Bensonella alycaeus Gojšina, Hunyadi & Páll-Gergely, 2025

Bensonella alycaeus Gojšina, Hunyadi & Páll-Gergely sp. nov.

Figs 39 A View Figure 39 , 40 View Figure 40 , 41 View Figure 41 , 100 View Figure 100

Type material.

Holotype. Thailand • 1 shell (SH: 1.6 mm, SW: 1.3 mm); Chiang Rai Province, Doi Thung ; 20°20.533'N, 99°50.350'E; 1320 m a. s. l.; 08 May 1988; F. G. Thompson leg. UF 347144 GoogleMaps . Paratypes. Thailand • 1 shell; same data as for holotype; CUMZ 14433 View Materials GoogleMaps • 7 shells; same data as for holotype; UF 591340 GoogleMaps • 1 shell; Chiang Rai Province, Doi Tung, 50 meters before Wat Phra That Doi Tung , vicinity of the parking lot; 20°19.563'N, 99°49.990'E; 1350 m a. s. l.; 12 Feb. 2015; A. Hunyadi leg.; coll. HA GoogleMaps .

Additional material examined.

Thailand • 1 shell (juvenile, not paratype); same data as for holotype; UF 583721 GoogleMaps .

Type locality.

Thailand, Chiang Rai Province, Doi Thung; 20°20.533'N, 99°50.350'E; 1320 m a. s. l.

Diagnosis.

Bensonella species with a triangular-conical shell and strongly radially ribbed last whorl, especially near the aperture. Palatal plicae very strong. Umbilicus very narrow and elongated, dot-like.

Description.

Shell triangular, conical-ovoid, brown, consisting of 4.5–5 convex, rounded whorls separated by a moderately deep suture. Protoconch spirally striated (~ 12–15 spiral striae). The protoconch is initially light in colour and then regularly darkening towards the teleoconch. Teleoconch surface very finely spirally striated, striae much weaker than on the protoconch. On the penultimate whorl, relatively coarse, weak, radial growth lines are visible. They become more densely arranged and more prominent on the last whorl and especially near the aperture where they are rib-like (important for species identification!). They are crossed by very delicate and widely spaced spiral striae. Last whorl rounded and adnate to the penultimate. It is slightly ascending near the aperture (~ 20 ° compared to the shell axis), making the aperture profile weakly opisthocline. Peristome lighter than the rest of the shell, not much expanded and not reflected. There is a slight thickening behind the peristome in form of a cervical crest. Aperture equipped with 10–12 barriers. Parietal lamella is the strongest in the aperture, long and curved, sinuated in its middle part. Angular lamella long, thin, and continuous, reaching the peristome. There are four main palatal plicae (upper palatal, two interpalatals, and a lower palatal) and usually one smaller suprapalatal plica. Upper palatal plica strong, highest in its middle part and getting lower towards the peristome. Interpalatal plicae similar to each other and the upper palatal. Lower palatal plica is the strongest. There is a strong palatal tubercle sitting on the palatal lip of the peristome, sometimes of almost rectangular shape. Peristome is distinctly sinuated behind this tubercle. Below the palatal tubercle, there are usually one or two more tubercle-like swellings which are of unknown homology. Basal plica very weak and short. Columellar lamella almost horizontal and slightly weaker than upper and lower palatal plicae. Infraparietal lamella similar to the basal plica. Surface of all apertural barriers is finely granulated. Sinulus small, narrow, and distinctly separated from the rest of the aperture. Umbilicus very narrow, dot like and elongated.

Differential diagnosis.

This species is different from other congeners by the strong, rib-like radial growth lines, especially on the last whorl near the aperture and very strong palatal plicae.

Measurements

(in mm, n = 5). SH = 1.55–1.78; SW = 1.3–1.57; AH = 0.65–0.80; AW = 0.65–0.70.

Etymology.

The specific epithet refers to the cyclophoroid subfamily Alycaeinae W. T. Blanford, 1864 due to the changing rib density on the last whorl. To be used as a noun in apposition.

Distribution.

This species is known only from the type locality.