Rishetia tenuispira ( Benson, 1836 )

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

37 Rishetia tenuispira ( Benson, 1836)

Fig. 15 H

Achatina tenuispira Benson, 1836: 353. Type locality: N. E. Frontier of Bengal. Pfeiffer 1848: 262. Reeve 1849 a: Achatina, pl. 16. Benson 1860: 464. Pfeiffer 1860: 310, 311 pl. 25, figs 6, 7. Blanford 1865: 95.

Subulina tenuispira — Adams and Adams 1855: 110.

Achatina (Subulina) tenuispira — Pfeiffer 1856: 169.

Achatina (Electra) tenuispira — Hanley and Theobald 1870: 17, pl. 36, fig. 8.

Stenogyra (Glessula) tenuispira — Nevill 1878: 169.

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

Glessula tenuispira — Beddome 1906: 160. Pilsbry 1909: 88, pl. 9, figs 1, 4. Gude 1914: 378. Godwin-Austen 1920: 31, 32.

Rishetia tenuispira — Raheem et al. 2014: 138, fig. 90 c. Budha et al. 2017: fig. 14 c. Preece et al. 2022: 128, fig. 55 b.

Type specimen.

The type specimen could not be located in the UMZC collection ( Raheem et al. 2014; Preece et al. 2022). However, Budha et al. (2017: fig. 14 a) figured a possible syntype of this species based on specimens ex. Benson collection from ‘ Teria Ghat’, this specimen lot was not considered to form part of the type series by Preece et al. (2022).

Other material.

NHMUK 1946.10. 16.1–7 (7 shells) ex. R. McAndrew collection from Pegu. NHMUK 1903.7. 1.3332 (1 shell; Fig. 15 H ) labelled as ‘ var. ’ ex. Godwin-Austen collection from Garo Hills. UMZC I. 102045 from Teria Ghat ( Budha et al. (2017: fig. 14 a) recognised this specimen as a possible syntype).

Diagnosis.

Shell elongate, turreted, and regularly attenuated; apex rounded; subsequent whorls with fine equally spaced radial ridges throughout and more prominent near suture. Suture impressed and whorls slightly flattened. Aperture elongate ovate; columella concave and truncated.

Distribution.

This species is broadly distributed in Bangladesh, India, and Nepal ( Budha et al. 2015; Preece et al. 2022). It was also reported from several localities in the southwest and eastern Myanmar: Ayeyarwady, Bago, and Tanintharyi regions ( Benson 1860; Blanford 1865; Beddome 1906).

Remarks.

Benson (1860: 464) reported that Theobald found a variety of ‘ Achatina tenuispira ’ on the banks of Irrawaddy [Ayeyarwady River] and from Phie Than [probably in Tanintharyi Region]. Blanford (1865) recorded the presence of a small-sized species in Akoutoung [Akauk Taung, Ayeyarwady Region] and further south, while Beddome (1906) noted its occurrence in Pegu [Bago Region].

Figures

Figure 15. A – E Rishetia pertenuis A, B possible syntypes NHMUK 1906.2. 2.239 from Henzada, Pegu and Tongoop, Arakan C specimen NHMUK from Tongoop, Arakan and D, E specimen NHMUK 1888.12. 4.1229–31 from Pegu F, G Rishetia pertenuis major, possible syntypes NHMUK 1906.1. 1.2208 from Pyema Khyoung, Bassein H Rishetia tenuispira, specimen NHMUK 1903.7. 1.3332 from Garo Hills.