Rishetia pertenuis major ( Blanford, 1865 ) 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

36 Rishetia pertenuis major ( Blanford, 1865) comb. nov.

Fig. 15 F, G

Achatina pertenuis var. major Blanford, 1865: 79. Type locality: Pyema Khyoung, Bassein District, Pegu [PyayMa Khaung or Pyinma Khuang, Pathein Township, Pathein District, Ayeyarwady Region, Myanmar].

Glessula pertenuis var. major — Gude 1914: 381. Godwin-Austen 1920: 53.

Type specimen.

Possible syntypes NHMUK 1906.1. 1.2208 (6 shells; Fig. 15 F, G ) ex. Blanford collection from Pyema Khyoung , Bassein; label state ‘ Glessula basseinensis G-A. ’

Diagnosis.

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

Distribution.

This subspecies was known solely from the type locality.

Remarks.

When describing ‘ Achatina pertenuis ’, Blanford (1865) recognised the larger shells as a distinct variety and gave them the name ‘ var. major ’. This taxon name was made available, although without description, because the two sets of shell dimensions and materials from ‘ Pyema Khyoung, Bassein district, Pegu’ confer the indication ( ICZN 1999: Arts 11.9 and 12).

The type series of the taxa could not be traced. Only one specimen lot from the Godwin-Austen collection belongs to W. T. Blanford’s original type series., i. e., NHMUK 1906.1. 1.2208, with the original label in Godwin-Austen’s handwriting marked ‘ ex. duplicate collection Blf., intermediate between A. tenuispira and A. pertenuis ’, with a species name ‘ Glessula basseinensis G-A. ’, and collection locality ‘ Pyema Khyoung, Bassein’. Therefore, this specimen lot is here considered as possible syntype material, and the two shells closest to the shell measurements given in the original description are illustrated herein.

The modern name of ‘ Pyema Khyoung, Bassein District, Pegu’ is the PyayMa Khaung or Pyinma Khuang (~ 18 ° 38 ' 51.7 " N, 95 ° 45 ' 46.9 " E), Pathein Township, Pathein District, Ayeyarwady Region, Myanmar.

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.