Genetic Differentiation of the Fourhorn Sculpin <i>Myoxocephalus quadricornis</i> (Linnaeus, 1758) and Its Position in the Tribe Myoxocephalini Taranetz (Cottidae: Myoxocephalinae)

Abstract

A molecular genetic and karyological study of the fourhorn sculpin Myoxocephalus quadricornis (Linnaeus, 1758) was carried out. The karyotype was studied for the first time and the results of Ag-staining of the chromosomes of specimens of the species from the East Siberian Sea are presented. The karyotype of M. quadricornis is stable, contains 32 (10 metacentrics, 2 submetacentrics, 20 subtelocentrics) chromosomes, the number of chromosome arms is 44. Nucleolar organizers were found in the telomeric regions of the short arms of two homologous medium-sized subtelocentrics. Variability in the number of nucleolarforming chromosomes and stained blocks of nucleolar organizers was found. Common features in the chromosome sets of M. quadricornis and Megalocottus platycephalus indicate their greater similarity compared to species of the genus Myoxocephalus. The results of the karyological analysis are consistent with the molecular genetic data about the sister relationships between M. quadricornis and Megalocottus platycephalus. A complex of karyological and molecular-genetic features has been identified that allow one to reliably distinguish M. quadricornis from species of the tribe Myoxocephalini and indicate the need for its removal from the genus Myoxocephalus.