Parasitological and molecular identification of cestode Bothriocephalus scorpii sensu stricto in the new host Chelidonichthys lucerna (L. 1758) (Triglidae, Scorpaenoidei) from the North Sea

Abstract

A specimen of female tub gurnard (Chelidonichthys lucerna) caught as bycatch in commercial saithe, Pollachius virens, fisheries near the Shetland Islands was identified as a new definitive host for the cestode Bothriocephalus scorpii (Bothriocephalidea) sensu stricto. It was also the first Cestoda species recorded in tub gurnard. However, as shown in our study, the identification of complex species such as Bothriocephalus scorpii based only on external characteristics had to be supplemented with molecular marker analysis to determine the taxonomic status of the specimen. Therefore, to successfully identify the parasite specimen, DNA was extracted from it, and a partial sequence of lsrDNA was amplified and the PCR product was subjected to 2 × 300 bp PE sequencing with 10,000× coverage on MiSeq. A BLAST search using the 346 bp sequence showed 100% similarity to the lsrDNA sequence of B. scorpii deposited in GenBank under accession number AF286942. Relatedness between the sequence of B. scorpii found in our study and the 20 most similar records from GenBank was identified using a phylogenetic tree constructed under maximum likelihood. Our study proves that next-generation sequencing of partial lsrDNA supplemented the morphological identification of the parasite specimen and can be applied in future parasitological studies.