Description and Phylogenetic Relationships of Pojmanskatrema balcanica n. gen., n. sp. (Digenea: Dicrocoeliidae) from the Eurasian Water Shrew Neomys fodiens (Mammalia: Soricidae) in Bulgaria

Phylogenetic interrelationships of 32 species belonging to 18 genera and four families of the superfamily Microphalloidea were studied using partial sequences of nuclear lsrDNA analysed by Bayesian inference and maximum parsimony. The resulting trees were well resolved at most nodes and demonstrated that the Microphalloidea, as represented by the present data-set, consists of three main clades corresponding to the families Lecithodendriidae, Microphallidae and Pleurogenidae + Prosthogonimidae. Interrelationships of taxa within each clade are considered; as a result of analysis of molecular and morphological data, Floridatrema Kinsella & Deblock, 1994 is synonymised with Maritrema Nicoll, 1907, Candidotrema Dollfus, 1951 with Pleurogenes Looss, 1896, and Schistogonimus Lühe, 1909 with Prosthogonimus Lühe, 1899. The taxonomic value of some morphological features, used traditionally for the differentiation of genera within the Lecithodendriidae and Prosthogonimidae, is reconsidered. Previous systematic schemes are discussed from the viewpoint of present results, and perspectives of future studies are outlined.

The genus Brachylecithum was for the first time subject to molecular taxonomic phylogenetic analysis in order to ascertain relationships among its component taxa. We used two markers—the nuclear ribosomal 28S ribosomal DNA (rDNA) gene and the mitochondrial cox1 gene, for six species of the genus; 11 sequences of partial 28S rDNA and partial cox1 were obtained from adult B. capilliformis, B. glareoli, B. kakea, B. laniicola, B. lobatum, and B. strigis, and from larval stages obtained from snails of the genus Cepaea. We propose to synonymize B. strigis with B. lobatum, while the genetic differences in the 28S rDNA gene and mitochondrial cox1 gene confirm the species status of B. capilliformis and indicate a distinct group within Brachylecithum, including B. kakea and B. laniicola. Cercarial and metacercarial isolates from the snails showed 100 % similarity to B. lobatum; thus, it is the first record of Cepaea snails as intermediate hosts of this species and the first report on life cycle abbreviation within the Dicrocoeliidae.

Lyperosomum sarothrurae Baer, 1959 is a rare dicrocoeliid described based on a single specimen from Belgian Congo, now Democratic Republic of the Congo, and never reported again. The original description lacked several important details of the species morphology. This work provides morphological redescription of Lyp. sarothrurae based on specimens from Kibale National Park, Uganda which is about 200 kilometres from the type locality. Results of re-examination of the holotype are also provided. Morphology of Lyp. sarothrurae shows some characteristics intermediate between those of the species rich genus Lyperosomum Looss, 1899 and Megacetabulum Oshmarin, 1964 that includes only 3 species. Due to the lack of clear morphological differences between the two genera, Megacetabulum is considered here as a junior synonym of Lyperosomum. Molecular phylogenetic analysis including Lyp. sarothrurae and all currently available partial sequences of the nuclear ribosomal 28S RNA gene of dicrocoeliid species is also included and its results are discussed.