Taxonomy of Terrestrial Molluscs of Nepal

Date: 14 July 2017

Venue: Stadscampus, S.M.002 (De Meerminne) - Sint-Jacobstraat 2 - 2000 Antwerpen (route: UAntwerpen, Stadscampus)

Time: 3:00 PM

Organization / co-organization: Department of Biology

PhD candidate: Prem Bahadur BUDHA

Principal investigator: Thierry Backeljau & Fred Naggs

Short description: Public defence of the PhD thesis of Mr. Prem Bahadur BUDHA - Faculty of Science - Department of Biology


Taxonomic research of the terrestrial malacofauna in the Indian subcontinent began at the end of the 18th and the beginning of the19th century by British malacologists. Yet, Nepal was largely neglected and this remained so until recently due to the lack of (1) taxonomic infrastructure, (2) trained native taxonomic experts and (3) collaborative research efforts with the global malacological community. Therefore, this PhD thesis attempts to be the start of a comprehensive study of the terrestrial malacofauna of Nepal. It starts by presenting the very first checklist of the terrestrial snails of Nepal, which serves as faunistic baseline for the remainder of the thesis and future research. At the start of this PhD work, this checklist provided nomenclatural and faunistic information on 138 species belonging to 28 family, 60 genera, and 16 subgenera, with 34 species recorded as new in Nepal. Yet, as a result of this PhD research, the checklist now comprises 158 species that are known from Nepal.

The remainder of this PhD work deals with the taxonomy of six problematic land snail taxa in Nepal, viz. the caenogastropod genus Diplommatina, and the stylommatophoran genera Darwininitium, Glessula, Rishetia, Endothyrella, and Paraboysidia. As such, 17 species are described as new for science, viz. seven species of Diplommatina, one species of Darwininitium, one species of Glessula, five species of Rishetia, and three species Endothyrella. In addition, one monotypic genus new to science is also described, viz. Darwininitium. Initially this genus was  supposed to belong to the family Cerastidae and to represent an exceptional case of pseudosigmurethry, but recent DNA data have shown that this taxon should be synonymized with the camaenid genus Ganesella, implying that it is a fully sigmurethrous taxon.

Besides providing descriptions of new taxa, this PhD research also includes a critical revision of the genus Endothyrella in China, India and Nepal, and presents the very first identification keys for the genera Glessula, Rishetia, and Diplommatina in Nepal.

Finally, the study of the genus Paraboysidia showed that there is a complex taxonomic problem with the interpretation of the closely related genus Bensonella with its type species Helix plicidens, while the study of the genera Glessula and Rishetia tentatively suggests that there are consistent conchological and anatomical differences between these two taxa.

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