Morphological and molecular characterization of plagiorchiid trematodes (Plagiorchis: Plagiorchiidae, Digenea) from bats with redescription of Plagiorchis mordovii Shaldybin, 1958

Abstract

Five Plagiorchis spp. parasitize bats in European Russia: Plagiorchis elegans, Plagiorchis koreanus, Plagiorchis mordovii, Plagiorchis muelleri, and Plagiorchis vespertilionis. Their identification is difficult due to a high morphological similarity. The morphological variability of these species is poorly studied. The taxonomic position of P. mordovii remains debatable. The purpose of our study was to analyse Plagiorchis spp. from European bats using a combination of morphological and molecular-phylogenetic approaches and to establish the taxonomic position of the problematic species P. mordovii.Plagiorchis spp. were shown to be variable morphologically and morphometrically both from various host species and from different specimens of the same species. We presented a new taxonomic key for identification of the Plagiorchis spp. from European bats, provided a complete description of Plagiorchis mordovii, and confirmed the validity and the generic affiliation of this species.

Molecular Diversity of the Genus Plagiorchis Lühe, 1899 in Snail Hosts of Central Europe with Evidence of New Lineages

“…Perhaps the most significant finding in our study, besides the record of two novel lineages, is the detection of P. vespertilionis from several snail hosts. Since no cox1 sequences were available in GenBank, our study benefited from the molecular data of Kirillova et al [48], allowing us to characterize one of the putative novel lineages as P. vespertilionis based on 28S sequences of adult worms. Thus, we were able to partially elucidate the life cycle of P. vespertilionis, as it was documented in three snail species, A. balthica, A. lagotis and R. auricularia, in our lakes.…”

“…Plagiorchis vespertilionis belongs to the 'Plagiorchis vespertilionis group', comprising also P. koreanus and P. muelleri, all of which have been confirmed molecularly as distinct species parasitizing bats in Europe [33]. The adults of the group are morphologically very similar [33,48], and their cercariae appear to be uniform to a certain extent, especially with regard to the high number of small and medium-sized lipid droplets (see Figure 5 and descriptions of live cercariae in the present study and those of P. koreanus and P. muelleri in Zikmundová et al [40] and Kudlai et al [6], respectively). Nevertheless, cercariae of P. vespertilionis are larger in almost all body parameters than cercariae of P. koreanus described by Zikmundová et al [40], but at the same time do not differ significantly from a single cercaria of P. muelleri described by Kudlai et al [6].…”

“…Cercariae of Plagiorchis, the free-living larvae emerging from a snail host, belong to the xiphidiocercariae morphotype, possessing a stylet to facilitate penetration into the next hosts, two suckers and a long, simple tail [46,47]. The distinguishing features of Plagiorchis species are inconspicuous and difficult to differentiate both in cercariae [6,40] and adults [33,48]. For example, the number and size of lipid droplets in the body parenchyma, the shape of the stylet, and body size can exhibit intraspecific variation [6,40], and some features, such as the presence of a slight base thickening on the stylet, can be very subtle and require a high level of morphological expertise.…”