Ganesella halabalah Sutcharit & Panha

Sutcharit, Chirasak, Backeljau, Thierry & Panha, Somsak, 2019, Re-description of the type species of the genera Ganesella Blanford, 1863 and Globotrochus Haas, 1935; with description of a new Ganesella species from Thailand (Eupulmonata, Camaenidae), ZooKeys 870, pp. 51-76 : 51

Ganesella halabalah Sutcharit & Panha sp. nov. Figures 4 A–C , 8

Type material.

Holotype CUMZ 2608 ( Fig. 4A , height 22.6 mm, width 23.3 mm, 5¾ whorls), paratypes CUMZ 2599 (3 shells; Fig. 4B , height 22.0 mm, width 22.1 mm) from the type locality. Paratype ZMB 53120 (1 shell; Fig. 4C ) ex. Waterstradt coll. from Gunung Tahan, Kelantan, Malaysia.

Type locality.

Sirindhorn Waterfall, Hala-Bala Wildlife Sanctuary, Waeng District, Narathivat Province, Thailand.

Diagnosis.

The dextral, large, trocoid shell with pale green to yellow colour, obtuse apex and apertural lip with prominent beak-like deflection.

Description.

Shell. Shell medium-sized (height 23.6 mm, width 25.1 mm), thin, dextral and trochoid. Apex obtuse; embryonic shell smooth and black. Whorls 5-6, increasing regularly, smooth; suture wide and shallow; shell surface with thin growth lines. Last whorl large, with well-developed peripheral keel and blunt at lower periphery. Shell colour pale green or yellow to monochrome creamy; earlier whorls paler; with or without brown spiral band on peripheral keel and lower periphery. Periostracum thin corneous, brownish and translucent. Aperture relatively large, semi-ovate; parietal callus transparent; columella wide and whitish. Apertural lip expanded, whitish, and angled with prominent beak-like deflection at peripheral keel. Umbilicus rimate and partially obscured by lower apertural lip.

Etymology.

The specific name is derived from the type locality Hala-Bala Wildlife Sanctuary, Narathivat, Thailand.

Distribution.

This new species is currently known from the type locality (in Narathivat, Thailand) and Gunung Tahan, Kelantan, Malaysia, which is about 150 km south of the type locality. The latter shell ( Fig. 4C ) was collected in 1901 in a tropical rain forest. This shell is in all aspects identical to the unique name-bearing type.

Remarks.

Even though Ganesella halabalah sp. nov. is described from empty shells, its unique features mean that it cannot be confused with any other camaenid species from the area. Yet, with its trochoid shell and its prominent, beak-like apertural rostrum, G. halabalah sp. nov. does resemble a Papuininae phenotype. However, the geographic distribution of the Papuininae is largely restricted to New Guinea, Australia and Melanesia ( Schileyko 2003), though excluding the Greater Sunda Islands and Indochina. Given that the Malay Peninsula is a remote area for land snail dispersal between Australasia and Indochina ( Hausdorf 2000), further anatomical and molecular evidence is needed to assess an eventual relationship with Papuininae.

This new species clearly differs from all Ganesella and other land snail species known in Indochina. The most similar species is Ganesella perakensis (Crosse, 1879) from Malaysia, which has a much smaller (average shell height <10 mm), thin shell, and a simple apertural lip ( Fig. 4D ). Ganesella halabalah sp. nov. has a larger shell (average shell height> 20 mm), an obtuse apex and an aperture lip with a typical, prominent beak-like deflection.

The new species also differs from all Kenyirus Clements & Tan, 2012 species from Malaysia by having a conical spire, yellowish shell and narrower umbilicus. While K. sodhii Clements & Tan, 2012 has a depressed spire, long spout-like apertural rostrum on the peripheral keel, and 3-4 brownish spiral bands on the last whorl. In comparison K. sheema Foon et al., 2015 has subglobose shell, an angular last whorl, and with two brownish spiral bands below the periphery; while K. balingensis Tan et al., 2017 has a smaller and brownish shell.

Figures

Figure 4. A-C Ganesella halabalah sp. nov. A holotype CUMZ 2608 B paratype CUMZ 2599 from the type locality and C paratype ZMB 53120 from Kelantan, Malaysia D Ganesella perakensis, syntype MNHN-IM- 2000 - 1964. E-G Globotrochus onestera E lectotype MNHN-IM- 2000 - 32456 F holotype of " simonei Thach & Huber, 2017 " MNHN-IM- 2000 - 33206 and G specimen from Vietnam CUMZ 5218 H Globotrochus mellea, holotype RBINS / MT / 525051.

Figure 8. Geographic distribution of Ganesella spp. and Globotrochus spp.