Variability and systematic status of Siberian spined loach Cobitis melanoleuca (Cypriniformes; Cobitoidei) in the Baikal region

Abstract

Siberian spined loach Cobitis melanoleuca (sensu lato) is distributed in the Northern Eurasia, and the Baikal region is the center of an areal of this species (or group of species). The present study analyzed the variability of exterior traits in eight populations of Siberian spined loach in the Baikal region (original data) and in the whole range (literature data). The results of the study have shown a high polymorphism of traits traditionally considered species-specific. It was found that populations of spined loaches inhabiting the Cisbaikalia are a mixture of phenotypes typical of Cobitis melanoleuca (sensu stricto), Cobitis granoei, and Cobitis olivai. It has been suggested that this may be caused either by the conspecificity of these taxa or by their hybridization. The refined data on nomenclature and diagnostic traits of taxa included in the synonymy of Cobitis melanoleuca (sensu lato) are presented in this study. It is suggested that at the current level of study of Siberian spined loach C. melanoleuca, it is reasonable to consider it as one polymorphic species, without division into vicariant forms.