A study on faunistic and geographical distribution of freshwater snails (Gastropoda) in northwest of Iran

Among the most frequently found groups of mollusks are freshwater gastropods that play a substantial role in the health of aquatic and terrestrial ecosystems and also in the health of human communities because they are the intermediate hosts of some parasites such as trematodes and nematodes. Consequently, it is very important to know their morphology and study their ecology, which the present research addresses. For this purpose, specimens of freshwater gastropods were taken from 52 stations in East Azerbaijan, Ardabil and West Azerbaijan Provinces during 2015-2020. They were mostly collected by hand and, if possible, transferred to the laboratory after photographing them and recording their habitat characteristics together with their sympatric species that were found. To identify the species more accurately, shell characteristics and reproductive organs were studied. Among the 288 studied specimens, 11 species belonging to nine genera and six families were observed, and 55 % of the species (six spp.) were reported for the first time from this region. The greatest species diversity was found in the Radix genus of the Lymnaeidrae family. The dominant species found in most of the studied stations were Radix bactriana (٪26), Physella acuta (٪19) and Stenochlaena palustris (٪12.8).