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).

 
 
  Part of: Tongkerd P, Tumpeesuwan S, Inkhavilay K, Prasankok P, Jeratthitikul E, Panha S, Sutcharit C (2023) Systematic revision of the snorkel snail genus Rhiostoma Benson, 1860 (Gastropoda, Caenogastropoda, Cyclophoridae) with descriptions of new species. ZooKeys 1142: 1-144. https://doi.org/10.3897/zookeys.1142.90097