New Data on the Morphology of Myoxocephalus scorpioides (Cottidae) from the Chaun Bay of the East Siberian Sea and Analysis of the Variability of Some Diagnostic Characters of the Species

This paper presents a morphological description of Myoxocephalus scorpioides from the Chaun Bay of the East Siberian Sea. A comparative analysis of the studied individuals with representatives of the species from the Bering Sea, as well as with the literature data on a combined sample of M. scorpioides from the Chukchi Sea and Bering Strait, has revealed a geographical variability of morphometric characters and a high degree of stability of a number of meristic characters (number of rays in the 1st dorsal fin and anal fin and total number of vertebrae). The significance of some taxonomic characters has been clarified. It is shown that characteristics such as the absence of postorbital and occipital tubercles, the presence of barbels in their place, the presence of bone plaques on the sides of the body, and the lengths of the upper and lower jaws, can be used for taxonomic purposes with high reliability.