Gyrodactylus triglopsi n. sp. (Monogenea: Gyrodactylidae) from the Gills of Triglops nybelini Jensen, 1944 (Teleostei: Cottidae) in the Barents Sea

Abstract

<i>Introduction</i> - Monogeneans of the genus <i>Gyrodactylus</i> were found on the gills of specimens of the bigeye sculpin <i>Triglops nybelini</i> Jensen, 1944 caught by trawl in the Barents Sea in January–February 2016.<p>

<p><i>Methods</i> - Morphological preparations of the parasites were examined and photographed under a microscope at magnifcations of×100–1000 and morphometric analyses were carried out on 22 specimens using ImageJ2 software. Eight of the specimens used for the morphological comparisons were also subjected to molecular analyses by sequencing a region of the ribosomal DNA spanning partial 18S, the internal transcribed spacers 1 and 2 (ITS1 and 2), 5.8S and partial 28S and comparing this with other species through a BlastN-search in GenBank and through phylogenetic analyses.<p>

<p><i>Results</i> - The morphology of the species from <i>T. nybelini</i> was markedly diferent to that of any of other species of <i>Gyrodactylus</i>. It is characterized by having relatively long hamulus roots, a character that it shares with two other species described from marine sculpins (Cottidae); <i>G. armatus</i> and <i>G. maculosi</i>. It also has a narrow rectangular ventral bar membrane with a posterior notch which it shares with G. maculosi only. Compared with all the seven species from marine Cottidae described so far, it has the smallest opisthaptoral hard parts. A comparison of the internal transcribed spacer (ITS) rDNA sequence with available sequences in GenBank and a phylogenetic analyses also showed it to be highly divergent from other sequences. Therefore, a new species is proposed, <i>Gyrodactylus triglopsi</i> n. sp.<p>

<p><i>Conclusion</i> - Both the morphological and molecular analyses support the status of <i>G. triglopsi</i> as a new species. This is to our knowledge the frst species of <i>Gyrodactylus</i> described from <i>Triglops nybelini</i> and the description extends the list of <i>Gyrodactylus</i> species found on fsh in the Barents Sea to 17.