Glessula blanfordiana Nevill, 1877

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

8 Glessula blanfordiana Nevill, 1877

Fig. 5 A – D , Table 1

Glessula blanfordiana Nevill, 1877: 26. Type locality: Ponsee, Yunnan [Ponsee, Kahkyen Hills, Yunnan Province, China]. Beddome 1906: 171. Pilsbry 1909: 98, pl. 13, fig. 11. Gude 1914: 437, 438. Godwin-Austen 1920: 56, pl. 164, fig. 21.

Stenogyra (Glessula) blanfordiana — Nevill 1881: 138, pl. 5, fig. 12.

Type specimens.

Syntypes NHMUK 1988150 (2 shells; Fig. 5 A, B ) ex. Godwin-Austen collection from Ponsee, Yunnan, W. China.

Other material.

Aik Kham Cave, Taunggyi Township, Taunggyi District, Shan State, Myanmar (20 ° 49 ' 07.0 " N, 97 ° 13 ' 42.0 " E): CUMZ 13067 (3 shells; Fig. 5 C, D ).

Description.

Shell ovately conical, solid, brownish colour, and with 6–6 ½ whorls. Apex rounded; protoconch ~ 2 whorls with weak radial striations; subsequent whorls with equally and widely spaced ribs, more raised, and coarser near suture of last whorl. Spire regularly attenuated, slightly turreted; whorls convex; suture deep; last whorl largest. Aperture obliquely and narrowly ovate; peristome white and thickened; columella short, concave, slightly twisted and abruptly truncated. Umbilicus closed.

Distribution.

This species was originally described from Yunnan, China, and subsequently reported from Bhamo, Kachin State, Myanmar ( Nevill 1881). In this study, new material has been collected from Shan State, which borders Yunnan to the east and Bhamo to the north.

Remarks.

When nominating this species, Nevill (1877: 26) compared it with G. peguensis ( Blanford, 1865) from Bago and stated that G. blanfordiana has slender (less convex) whorls, wavy or curving, and stronger radial ribs. Nevertheless, the type specimens of these two species, G. blanfordiana (height 8–9 mm, Fig. 5 A, B ) and G. peguensis (height ~ 7 mm, Fig. 10 B, C ), exhibit considerable similarity in terms of shell shape and shell size. Therefore, more specimens from the Bago Region are necessary to ascertain whether the difference in shell sculptures represents variations or are taxonomically informative characters separating these two species.

Glessula blanfordiana examined herein are noticeably distinct from their congeners recorded in Shan State and Mandalay Region, namely G. feddeni Godwin-Austen, 1920 and G. latestriata von Möllendorff, 1899 . Specifically, G. blanfordiana has a shorter and bluntly attenuated spire, more bulging whorls, deeper suture, and stronger and densely radial ribbed sculptures. In contrast, the other species exhibit higher and pointed spires, more flattened whorls, and smooth to radial grooves sculptures (see Fig. 2 D ).

Glessula blanfordiana was described based on two specimens collected by J. Anderson during the Expedition to Yunnan and Upper Burma. The original description was very brief, without shell dimensions and illustrations. However, under the note of G. ponsiensis Godwin-Austen, 1920 , states, ‘ The type from Ponsee, Yunnan (Plate CLXIV. fig. 20, apex) [= G. blanfordiana ], has been sent me from Calcutta by the Director of the Zoological Survey of India, Dr. N. Annandale … ’ ( Godwin-Austen 1920: 56). The NHMUK type collections contain a single lot with an original label stating ‘ Type’ from ‘ Dr. J. Anderson’, and collection locality from ‘ Ponsee’. These two specimens match well with the species description; both are figured herein for the first time. It is possible that N. Annandale may have gifted this type specimen lot to Godwin-Austen for comparison with other species, as was the case with other specimens from the Zoological Survey of India.

Figures

Figure 2. Schematic shell morphology of the subulinid snails A protoconch sculptures as recognised in this study: smooth and striate B crenulate suture C columella shape as recognised in this study: straight, truncate and fold D shell surface sculpture of the Glessula as recognised in this study: smooth, groove, and ribbed.

Figure 5. A – D Glessula blanfordiana A, B syntypes NHMUK 1988150 from Ponsee, Yunnan, W. China and C, D specimen CUMZ 13067 from Taunggyi, Shan State, Myanmar E, F Glessula crassilabris E syntype UMZC I. 102430 from Bengal (after Preece et al. 2022: fig. 51 e) and F specimen NHMUK from Cherrapoonji (M 10604 / 2).

Figure 10. A Glessula orophila, specimen NHMUK ex. Blanford collection from Mahableshwar B, C Glessula peguensis, specimen NHMUK 1909.3. 15.8 from Thyet-Myo D, E Glessula perlevis, syntypes NHMUK 1906.5. 5.89 from Shan Hills, Burma F Glessula ponsiensis, syntypes NHMUK 1989042 from Ponsee.