Alycaeus selangoriensis, 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 : 40-43

Alycaeus selangoriensis sp. n. Figures 7U, 27, 31O

Alycaeus perakensis : Laidlaw 1932: 37. [not Alycaeus perakensis Crosse, 1879a]

Alycaeus (Alycaeus) perakensis : Chan 1997: 37. [not Alycaeus perakensis Crosse, 1879a]

Alycaeus kapayanensis : Venmans 1956: 83. [not Alycaeus kapayanensis Morgan, 1885b]

Alycaeus perakensis var. minor nomen nudum, Clements et al. 2008: 2760.

Type locality.

SGR 01 Batu Caves, Selangor (3°14'17"N, 101°41'02"E).

Type material.

Holotype. SGR 01 Batu Caves, Selangor: BOR/MOL 12988. Paratypes. SGR 01 Batu Caves, Selangor: BOR/MOL 6808/1, BOR/MOL 8314/9, BOR/MOL 12989/1. SGR 02 Bukit Takun, Selangor: BOR/MOL 6810/7, BOR/MOL 8318/2.

Other examined materials.

SGR 01 Batu Caves, Selangor: BOR/MOL 268/2, BOR/MOL 6371/>1, BOR/MOL 8315/24, ZRC 1975.2.22.285-382/98, ZRC 1997.23 /5, RMNH 153568/16, ZMA 33474/1. SGR 02 Bukit Takun, Selangor: BOR/MOL 6627/14, BOR/MOL 8317/6, ZRC 1975.2.22.190-228/39, ZRC 1975.2.24.403-439/37, ZRC 1997.22/5.

Etymology.

Named after Selangor, the state that the type locality of this species is part of.

Description.

Protoconch. Smooth.

Shell shape. Conical. Shell height: 5.07-5.44 mm. Shell width: 5.06-5.88 mm.

Spire. Spire height: 1.81-2.00 mm. Spire width: 2.35-2.50 mm. Number of whorls: up to 5 ¼. Spire shape: oblong conical. Whorl periphery rounded. Umbilicus open.

Whorl constriction. At about 5 whorls posterior of protoconch.

Breathing tube. Length: 0.52-0.71 mm.

Aperture and peristome. Aperture circular, expanded. Aperture height: 2.68-2.37 mm. Aperture width: 2.33-2.61 mm. Peristome double, not thickened, upper palatal section folded posteriorly into a wing-like structure, notched at suture. Peristome orientation 35-40° oblique with respect to the coiling axis.

Spiral lines. Distinct. Regularly spaced. Approximately 20-33 lines per 1 mm.

Radial ribs running anterior of breathing tube. Radial ribs pronounced, evenly spaced. Approximately 7-20 ribs per 1 mm.

Radial ribs running perpendicular to breathing tube. Radial ribs pronounced, white and thicker than those anterior of breathing tube, evenly spaced. Approximately 11-21 ribs per 1 mm.

Radial ribs running posterior of breathing tube. Radial ribs absent immediately posterior of constriction, becoming pronounced and evenly spaced at the middle until prior to aperture. Approximately 9-14 ribs per 1 mm.

Operculum. Concave, rounded. Exterior covered with thick but flaky calcareous layer, surface finely granulated. Interior proteinaceous layered, smooth, with indistinct mamilla.

Shell colour. Whorls yellow. Peristome white.

Living animal. Body cream-white. Head pinkish-brown. Tentacles reddish-brown.

Habitat and ecology.

Lives on wet limestone walls covered with mosses, in forested areas. It can also be found in areas with substantial human disturbance such as on the limestone walls of the temple at Batu Caves.

Distribution.

Restricted to Batu Caves and Bukit Takun, Selangor.

Differential diagnosis.

Alycaeus selangoriensis sp. n. is most similar to A. kapayanensis but differs in having a consistently larger shell (larger by about 0.96 mm in shell height, 1.6 mm in shell width), more expanded ultimate whorl and thicker operculum with calcareous exterior. The upper palatal section of the peristome in A. selangoriensis sp. n. is always folded posteriorly and downwards, creating a wing-like extension prior to the notch at the suture, a feature not present in the simple circular expanded peristome of A. kapayanensis . Alycaeus selangoriensis sp. n. resembles A. perakensis in having a moderately expanded ultimate whorl but differs in being smaller shelled (smaller by about 1.37 mm in shell height, 2.08 mm in shell width).

Discussion.

Historically, Alycaeus selangoriensis sp. n. shells have been assigned to superficially similar congeners A. perakensis and A. kapayanensis ( Laidlaw 1932, Venmans 1956, Chan 1997, ZRC and RMNH collection lots). Alycaeus selangoriensis sp. n. has also been labelled as " Alycaeus kapayanensis var. minor ", a nomen nudum ( Clements et al. 2008, ZRC collection lots). Alycaeus selangoriensis sp. n. is morphologically consistent in having a very expanded ultimate whorl but varies in spire height. Venmans (1956) described and found that the radula and jaw of A. selangoriensis sp. n. differ substantially from A. thieroti and A. conformis .