Rishetia basseinensis ( Godwin-Austen, 1920 ) Man & Ablett & Lwin & Sutcharit & Panha, 2024

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

29 Rishetia basseinensis ( Godwin-Austen, 1920) comb. nov.

Fig. 13 E, F

Achatina pertenuis var. major Blanford, 1865: 79 [in part].

Glessula basseinensis — Godwin-Austen 1920: 54, pl. 161. fig. 3, pl. 164, fig. 12. Type locality: Bassein, Pegu and Pyema Khyoung, Bassein.

Type specimens.

Syntypes NHMUK 1909.3. 15.19 [re-registered in error as 1985139] (3 shells; Fig. 13 E, F ) ex. Blanford ex. Godwin-Austen collection from Bassein , Pegu .

Diagnosis.

Shell slender, elongate turreted and regularly attenuated; apex rounded and blunt; subsequent whorls with fine and equally spaced radial ribs, which more prominent near suture. Suture impressed and whorls flattened convex. Aperture ovate; columella strong, concave, and truncated.

Distribution.

Rishetia basseinensis appears to be restricted within Myanmar and is known only from the type locality. Based on the current administrative boundary, ‘ Bassien (or Pathein), Pegus’ is in the Pathein Township, Pathein District, Ayeyarwady Region, rather than Pegu [Bago Region].

Remarks.

Godwin-Austen (1920: 53) stated that when examining the type series of ‘ Glessula pertenuis var. major ’ ex. Blanford collection, he found it very different from the nominotypical taxon, and described this specimen lot under a different name, ‘ Glessula basseinensis ’. In the original description, Godwin-Austen (1920: 54) provided two collection localities, namely ‘ Bassein, Pegu’ and ‘ Pyema Khyoung, Bassein’ and comparing three and six specimens, respectively. The description clearly states a catalogue number ‘ Type No. 19.9.3.15 B. M. ’ and includes an illustration of specimens from ‘ Bassein, Pegu’. The NHMUK collection contains this specimen lot NHMUK 1909.3. 15.19 consisting of three shells with an original label in Godwin-Austen’s handwriting stating ‘ Type’ from the H. F. Blanford collection. The specimen with a similar shell measurement given in the original description and with pink wool inside the shell is figured herein (Fig. 13 E ). Additionally, one further shell from the same syntype lot is also illustrated (Fig. 13 F ).

The specimen lot NHMUK 1909.1. 1.2208 is excluded from the type series of this species (see also under the Rishetia pertenuis major ).

Figures

Figure 13. A – C Rishetia akouktoungensis, syntypes NHMUK 1906.1. 1.2207 from Akouktoung, Pegu D Rishetia baculina, syntypes NHMUK 1909.3. 15.9 from Kursiong, Darjiling E, F Rishetia basseinensis, syntypes NHMUK 1909.3. 15.19 from Bassein G – I Rishetia burrailensis maxwelli G holotype NHMUK 1903.7. 1.1717 / 1 from Naga Hills, East of Kohima H specimen NHMUK 1988147 from Somra Tracts, Somra Khulen Post, west of Kyengdwen River, Burma and I paratypes NHMUK 1903.7. 1.1717 / 2–4 from Naga Hills, East of Kohima.