Physidae (Mollusca: Gastropoda) of western and central European range - morphological diversification and ecological features

Abstract Background: This is the first comparative study on Physidae identified in west and central Europe range. A thorough exploration of morphology supported by ecological features and distribution of European Physidae species are presented within this study. In the context of the lack of research on detailed morphology features on Physidae species we deeply analysed taxonomical features of snails which are being identified more and more frequently in the last years in the territory of the west and central Europe. Scanning electron microscopy (SEM) methods were used to elucidate the external morphology of freshwater snails (Mollusca: Gastropoda: Physidae), that occur in the area of western and central part of Europe. We compared the external morphology of their shells and found important differences between the species. Results: Morphological analysis are benefited in revealing variations of Physide shells. We found intraspecific similarities within Physidae, which are the most evident in the overall structure of shells and the height of the spires. Many interspecific differences in morphology in the apex structure and spires were found. From our results, we can infer that the shells P. fontinalis and A. hypnorum had the lowest amount of variability between particular individuals. The most characteristic features and differences of representatives of Physidae are presented and discussed. This is especially important in Physa gyrina and a worldwide invader Physa acuta identification which is shape-wise not easy to distinguish.Conclusions: The implications of our study are new identification key along with the ecological characteristic of physid species and the assessment of their current range in Europe. Our data demonstrate similarities within Physidae, which are the most evident in the overall structure of shells, and the height of the spires, apex structure, and spires were found between analysed species and provide further evidence of the importance of morphological features as an identification driver.