A comparative analysis of two Amur grayling species from the Thymallus Genus (Salmoniformes; Thymallidae) according to a number of osteological and morphological features in their zone of sympatry

Abstract

The results of the comparison of the Lower Amur grayling Thymallus tugarinae and the yellowspotted grayling T. flavomaculatus that were collected in the zone of their sympatry in the middle reaches of the Anuy River (the Lower Amur basin) for a number of osteological and morphological features are provided. The work was based on the analysis of X-ray images and a number of plastic features. Considerable differences were detected between the two species in the numbers of the bone elements of the axial skeleton. The differences in the number and topography of certain bone elements correlate with the morphological features of these species. The comparison results for certain features do not correspond with the literature data.