Alycaeus altis pirus Moellendorff , 1902

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 : 9-12

Alycaeus altis pirus Moellendorff, 1902 Figures 9, 31U

Alycaeus perakensis altispirus Möllendorff, 1902: 144-145; Maassen 2001: 23; Tarruella and Domènech 2011: 72.

Alycaeus (Alycaeus) perakensis altispirus : Zilch 1957: 147, plate 6, figure 32.

Type locality.

Kelantan.

Type material.

Lectotype . Kelantan: SMF 109738 (Seen). Paralectotypes. Kelantan: SMF 109739/3(Not seen).

Description.

Protoconch. Smooth.

Shell shape. Conical. Shell height: 6.40 mm. Shell width: 6.30 mm.

Spire. Spire height: 2.37 mm. Spire width: 2.68 mm. Number of whorls: up to 5 ½. Spire shape: oblong conical. Whorl periphery rounded. Umbilicus open.

Whorl constriction. At about 5 ¼ whorls posterior of protoconch.

Breathing tube. Length: 0.77 mm.

Aperture and peristome. Aperture circular, moderately expanded. Aperture height: 2.87 mm. Aperture width: 3.36 mm. Peristome double, not thickened, notched at suture, upper palatal section folded posteriorly into a wing-like structure. Peristome orientation 36° oblique with respect to the coiling axis.

Spiral lines. Absent.

Radial ribs running anterior of breathing tube. Radial ribs pronounced, evenly spaced. Approximately 8 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 16 ribs per 1 mm.

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

Operculum. Unknown.

Shell colour. Whorls yellow. Peristome white.

Living animal. Unknown.

Habitat and ecology.

Unknown.

Distribution range.

Unknown. Appears to be restricted to Kelantan.

Differential diagnosis.

Alycaeus altispirus is most similar to Alycaeus regalis sp. n. in having a large shell (shell height: 6.40-7.18 mm, shell width: 5.86-6.87 mm) and tall spire (spire height: 2.32-2.90 mm) but differs in the ultimate whorl being more keeled-like, upper palatal section folded posteriorly into a wing-like structure and peristome orientated oblique to the coiling axis. Unlike Alycaeus perakensis , Alycaeus altispirus is smaller (smaller by about 0.23 mm in shell height, 0.25 mm in shell width) and has a much less expanded ultimate whorl.

Discussion.

To date, this species is only known from the four type specimens collected by John Waterstradt ( Möllendorff 1902, Zilch 1957) presumably from the same locality as A. kelantanensis , on Pulai Princess Cave hill (4°47'38"N, 101°56'31"E), Kelantan (see Discussion under A. kelantanensis ; Waterstradt 1902, Liew et al. 2014). Yet no recent shells have been found on surveyed limestone hills near the locality (about 5 km from Pulai Princess Cave hill) or elsewhere in Kelantan. At the time of its description, Möllendorff (1902) considered A. altispirus a subspecies of A. perakensis but did not elaborate why. We disagree with this decision because the two taxa differ markedly from each other in shell shape especially the degree of expansion and shape of the ultimate whorl as well as their very disjunct distribution range. As such, we consider A. altispirus a species on its own.