Bertia pergrandis (Smith, 1893)

Sutcharit, Chirasak, Naggs, Fred, Ablett, Jonathan, Sang, Pham Van, Luong Van Hao, & Panha, Somsak, 2019, Notes on the sinistral helicoid snail Bertia cambojiensis (Reeve, 1860) from Vietnam (Eupulmonata, Dyakiidae), ZooKeys 885, pp. 1-14 : 1

Bertia pergrandis (Smith, 1893) Fig. 3A

Rhyssota pergrandis Smith, 1893: 11, with text figure. Type locality: Annam.

Nanina pergrandis : Fischer and Dautzenberg 1904: 4.

Ariophanta pergrandis : Schileyko 2011: 29.

Bertia pergrandis : Thach 2015: 214, figs 9-12. Thach 2016: 62, pl. 18, fig. 270, pl. 19, fig. 272.

Material examined.

Syntype NHMUK 1893.2.26.1 (1 shell, Fig. 3A ).

Remarks.

Ariophanta ranges from India to Indochina ( Godwin-Austen 1888, Schileyko 2003) and includes large species with both dextral and sinistral shells. Although the reproductive anatomy of Ariophanta and Bertia are quite distinct the sinistral shells exhibit a close convergence in shell form and definitive generic attribution requires investigation of reproductive anatomy or molecular evidence. We provisionally follow Thach (2015) in attributing this species to Bertia based on its very close similarity to the type species in shell form and colour and to the presence of earlier whorls with nodules arranged along the growth lines. Bertia pergrandis differs from the type and following species in possessing a stronger peripheral keel and widely open umbilicus; the other species exhibit a rounded last whorl and rimate umbilicus.

Figures

Figure 3. A Bertia pergrandis, syntype NHMUK 1893.2.26.1 B Bertia setzeri, holotype ANSP 466244.