Alycaeus kapayanensis Morgan, 1885b

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 : 30-31

Alycaeus kapayanensis Morgan, 1885b Figures 7O, 20, 31M

Alycaeus kapayanensis Morgan, 1885b: 403, plate 8, figure 5; Benthem Jutting 1960a: 13; Maassen 2001: 22; Tarruella and Domènech 2011: 72.

Alycaeus (Orthalycaeus) kapayensis [sic]: Möllendorff 1891: 342.

Alycaeus (Orthalycaeus) kapayanensis : Kobelt and Möllendorff 1897: 150.

Alycaeus (Alycaeus) kapayanensis : Kobelt 1902: 346; Laidlaw 1928: 35.

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

Alycaeus kapayanesis [sic]: Foon et al. 2017: 12, figure 4E.

Type locality.

Gunong Lano (= PRK 18 Gunung Lanno), Perak (4°31'31"N, 101°08'48"E).

Type material.

Syntype. Perak, Gunong Lano (= PRK 18 Gunung Lanno), Perak: MNHN IM-2000-31792/45 (1 specimen seen).

Other examined materials.

PRK 01 Gunung Tempurung, Perak: BOR/MOL 11142/11, BOR/MOL 11229/1, BOR/MOL 11385/2, BOR/MOL 11414/3. PRK 23 Gunung Rapat, Perak: BOR/MOL 241/2, BOR/MOL 6845/1, BOR/MOL 8343/4, BOR/MOL 8344/2, BOR/MOL 10031/4, BOR/MOL 10230/10, BOR/MOL 10259/4, BOR/MOL 12985/1. PRK 27 Gunung Datok, Perak: BOR/MOL 10482/4, BOR/MOL 10502/3. PRK 29 Gunung Lang, Perak: BOR/MOL 244/1, BOR/MOL 13005/13. PRK 34 Gunung Tasek, Perak: BOR/MOL 6840/5, BOR/MOL 6905/1, BOR/MOL 8405/11, BOR/MOL 8406/20, BOR/MOL 10793/52, BOR/MOL 11028/29, BOR/MOL 11065/5. PRK 42 Gunung Bercham, Perak: BOR/MOL 10629/1. PRK 47 Gunung Kanthan South, Perak: BOR/MOL 9081/38, BOR/MOL 9161/12, ZRC 1975.2.22.229/1. PRK 53 Hill KF, Perak: BOR/MOL 10671/3, BOR/MOL 10696/6. Hill 10 km NE of Sungai Siput town, Perak: BOR/MOL 246/1. Mykarst-025, Perak: BOR/MOL 9425/1, RMNH 153570/1. Mykarst-027 Gunung Kanthan North, Perak: BOR/MOL 9041/2. Limestone outcrop opposite Jalan Jalong-Lasah Chinese cemetery, NE of Sungai Siput, Perak; BOR/MOL 6876/1, BOR/MOL 8383/21, BOR/MOL 8384/1. Sungai Siput North, Perak: ZRC 1975.2.22.183-189/7, ZRC 1975.2.22.383-443/61, RMNH 153569/101, ZMA 33450/1.

Description.

Protoconch. Smooth.

Shell shape. Conical. Shell height: 4.85-5.34 mm. Shell width: 4.44-5.09 mm.

Spire. Spire height: 1.66-2.03 mm. Spire width: 2.11-2.39 mm. Number of whorls: up to 5. Spire shape: oblong conical. Whorl periphery rounded. Umbilicus open.

Whorl constriction. At about 4 ⅝ whorls posterior of protoconch.

Breathing tube. Length: 0.29-0.51 mm.

Aperture and peristome. Aperture circular, moderately expanded. Aperture height: 2.01-2.77 mm. Aperture width: 2.13-2.36 mm. Peristome single, not thickened, notched at suture. Peristome orientation 29-32° oblique with respect to the coiling axis.

Spiral lines. Distinct. Regularly spaced. Approximately 27-48 lines per 1 mm.

Radial ribs running anterior of breathing tube. Radial ribs pronounced, evenly spaced. Approximately 11-15 ribs per 1 mm.

Radial ribs running perpendicular to breathing tube. Radial ribs pronounced, evenly spaced. Approximately 10-19 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 11-23 ribs per 1 mm.

Operculum. Concave, rounded. Exterior covered with very thin calcareous layer, with indistinct appressed multilamellae. Interior covered with proteinaceous coating, smooth indistinct appressed multilamellae.

Shell colour. Whorls yellow. Peristome white.

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

Habitat and ecology.

Lives on both dry, bare rock and wet limestone walls covered with mosses or tree roots. Although it inhabits forested areas, A. kapayanensis has also been found on revegetated limestone walls at former quarries.

Distribution range.

Restricted to the karsts of Kinta Valley, Perak. Its known northern limit is at the Sungai Kerdah karst region, northeast of Sungai Siput Utara town and southern limit at Gunung Tempurung.

Differential diagnosis.

Alycaeus kapayanensis is similar to A. costacrassa sp. n. but differs consistently in having less pronounced spiral ribs and much thinner operculum. Alycaeus kapayanensis also resembles A. selangoriensis sp. n. but is consistently smaller shelled (smaller by about 0.96 mm in shell height, 1.6 mm in shell width), has less whorls, less expanded ultimate whorl and thinner operculum.

Discussion.

Historically, many Peninsular Malaysian Alycaeus with small, yellow and conical shells were lumped under A. kapayanensis out of convenience (ZRC collection lots). We systematically and empirically examined these shells from across the peninsula and concluded that A. kapayanensis is restricted to Kinta Valley. Superficially similar species elsewhere differ consistently in shell, operculum and animal characters and are thus described as new taxa: Alycaeus costacrassa sp. n., Alycaeus selangoriensis sp. n., Alycaeus ikanensis sp. n., Alycaeus alticola sp. n. and Alycaeus charasensis sp. n. In Kinta Valley, many A. kapayanensis shells have previously been labelled as " A. perakensis var. minor ", a nomen nudum ( Clements et al. 2008, ZRC collection lots). The only morphological variability in A. kapayanensis is the degree of expansion of the ultimate whorl.