GoogleMaps . Paratypes. Thailand • 4 shells; same data as for holotype; UF 591360 GoogleMaps .

Additional material examined.

Thailand • 5 shells (juveniles, not paratypes); same data as for holotype; UF 591368 GoogleMaps .

Type locality.

Thailand, Chiang Rai Province, limestone knoll, Ban Mae Song Nai, 4.0 km N, 6.0 km NW Mae Chan, limestone domes, shaded ledges; 20°11′37″N, 99°33′6″E; 520 m a. s. l.

Diagnosis.

A Bensonella species with conical to conical-ovoid shell, very dense spiral striation, and a small number of apertural barriers, only four of which are strong (parietal, upper palatal, lower palatal and columellar).

Description.

Shell brown, conical to conical-ovoid, whorls 4.5–5, convex, regularly increasing. Protoconch consisting of ~ 1.5 whorls, its sculpture consists of ~ 10 roughly equidistant spiral striae. Teleoconch finely, very densely spirally striated, and ornamented with a few, inconspicuous radial growth lines. Last whorl adnate to the penultimate and slightly descending near the aperture (~ 15 ° compared to the shell axis) making the aperture profile prosocline to the shell axis. Peristome slightly expanded, not reflected. A blunt, weak, knob-like palatal tubercle sits anterior and slightly below the upper palatal plica on the peristome edge. Parietal lamella is the strongest in the aperture and slightly leaned towards the palatal wall. Angular lamella weak, its outer part reduced, inner part sits deep in the aperture. Upper palatal plica in form of a very weak swelling, situated slightly above the palatal tubercle. Interpalatal plica strong, located slightly below the palatal tubercle. Lower palatal plica nearly as strong as the parietal, stronger than the interpalatal. There can be two additional swellings: one between the upper and interpalatal and one between the interpalatal and lower palatal. Basal plica absent. Columellar lamella strong and slightly oblique. Infraparietal lamella in form of indistinct swelling located close to the parietal lamella. Surface of all apertural barriers is smooth. Sinulus wide and relatively well separated from the rest of the aperture due to the strong parietal lamella. Umbilicus moderately wide, measuring 1 / 5 of shell width.

Differential diagnosis.

This species differs from B. multidentata sp. nov. by the less numerous apertural barriers (including the lack of the basal plica) and not concave-conical shell. The shell in B. multidentata sp. nov. is also more pointed. Bensonella nitens sp. nov. is glossier due to the very coarse spiral striae (very dense in B. sericata sp. nov.), concave conical and has slender and sharp projections proximally and distally from the palatal plicae. See also under B. tamphathai .

Measurements

(in mm, n = 4). SH = 2.26–2.39; SW = 1.69–1.73; AH = 0.94–1.01; AW = 0.87–0.94.

Etymology.

The specific epithet refers to the silky surface of the shell (as if “ covered in silk ”).

Distribution.

This species is known only from the type locality.

Remarks.

Coordinates of the sample point in Myanmar just next to the Thai border.