Morphological variability of trematodes from bats (Chiroptera) is poorly studied. Since the variability of adult digenean specimens may be rather high, morphological features are often insufficient for the identification of closely related species, and confirmation with the use of molecular data is required. The aim of our study was to combine the morphological and molecular phylogenetic analyses of several bat trematodes from the genera Gyrabascus and Parabascus (Pleurogenidae): Gyrabascus amphoraeformis, Gyrabascus oppositus, Parabascus lepidotus, Parabascus duboisi, and Parabascus semisquamosus, of which G. amphoraeformis and G. oppositus are little known in European Russia. We made detailed morphological descriptions of these trematodes from several definitive hosts, analyzed morphometric features, and generated new partial sequences of the 28S rRNA gene. A broad variability of trematodes of the genera Gyrabascus and Parabascus was revealed both from various host species and from specimens of the same host species. We propose a new taxonomic key for the identification of the studied species. Certain host specificity of these trematodes was revealed.
Keywords: 28S rRNA; Gyrabascus; Microchiroptera; Parabascus; Trematoda; bats; molecular phylogeny; taxonomy.