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.