Haploptychius bombax (Benson, 1859)

Sian Man, Nem, Siriboon, Thanit, Lin, Aung, Sutcharit, Chirasak & Panha, Somsak, 2022, Revision of the carnivorous land snail family Streptaxidae (Stylommatophora, Achatinina) in Myanmar, with description of four new species, ZooKeys 1110, pp. 39-102 : 39

Haploptychius bombax (Benson, 1859)

Fig. 9

Helix bombax Benson, 1859b: 186. Type locality: Moulmein, necnon and Phie Than in provincia Tenasserim [Mawlamyine, Mon State and Payathonzu, Kayin State, Myanmar]. Pfeiffer 1868: 151. Hanley and Theobald 1870: 15, pl. 31, figs 1, 4.

Streptaxis bombax - Stoliczka 1871: 167. Hanley and Theobald 1870: 63, pl. 156, fig. 9. Nevill 1878: 3. Blanford and Godwin-Austen 1908: 4, 5.

Haploptychius bombax - Kobelt 1906: 147, 148, pl. 63, figs 7-9. Richardson 1988: 212.

Material examined.

Syntype UMZC I.102470 (3 shells; Fig. 9A ) from Moulmein. India [error]: NHMUK ex. Cuming collection (1 juvenile). Moulmein: NHMUK 1903.7.1.3990 (4 shells; Fig. 9D ) ex. Godwin-Austen collection. NHMUK 1906.2.2.159 (1 juvenile; Fig. 9B ) ex. Blanford collection. NHMUK 1906.2.2.340 (2 shells) ex. Blanford collection. NHMUK ex Godwin-Austen collection (2 shells). NHMUK 1888.12.4.768-770 (3 shells; Fig. 9C ) .

Diagnosis.

Haploptychius bombax can be differentiated from H. burmanicus by having a large oblique-ovate shell, without sinulus, and larger or wider last whorl. In contrast, H. burmanicus possesses a small sub-oblique heliciform shell, wide sinulus, and compressed last whorl. Compared with H. pellucens (Pfeiffer, 1863) from Laos, H. bombax differs by having strong radial ridges, convex spire, and narrow umbilicus, while H. pellucens exhibits a nearly smooth surface, more ovate shape, elevated spire, and umbilicus widely open.

Description.

Shell oblique-ovate, white, and translucent; whorls 5½ -7; spire convex with distinct suture. Shell surface glossy with fine transverse ridges that diminish below periphery of penultimate whorl. Embryonic shell ~ 2½ whorls with smooth surface; following whorls regularly coiled. Shell periphery rounded; last whorl axially deflected. Aperture semi-ovate; peristome discontinuous, thickened, slightly expanded, and reflected. Apertural dentition with one strong parietal lamella. Umbilicus open and deep (Fig. 9 ).

Distribution.

Haploptychius bombax is only known from the type locality in southeastern Myanmar ( Benson 1859b).

Remarks.

The original description mentioned only 5½ whorls, but the museum specimen (Fig. 9C, D ) had 7 whorls. This study collected no specimens, but authenticated museum specimens (juveniles and adults) were examined.

Figures

Figure 9. Haploptychius bombax A syntype UMZC I. 102470 from Moulmein B juvenile specimen NHMUK 1906.2.2.159 from Moulmein C specimen NHMUK 1903.7.1.3990 from Moulmein with apertural dentition D specimen NHMUK 1888.12.4.768 - 770 from Moulmein with apertural dentition.