Phylogenetic relationships of some species of the family Echinostomatidae Odner, 1910 (Trematoda), inferred from nuclear rDNA sequences and karyological analysis

Abstract

The family Echinostomatidae Looss, 1899 exhibits a substantial taxonomic diversity, morphological criteria adopted by different authors have resulted in its subdivision into an impressive number of subfamilies. The status of the subfamily Echinochasminae Odhner, 1910 was changed in various classifications. Genetic characteristics and phylogenetic analysis of four Echinostomatidae species – Echinochasmus sp., Echinochasmus coaxatus Dietz, 1909, Stephanoprora pseudoechinata (Olsson, 1876) and Echinoparyphium mordwilkoi Skrjabin, 1915 were obtained to understand well enough the homogeneity of the Echinochasminae and phylogenetic relationships within the Echinostomatidae. Chromosome set and nuclear rDNA (ITS2 and 28S) sequences of parthenites of Echinochasmus sp. were studied. The karyotype of this species (2n=20, one pair of large bi-armed chromosomes and others are smaller-sized, mainly one-armed, chromosomes) differed from that previously described for two other representatives of the Echinochasminae, Echinochasmus beleocephalus (von Linstow, 1893), 2n=14, and Episthmium bursicola (Creplin, 1937), 2n=18. In phylogenetic trees based on ITS2 and 28S datasets, a well-supported subclade with Echinochasmus sp. and Stephanoprora pseudoechinata clustered with one well-supported clade together with Echinochasmus japonicus Tanabe, 1926 (data only for 28S) and Echinochasmus coaxatus. These results supported close phylogenetic relationships between Echinochasmus Dietz, 1909 and Stephanoprora Odhner, 1902. Phylogenetic analysis revealed a clear separation of related species of Echinostomatoidea restricted to prosobranch snails as first intermediate hosts, from other species of Echinostomatidae and Psilostomidae, developing in Lymnaeoidea snails as first intermediate hosts. According to the data based on rDNA phylogeny, it was supposed that evolution of parasitic flukes linked with first intermediate hosts. Digeneans parasitizing prosobranch snails showed higher dynamic of karyotype evolution provided by different chromosomal rearrangements including Robertsonian translocations and pericentric inversions than more stable karyotype of digenean worms parasitizing lymnaeoid pulmonate snails.

Diversity of echinostomes (Digenea: Echinostomatidae) in their snail hosts at high latitudes

“…mordwilkoi from V . piscinalis in Lithuania was confirmed by DNA sequences [ 123 ]. Here, based on combined genetic and morphological characterisation, we report Echinoparyphium sp.…”

Molecular phylogeny and systematics of the Echinostomatoidea Looss, 1899 (Platyhelminthes: Digenea)

“…It is worth noting that the morphological description of the cercaria of Echinochasmus sp. VS-2012 (JQ088098) (Stanevičiūtė et al, 2008(Stanevičiūtė et al, , 2015 indicates a misidentification of…”

Echinostoma chankensis nom. nov., other Echinostoma spp. and Isthmiophora hortensis in East Asia: morphology, molecular data and phylogeny within Echinostomatidae

“…To find out whether trematodes, classified as cosmopolitans, are such or belong to different species, a comprehensive approach is necessary, including obtaining information on the life cycle and morphology of developmental stages (primarily cercariae and adults) as well as molecular data for the worms from the experiment. The greatest contribution to the study of echinostomatids, using an integrated approach, was made for worms circulating in Europe (Nasincova, 1991; Kostadinova et al ., 2000 a , 2000 b , 2003; Kostadinova and Gibson, 2002; Georgieva et al ., 2014; Faltynkova et al ., 2015; Hildebrand et al ., 2015; Staneviciute et al ., 2015). With regard to the echinostomatids of the East Asian region, for most worms, data were obtained separately either on the morphology of developmental stages or in the form of molecular data of adult worms from naturally infected animals (e.g.…”