Phylogenetic relationships within Dicrocoeliidae (Platyhelminthes: Digenea) from birds from the Czech Republic using partial 28S rDNA sequences

Abstract

Partial (D1-D3) 28S rRNA gene sequences from 16 isolates of digenean parasites of the family Dicrocoeliidae recovered from 16 bird species from the Czech Republic were used for phylogenetic reconstruction. Comparison with sequences available from GenBank suggests that the genus Brachylecithum is paraphyletic, requiring further validation and possible systematic revision. Although partial 28S rDNA is relatively conserved, analyses suggest that the following taxa are synonymous: Lutztrema attenuatum = L. monenteron = L. microstomum, Brachylecithum lobatum = B. glareoli. Zonorchis petiolatus is reassigned back to the genus Lyperosomum with L. collurionis as a junior synonym. The study revealed how complicated the systematics of the family Dicrocoeliidae is currently. The morphology of the group is variable, and the current distinguishing characters at species and even generic level are not sufficiently distinctive; it is difficult to identify the specimens correctly and identification of GenBank isolates is not reliable. Extensive sampling of isolates for both molecular and morphological studies is necessary to resolve the relationships within the family.

Molecular phylogenetics and mitogenomics of three avian dicrocoeliids (Digenea: Dicrocoeliidae) and comparison with mammalian dicrocoeliids

“…and Brachylecithum sp. was consistent with their respective placement in the present as well as in previous phylogenetic analyses based on 28S rDNA sequences [1,15]. The tree also showed that the family Paragonimidae (represented by Paragonimus spp.)…”

“…An approximately 1300 bp long fragment at the 5′-end of the 28S gene of three avian dicrocoeliid species was amplified, as described in previous studies [1,15] using the primers LSU5 and 1500R [12,25] with an annealing temperature of 55 °C. For L. longicauda, DNA of two specimens (one from each host species) was used for the amplification of 28S gene in order to ensure that different isolates of the same species are identical.…”

“…were aligned with the complete mt genome of D. chinensis (GenBank: KF318786) while L. longicauda mtDNA was aligned with that of E. pancreaticum (GenBank: KP241855) using MAFFT Ver 7.122 [32] to determine genome organization and approximate gene boundaries. The selection of reference mitogenomes was based on the published phylogenetic relationships among dicrocoeliids [1,15]. Protein-coding genes (PCGs) and the two mt ribosomal RNAs (rrnL and rrnS) were identified via comparison with homologs using MAFFT Ver 7.122.…”

“…Until recently, molecular phylogenetic studies included only a few representatives of the Dicrocoeliidae [11,12], although the situation has been changing lately with a greater number of dicrocoeliid taxa being included in such analyses [1,7,10,[13][14][15]]. Among other systematic and nomenclatural changes, the molecular results have demonstrated the non-monophyletic nature of the majority of dicrocoeliid subfamilies, which resulted in the abandonment of the subfamily-based structure of the family [1].…”

“…(present study) appeared close (bpp = 0.96) to the clade containing species of Dicrocoelium and Brachydistomum and was not closely related to the remaining members of Brachylecithum in the tree, namely the clades B. lobatum Railliet, 1900 + B. capilliformis Oshmarin, 1952 and B. kakea Bhalerao, 1926 + B. laniicola Layman, 1926. Recent studies documented the paraphyletic nature of the genus Brachylecithum[1,15]. Tkach et al[1] suggested that B. grummti likely represents a separate genus, but underlined that formally establishing this new genus requires a thorough additional morphological analysis.…”