Evaluation of Differences between the Baltic Triglopsis quadricornis and White Sea Triglopsis sp. Using Morphological and Genetic Data

Abstract

According to the modern fish system, one species of fourhorn sculpin Triglopsis quadricornis lives in the Baltic Sea and Arctic waters. In the present study, sculpins from the Baltic and White Seas were studied using different methods: morphological analysis to establish patterns of the seismosensory system, tomography for the study of cranial bones, X-ray imaging for the study of the axial skeleton, as well as phylogenetic analysis of two mtDNA markers (control region and CO1) and one nDNA marker (RAG1). The results obtained by these methods were used to prove the existence of two species: T. quadricornis in the Baltic Sea and Triglopsis sp. in the White Sea. These species differ significantly in the unique shape and size of the bony outgrowths on the head, as well as in the number of bony plates on the body. Genetic differences between the species were expressed in the formation of T. quadricornis and Triglopsis sp. independent clusters on Bayesian phylogenetic trees reconstructed based on the sequences of the mtDNA control region and RAG1.