Opisthoporus thorsengi (Thach, 2020)

Tongkerd, Piyoros, Tumpeesuwan, Sakboworn, Inkhavilay, Khamla, Prasankok, Pongpun, Jeratthitikul, Ekgachai, Panha, Somsak & Sutcharit, Chirasak, 2023, Systematic revision of the snorkel snail genus Rhiostoma Benson, 1860 (Gastropoda, Caenogastropoda, Cyclophoridae) with descriptions of new species, ZooKeys 1142, pp. 1-144 : 1

Opisthoporus thorsengi (Thach, 2020)

Fig. 58E

Rhiostoma thorsengi Thach, 2020: 19, 20, figs 157, 158. Type locality: Krong No District, Dak Nong Province, Central Vietnam.

Type material.

Holotype BOR/ MOL 14587 (Fig. 58E ) from Krong No District, Dak Nong Province.

Remarks.

This species was described based on a single specimen with a worn shell, eroded protoconch, and without a periostracum. The unique characters are a circular peristome, slightly thickened but not expanded lip, a tubular breathing device curved and pointed posteriorly, and a short detached whorl. These characteristics have led us to classify this species as a member of the Opisthoporus (see Do et al. 2020a).

Figures

Figure 58. A, B Opisthoporus herosae A holotype MNHN-IM- 2000 - 33198 from Ninh Binh, Vietnam and B holotype FMNH 386285 of Rhiostoma ninhbinhensis Thach & Huber, 201, from Ninh Binh, Vietnam C Opisthoporus ngocngai holotype FMNH 386291 from Ninh Hao, Vietnam D Opisthoporus ngocthachi holotype MNHN-IM- 2000 - 35508 from Khanh Hoa, Vietnam E Opisthoporus thorsengi holotype BOR / MOL 14587 from Dak Nong, Vietnam F Opisthoporus tener specimen NHMUK ex. Cuming collection. Photographs: M Caballer, A Lardeur and V Heros, MNHN (A, D, F), J Gerber, FMNH (B, C), T-S Liew, BORNEENSIS (E).