Haploptychius solidulus (Stoliczka, 1871)

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 solidulus (Stoliczka, 1871)

Figs 1 , 11

Streptaxis solidulus Stoliczka, 1871: 166, pl. 7, fig. 10. Type locality: Moulmein, Tenasserim [Mawlamyine District, Mon State, Myanmar]. Pfeiffer 1876: 494. Hanley and Theobald 1870: 40, pl. 98, fig. 7. Nevill 1878: 3. Tryon 1885: 71, pl. 14, fig. 99. Gude 1903: 212. Blanford and Godwin-Austen 1908: 7. Kobelt 9010: 152.

Haploptychius solidulus - Richardson 1988: 221, 222.

Material examined.

Moulmein : NHMUK 1937.7.9.10 (1 shell). NHMUK 1906.2.2.339 (1 shell) ex. Blanford collection. NHMUK 1888.12.4.774-776 (3 shells; Fig. 11B ). NHMUK 1909.3.15.75 (1 shell; Fig. 11A ) ex. Godwin-Austen collection. Pathen Mountain , east bank of Attaran River and ~ 45 km southeast of Kyaikmaraw Township, Mawlamyine District, Mon State, Myanmar (16°14'7.5"N, 97°56'48.1"E): CUMZ 13007 (15 shells; Fig. 11C, D ) .

Diagnosis.

Among the Haploptychius species from Myanmar, this species is distinctly large with an oblique-ovate shell, and less deflected last whorl. Haploptychius solidulus has almost the same shell form as Oophana mouhoti . However, it differs from O. mouhoti by having somewhat enlarged last whorl, more deflected last whorl, and a conical spire with only one parietal lamella. In contrast, O. mouhoti shows a depressed and obtuse conical spire, with one parietal and small basal lamellae.

Description.

Shell oblique-ovate, white, and opaque; whorls 6½ -7; spire elevated conical with distinct suture. Shell surface glossy with fine transverse ridges that diminish below periphery. Embryonic shell ~ 2½ whorls with smooth surface; following whorls regularly coiled. Shell periphery rounded; last whorl axially deflected. Aperture semi-ovate; peristome discontinuous, thickened, expanded, and slightly reflected. Apertural dentition with one strong parietal lamella. Umbilicus open and deep (Fig. 11 ).

Distribution.

This species appears to be restricted to limestone karsts and is only recorded from southern Myanmar.

Remarks.

Stoliczka (1871) mentioned the specimens received from Theobald, who collected at Yethebiankoo [Rathe Pyan Cave] on the Attaran river, south-east of Moulmein [Mawlamyine]. Therefore, the exact type locality is assumed to be Rathe Pyan Cave, but it is located southwest of Hpa-an, Kayin State. Unfortunately, no living specimens could be examined.

Figures

Figure 1. Approximate sampling locations used in this study. The location name and coordinates are listed in Table 1. Historical type localities of a broad scale, such as Tavoy, Burma, Moulmein, Mergui, and Tenasserim, are not indicated on this map.

Figure 11. Haploptychius solidulus A specimen NHMUK 1909.3.15.75 from Moulmein with apertural dentition B specimen NHMUK 1888.12.4.774 - 776 from Molumein C, D specimen CUMZ 13007 from Pathen Mountain, Mawlamyine, Mon State with apertural dentition.