New Insight on the Presence of Several Freshwater Gastropod Species Considered Rare in Serbia

Abstract

The freshwater gastropod fauna of Serbia can be considered understudied compared to the neighbouring countries. This is especially true for the species that frequently occur in smaller and transient habitats such as Aplexa hypnorum (Linnaeus, 1758), Physa fontinalis (Linnaeus, 1758), Anisus (Disculifer) vorticulus (Troschel, 1834), Hippeutis complanatus (Linnaeus, 1758) and Segmentina nitida (O.F. Müller, 1774). Our survey of various smaller habitats in the Pannonian part of Serbia took place in 2021 and 2022 and included 11 sites. One or more of the above-mentioned snail species were found at nine of these sites. Of particular interest are the findings of A. hypnorum, the species whose last and only confirmed finding dated back to the beginning of the 20th century. In total, we present three new localities of A. hypnorum and S. nitida. The number of known localities of A. vorticulus and H. complanatus has doubled (now seven and eight localities respectively). Physa fontinalis, a native species once quite common in the Pannonian areas, is with a declining frequency. During our survey, an abundant population of P. fontinalis was found at a new site. The results presented suggest that a comprehensive survey focusing on smaller and neglected habitats is necessary to fill the gaps in our knowledge of the occurrence and distribution of the freshwater gastropod fauna in Serbia.