Aulacospira krobyloides Pall-Gergely & Schilthuizen

Pall-Gergely, Barna, Schilthuizen, Menno, Oerstan, Aydin & Auffenberg, Kurt, 2019, A review of Aulacospira Moellendorff, 1890 and Pseudostreptaxis Moellendorff, 1890 in the Philippines (Gastropoda, Pupilloidea, Hypselostomatidae), ZooKeys 842, pp. 67-83 : 69-71

Aulacospira krobyloides Pall-Gergely & Schilthuizen sp. n. Figures 1F, 5D

Type material.

Palawan Province, El Nido Municipality, Pinagbuyutan island, 11.121N, 119.394E, sieved from litter under limestone cliff, 17 Mar 2018, M Schilthuizen leg., TxEx-PA0001-17, RMNH.MOL.340281 (holotype, H: 2.4 mm, D: 3.5 mm).

Diagnosis.

Shell flattened and keeled, all whorls with slight subsutural furrow on the dorsal side, protoconch smooth with slight spiral striation, teleoconch roughly wrinkled and finely spirally striated; aperture with indication of a columellar tooth; aperture adnate to penultimate whorl.

Description.

Shell depressed-conical (ca. 1.5 times as wide as high) with a strong keel in the middle of body whorl, and a very slightly indicated subsutural furrow between the keel and the suture; colour off-white, but fresh specimens will probably have a darker colour; entire shell consists of 4.5 whorls; protoconch elevated, consisting of ca. 1.25 whorls, finely granulose, with some spiral striation; teleoconch finely granulose, with some fine, irregular wrinkles and fine, dense spiral striae; aperture strongly oblique to shell axis, aperture shape suboval; peristome slightly expanded from parieto-palatal junction to parieto-columellar junction, additionally slightly thickened between keel and columella, peristome slightly expanded in direction of umbilicus, partly covering it; parietal callus appears as additional, rather strong lime layer on parietal part; columellar tooth only indicated on columella, blunt; no parietal or palatal teeth present; umbilicus very narrow, shows all whorls, ca. its half is covered by expanded peristome edge.

Measurements (in mm).

H = 2.4, D = 3.5 (holotype).

Differential diagnosis.

Aulacospira krobyloides sp. n. is most similar to A. lens sp. n., which is more depressed, has a wider umbilicus, lacks spiral striation on the teleoconch, and has a parietal tooth. Aulacospira hololoma has a higher conical shell, and its aperture is free from the preceding whorl. Aulacospira triptycha is larger, flatter, has a wider umbilicus, and well-developed columellar tooth and a small palatal denticle.

Distribution.

This species is only known from the type locality on Pinagbuyutan Island (Fig. 2).

Etymology.

This new species is named for its resemblance to members of the genus Krobylos Panha & Burch, 1999.