engleski

Phylogeny and genetic variability of Rotifer’s closest relatives Acanthocephala: an example from Croatia

Acanthocephala or thorny headed worms is a group of obligatory endoparasites of Mandibulata and Gnathostomata which together with Rotifera form a monophyletic group referred to as Syndermata. Despite their close phylogenetic relationships, different lifestyles have led to different morphological and physiological characteristics of these two phyla. Although Acanthocephala is a relatively homogeneous group of parasites, considerable intraspecific variation within species can be observed. Here we present up-to-date status of phylogeny of acanthocephalans found in the freshwater fish in Croatia, including both the widespread species with broad range of hosts (e.g. Pomphorhynchus laevis) as well as the species confined to limited geographic areas with strong host specificity (e.g. Dentitruncus truttae). The sequences of three genes evolving at different rates (18S rDNA gene, COI gene and ITS region) were analysed in order to gain molecular insights into their phylogeny and genetic variability. 18S rDNA was useful for determination of the phylogenetic position of understudied (e.g. D. truttae) or not morphologically precisely identified acanthocephalans (Echinorhynchus sp.), but was non-informative for intrapopulation variability detection. For the most examined acanthocephalans the genetic variability of COI marker was low (≤1%) while the highest values were observed for the sister species of the genus Pomphorhynchus (0-10.3%). The similar results were obtained for the genetic variability of ITS region, with the highest values observed within Pomphorhynchus species (0-11.3%). Our results are important not just for further phylogeographic studies but also for precise identification of acanthocephalan genotypes which can serve as bioindicators in freshwater ecosystems contamination studies.

Pomphorhynchus laevis ; Dentitruncus truttae ; thorny headed worms

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