Nominal taxa of freshwater Mollusca from Southeast Asia described by Dr. Nguyen N. Thach: A brief overview with new synonyms and fixation of a publication date

Abstract

In this correspondence, we present a summary of taxonomic names of freshwater Mollusca introduced by Dr. Nguyen N. Thach, an enthusiastic and productive malacologist from Vietnam. We show that this researcher described one new genus and 12 new nominal species of freshwater molluscs from Southeast Asia. Two of these nominal species, Sinanodonta hunganhi Thach, 2016 and Lanceolaria bogani Thach, 2016 (Bivalvia: Unionidae), were already considered junior synonyms of S. jourdyi (Morlet, 1886) and L. fruhstorferi (Dautzenberg, 1900), respectively (Do et al. 2018; Đặng and Hố 2019). Here, we propose one more synonym for the invasive Golden Apple Snail as follows: Pomacea canaliculata (Lamarck, 1822) [=Pomacea thachi Huber in Thach, 2020 syn. nov.] (Gastropoda: Ampullariidae). Furthermore, we establish the formal synonymy for the following taxa: Taia Annandale, 1918 [=Boganmargarya Thach, 2018 syn. nov.]; Taia shanensis (Kobelt, 1909) [=Boganmargarya huberi Thach, 2018 syn. nov.] (Gastropoda: Viviparidae); Brotia henriettae (Gray in Griffith & Pidgeon, 1833) [=Brotia frankhuberi Thach, 2020 syn. nov.; Brotia bogani Thach & Huber in Thach, 2020 syn. nov.] (Gastropoda: Pachychilidae); Pila pesmei (Morlet, 1889) [=Pila huberi Thach, 2020 syn. nov.] (Gastropoda: Ampullariidae); and Paludomus andersoniana Nevill, 1877 [=Paludomus huberi Thach, 2020 syn. nov.] (Gastropoda: Paludomidae). Additionally, four nominal species are treated here as taxa inquirenda: Melanoides thachi Huber in Thach, 2020 (Gastropoda: Thiaridae), Trochoita frankohleri Thach & Huber in Thach, 2020 (Gastropoda: Viviparidae), Paracrostoma huberi Thach, 2018 (Gastropoda: Pachychilidae), and Pseudodon artbogani Thach & Huber in Thach, 2020 (Bivalvia: Unionidae). We also show that the publication date written on the title page of the book “New Shells of South Asia. Volume 2” (Thach, 2020a) is a bit misleading and that this book appeared in the printed form on 23 June 2020. The latter date is fixed here as the date of availability of taxonomic names introduced in this work. Finally, we present an annotated checklist of freshwater Mollusca described by N. N. Thach with approximate coordinates of the type localities and reference to corresponding river drainage basins.