Rishetia hastula ( Benson, 1860 )

Man, Nem Sian, Ablett, Jonathan D., Lwin, Ngwe, Sutcharit, Chirasak & Panha, Somsak, 2024, Contributions on a small collection of the former Subulinidae Fischer & Crosse, 1877 (Eupulmonata, Achatinoidea) with catalogue of the Glessula and Rishetia species recorded from Myanmar, ZooKeys 1208, pp. 173-239 : 173-239

31 Rishetia hastula ( Benson, 1860)

Fig. 14 D

Achatina hastula Benson, 1860: 461. Type locality: ad Pankabari, prope Darjiling [Pankhabari, near Darjiling, West of Bengal, India]. Pfeiffer 1868: 235.

Achatina (Electra) hastula — Hanley and Theobald 1870: 9, pl. 18, fig. 4.

Stenogyra (Glessula) hastula — Nevill 1878: 169.

Stenogyra (Subulina) hastula — Pfeiffer and Clessin 1881: 327.

Glessula hastula — Theobald and Stoliczka 1872: 334. Beddome 1906: 167. Pilsbry 1909: 93, pl. 12, fig. 12. Gude 1914: 414. Ramakrishna et al. 2010: 161

Glessula (Rishetia) hastul a — Godwin-Austen 1920: 16, 17, pl. 161. figs 16, 17, pl. 163. figs 9, 9 a, 10.

Rishetia hastula — Budha et al. 2017: 139, figs 2 d, 6. Preece et al. 2022: 127, 128, fig. 55 a.

Type specimen.

Neotype NHMUK 1906.1 . 1.880 (designated in Preece et al. 2022: 127, fig. 55 a) (Fig. 14 D ) ex. Blanford collection from Darjiling.

Diagnosis.

Shell elongate, turreted, and regularly attenuated; apex rounded and blunt; subsequent whorls coarse with fine equally spaced radial ridges throughout. Suture somewhat impressed and whorls convex. Aperture broadly ovate; columella strong, concave, and truncated.

Distribution.

The species was originally described from India and later recorded from Nepal ( Ramakrishna et al. 2010; Budha et al. 2015; Kalita 2022). In Myanmar, it was reported from Kumah Hill and Maii [Ma-ei Town ~ 19 ° 20 ' 36.5 " N, 94 ° 08 ' 21.9 " E], which are in the Thandwe District, Rakhine State in the westernmost part of Myanmar ( Theobald and Stoliczka 1872; Gude 1914; Godwin-Austen 1920).

Remarks.

To clarify the taxonomic status of this species, Preece et al. (2022) have designated a neotype based on the specimen figured in Hanley and Theobald (1870, pl. 18, fig. 4). However, the image used to represent the neotype in Preece et al. (2022: fig. 55 a) is an erroneous repetition of ‘ Achatina leptospira Benson, 1865 ’ (see Preece et al. 2022: fig. 51 f). Therefore, the correct image of the neotype NHMUK 1906.1. 1.880 is illustrated herein.

Theobald and Stoliczka (1872: 334) noted that the specimens from Arakan tended to differ from the type specimen in having a larger shell size. Nevertheless, Arakan and Sikkim are non-adjacent regions and far apart, which raises doubts about whether they are the same or distinct species.

Figures

Figure 14. A – C Rishetia burrailensis maxwelli A, B specimen NHMUK 1903.7. 1.3742 from Somra Tracts, Somra Khulen Post, Burma and C specimen NHMUK 1903.7. 1.3744 from Somra Tracts, Somra Khulen Post, Burma D Rishetia hastula, neotype NHMUK 1906.1. 1.880 from Darjiling E, F Rishetia kentungensis, syntypes NHMUK 1903.7. 1.3650 from Mong Sing, Siam Boundary G Rishetia limborgi, holotype NHMUK 1903.7. 1.3200 from Tenasserim H, I Rishetia nathiana, syntypes NHMUK 1906.1. 1.2206 from Bassein District.