Original paper
Variability and taxonomy of South Caucasian freshwater snails of the genus Shadinia Akramowski, 1976 (Caenogastropoda: Hydrobiidae) based on new morphological and molecular data
Sitnikova, Tatiana Ya.; Peretolchina, Tatiana E.; Anistratenko, Vitaly V.; Anistratenko, Olga Yu.; Palatov, Dmitry M.
Archiv für Molluskenkunde International Journal of Malacology Band 147 Heft 1 (2018), p. 63 - 76
44 references
published: Jun 29, 2018
published online: Jun 29, 2018
DOI: 10.1127/arch.moll/147/063-076
Open Access (paper may be downloaded free of charge)
Abstract
Within the genus Shadinia Akramowski, 1976, 8 groups have been differentiated by their conchology and male/female genital anatomy. One of these groups is treated as the monomorphic species S. akramowskii (Shadin, 1952) while 7 others are morphs of the polymorphic S. terpoghassiani (Shadin, 1952). In 5 out of the 8 designated groups, p-distances for COI gene sequences were less than 1%, which corresponds to intraspecific distances of a single species. The 2 species, S. terpoghassiani (type species of genus Shadinia) and S. akramowskii, have been found sympatrically only at a single locality, where the p-distance between them is higher than between the same species from separate localities. In the type series of S. terpoghassiani, all shells bear a well-developed spiral keel, except for a single snail with a smooth shell, which was named S. terpoghassiani morpha ecarinata Akramowski, 1976. This keel-less morph is characterized by sexual dimorphism; the females are similar to S. akramowskii in the shape of the shell, but the males resemble S. bjniensis Bößneck, Walther & Neiber, 2016. The presence of sexual dimorphism, a unique trait for the ecarinata morph, could lead to considering this morph as a distinct species, but COI gene sequences are identical to S. bjniensis (with no sexual dimorphism observed) and demonstrate conspecificity of these species. We provide the detailed characteristics for S. akramowskii and the 7 morphs of S. terpoghassiani. Attribution of Hydrobia sieversi O. Boettger, 1881 to the genus Shadinia is still uncertain due to the lack of anatomical and molecular data. The taxonomic structure of the genus and possible diversification patterns within the genus are discussed.
Keywords
South Caucasian gastropods • shell measurements • genital anatomy • COI gene sequences • taxonomy