Opisthoporus herosae (Thach & Huber, 2017)

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 herosae (Thach & Huber, 2017)

Fig. 58A, B

Rhiostoma herosae Thach & Huber in Thach 2017: 17, figs 87-89. Type locality: Ninh Binh Province, North Vietnam. Páll-Gergely et al. 2020a: 40. Do et al. 2020b: 166, fig. 1a.

Rhiostoma ninhbinhensis Thach & Huber in Thach 2018: 17, figs 81a, 82a, 83a, b. Type locality: Ninh Binh Province, Central Vietnam.

Type material.

Holotype MNHN-IM-2000-33198 (Fig. 58A ) from Ninh Binh Province. Holotype FMNH 386285 (Fig. 58B ) of Rhiostoma ninhbinhensis Thach & Huber, 2018, from Ninh Bình, Vietnam.

Remarks.

This species description was based on the holotype and four paratypes. Páll-Gergely et al. (2020a) stated that the holotypes of R. herosae and R. ninhbinhensis are identical in all shell size characters and they share the same type locality in Ninh Binh Province; therefore, they treated the latter as a junior synonym of the former species. Do et al. (2020b) agreed with this treatment and have made several attempts to collect R. herosae from Ninh Binh Province (type locality) and neighbouring provinces, but have not found any specimens identifiable to this species.

This species differs from other Rhiostoma species in having a multispiral, slightly concave, and plate-shaped operculum, which are the distinguishing characters of the Opisthoporus (see Do et al. 2020a). We agree with the previous synonymisation and here have also placed this species in the genus Opisthoporus .

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).