Alycaeus jousseaumei Morgan, 1885a

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 : 27-30

Alycaeus jousseaumei Morgan, 1885a Figures 7 H–I, 19, 31F

Alycaeus jousseaumei Morgan, 1885a: 70; Morgan 1885b: 402, plate 8, figure 4; Möllendorff 1886: 312; Möllendorff 1891: 343; Tarruella and Domènech 2011: 72, figure 2B; Foon et al. 2017: 12, figure 4D.

Alycaeus (Chamalycaeus) jousseaumi [sic]: Kobelt and Möllendorff 1897: 151.

Alycaeus (Chamalycaeus) jousseaumei : Kobelt 1902: 357; Laidlaw 1928: 36; Chan 1998a: 4; Chan 1998b: 1.

Chamalycaeus jousseaumei : Benthem Jutting 1960a: 13; Berry 1963: plate 4; Maassen 2001: 24; Clements et al. 2008: 2760.

Type locality.

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

Type material.

Syntypes. Mont Lano (= PRK 18 Gunung Lanno), Perak: MNHN IM-2000-31800/1 (Not seen), MNHN IM-2000-31801/1 (Seen).

Other examined materials.

PRK 01 Gunung Tempurung, Perak: BOR/MOL 6847/1, BOR/MOL 8346/3, BOR/MOL 11136/11, BOR/MOL 11211/37, BOR/MOL 11408/10. PRK 15 Gunung Keroh, Perak: ZRC 1975.2.21.247-248/2. PRK 18 Gunung Lanno, Perak: BOR/MOL 6841/1, BOR/MOL 6916/3, BOR/MOL 8337/2, BOR/MOL 8338/2. PRK 23 Gunung Rapat, Perak: BOR/MOL 293/5, BOR/MOL 6255/1, BOR/MOL 6844/1, BOR/MOL 6846/1, BOR/MOL 6848/1, BOR/MOL 7133/6, BOR/MOL 8341/14, BOR/MOL 8342/2, BOR/MOL 8345/22, BOR/MOL 8347/25, BOR/MOL 8348/4, BOR/MOL 10046/8, BOR/MOL 10202/3, BOR/MOL 10228/9, BOR/MOL 10253/10, BOR/MOL 12963/1, BOR/MOL 12998/2, ZRC 1997.18/2. PRK 27 Gunung Datok, Perak: BOR/MOL 10412/9, BOR/MOL 10441/8, BOR/MOL 10474/30, BOR/MOL 10494/8. PRK 34 Gunung Tasek, Perak: BOR/MOL 6839/1, BOR/MOL 8336/6, BOR/MOL 10788/7, BOR/MOL 11054/1. PRK 42 Gunung Bercham, Perak: BOR/MOL 10593/4. PRK 47 Gunung Kanthan South, Perak: BOR/MOL 9101/2, ZRC 1975.2.21.2/2. PRK 53 Hill KF, Perak: BOR/MOL 10658/12, BOR/MOL 10689/13, BOR/MOL 10717/5. Mykarst-189, Perak: BOR/MOL 6842/1, BOR/MOL 8339/8. Mykarst-068, Perak: BOR/MOL 6843/1, BOR/MOL 8340/1, RMNH 153708/3. Mykarst-025, Perak: BOR/MOL 9383/1. Mykarst-027 Gunung Kanthan North, Perak: BOR/MOL 9053/3, BOR/MOL 9374/1. Mykarst-070 Kramat Pulai, Perak: ZRC 1975.2.21.238-245/8. Perak: RMNH 153477/1.

Description.

Protoconch. Smooth.

Shell shape. Flat. Shell height: 7.50-8.76 mm. Shell width: 12.42-15.03 mm.

Spire. Spire height: 1.77-2.27 mm. Spire width: 2.94-3.45 mm. Number of whorls: up to 3. Spire shape: oblong conical. Whorl periphery rounded. Umbilicus open.

Whorl constriction. At about 2 ¾ whorls posterior of protoconch.

Breathing tube. Length: 5.44-5.97 mm.

Aperture and peristome. Aperture circular, very expanded. Aperture height: 4.88-7.30 mm. Aperture width: 4.92-6.59 mm. Peristome triple. The first (most anterior) peristome is moderately expanded but not thickened. The second (outer) peristome is very expanded but not thickened. The second peristome is impressed on the thickened third (inner), non-expanded peristome. Interspace between first and second peristome wide. Interspace between second and third peristome narrow. Peristome orientation is 44-55° oblique with respect to the coiling axis.

Spiral lines. Absent.

Radial ribs running anterior of breathing tube. Radial ribs indistinct, evenly spaced. Approximately 10-18 ribs in 1 mm.

Radial ribs running perpendicular to breathing tube. Radial ribs pronounced and thick, evenly spaced. Approximately 8-15 ribs in 1 mm.

Radial ribs running posterior of breathing tube. Radial ribs pronounced, evenly spaced. Approximately 10-25 ribs per 1 mm.

Operculum. Flat, conical. Exterior calcareous, smooth but occasionally with calcareous deposits. Interior covered by proteinaceous layer, smooth.

Shell colour. First 3 whorls usually red, orange, purple or white. Ultimate whorl white. Whorl constriction generally white, occasionally red.

Living animal. Body light grey to light brown. Head pinkish-brown to dark grey. Tentacles brown.

Habitat and ecology.

Lives on limestone rock surfaces and crevices. In wet, shady forests on limestone hills.

Distribution range.

Restricted to the karsts of Kinta Valley, Perak. Its known northern limit is at Gunung Tchehel and southern limit at Gunung Tempurung.

Differential diagnosis.

Alycaeus jousseaumei is distinguished from all other Alycaeus species in Peninsular Malaysia by its very low spire, very expanded, obtuse ultimate whorl and very expanded, double peristome with wide interspace.

Discussion.

Alycaeus jousseaumei is morphologically unique and unmistakable among Peninsular Malaysian Alycaeus . Alycaeus jousseaumei has been subjected to attempts of supraspecific reclassification. Morgan (1885a) initially placed A. jousseaumei in the genus Alycaeus but Kobelt and Möllendorff ( 1897) reassigned A. jousseaumei in Chamalycaeus without any justification. The genus Chamalycaeus in Peninsular Malaysia is characterised by its small to minute shell (shell width <6.0 mm), discoid shell shape, strong radial ribs and a breathing tube of variable length ( Kobelt 1902, Maassen 2001, Egorov 2013, Foon et al. 2017). Alycaeus jousseaumei is clearly not a Chamalycaeus species. Thus, Alycaeus jousseaumei is herein reassigned back to Alycaeus . Alycaeus jousseaumei is remarkably similar to A. kapayanensis in being range-restricted to the karsts of Kinta Valley ( Morgan 1885a, 1885b, Möllendorff 1886, Möllendorff 1891, Benthem Jutting 1960a, Chan 1998a, 1998b).