Alycaeus kurauensis, Foon, Junn Kitt & Liew, Thor-Seng, 2017

Foon, Junn Kitt & Liew, Thor-Seng, 2017, A review of the land snail genus Alycaeus (Gastropoda, Alycaeidae) in Peninsular Malaysia, ZooKeys 692, pp. 1-81 : 34

Alycaeus kurauensis sp. n. Figures 7R, 22, 31P

Type locality.

PRK 59 Bukit Batu Kurau, Perak (4°55'45"N, 100°49'02"E).

Type material.

Holotype. PRK 59 Bukit Batu Kurau, Perak: BOR/MOL 12967. Paratypes. PRK 59 Bukit Batu Kurau, Perak: BOR/MOL 6851/10, BOR/MOL 8408/2.

Other examined materials.

PRK 59 Bukit Batu Kurau, Perak: BOR/MOL 8353/22, ZRC 1975.2.22.230-284/54.

Etymology.

Named after the type locality, Batu Kurau.

Description.

Protoconch. Smooth.

Shell shape. Conical. Shell height: 5.04-5.56 mm. Shell width: 5.34-6.06 mm

Spire. Spire height: 1.08-2.06 mm. Spire width: 2.34-2.52 mm. Number of whorls: up to 4. Spire shape: oblong conical. Whorl periphery rounded. Umbilicus open.

Whorl constriction. At about 3 ⅝ whorls posterior of protoconch.

Breathing tube. Length: 0.45-0.62 mm.

Aperture and peristome. Aperture circular, moderately expanded. Aperture height: 2.51-2.84 mm. Aperture width: 2.34-2.65 mm. Peristome double, thickened, notched at suture. Peristome orientation 35-45° oblique with respect to the coiling axis.

Spiral lines. Distinct. Regularly spaced. Approximately 24-36 lines per 1 mm.

Radial ribs running anterior of breathing tube. Radial ribs pronounced, evenly spaced. Approximately 7-16 ribs per 1 mm.

Radial ribs running perpendicular to breathing tube. Radial ribs pronounced and thicker than those anterior of breathing tube, evenly spaced. Approximately 9-16 ribs per 1 mm.

Radial ribs running posterior of breathing tube. Radial ribs absent immediately posterior of constriction. At the middle section, becoming pronounced and evenly spaced from the middle section until prior to aperture. Approximately 10-15 ribs per 1 mm.

Operculum. Concave, rounded. Exterior covered with thick calcareous layer, smooth. Interior covered with proteinaceous coating, smooth, mamillated.

Shell colour. Whorls yellow. Peristome white.

Living animal. Body cream-yellow. Head orange. Tentacles red.

Habitat and ecology.

Lives on both dry and wet limestone walls. In shady forests and cliffs on limestone hills.

Distribution range.

Restricted to Batu Kurau, Perak.

Differential diagnosis.

Alycaeus kurauensis sp. n. is similar to Alycaeus perakensis in conical shell shape and radial ribs spacing but differs in being consistently smaller (by about 1.33 mm in shell height, and by about 1.85 mm in shell width), has a less expanded ultimate whorl and peristome, a thick operculum with smooth exterior as well as body and tentacle colouration. Alycaeus kurauensis sp. n. is also similar to Alycaeus kapayanensis in size and colour but differs in having a wider ultimate whorl, thicker operculum with smooth exterior and more widely spaced radial ribs.

Discussion.

A nomen nudum " Alycaeus perakensis var. minor " was used for this subspecies in the ZRC collection. A. kurauensis sp. n. is quite consistent in all aspects of shell shape except in the ultimate whorl, which varies in the degree of expansion but never as expanded as A. perakensis .