OSTEOLOGICAL CHARACTERIZATION OF FOUR SPECIES OF THE GENERA GOBIO AND ROMANOGOBIO WITH SOME REMARKS TO THE STATUS OF THE FORMER SUBGENUS RHEOGOBIO

Purpose. The aim of this work is to clarify the matter of suitability of current Gobioninae systematics, where Rheogobio is used as a synonym of Romanogobio or as a separate taxon by comparing four species of the genera Gobio and Romanogobio on the basis of osteological data and the structure of swimming bladder. Methodology. Four gudgeon species were examined based on the structure of axial skeleton and cranium. Osteological specimens were prepared after cleaning and staining with alizarin red S. Measurements were performed with ScopePhoto using DCM 500 digital camera. Calculations were performed using Statistica 8.0. For determination differences between species we used Student’s t-test and discriminant analysis. Drawings were made with CorelDRAW X5. Findings. R. uranoscopus is a specific species, swimming bladder of which reduced and its size is on average 10,6 % of SL, while in other gudgeons it reaches 21,0 to 31,8 % of SL. It may be an adaptation for occupying sites with high velocity, where it concentrates. Mahalanobis distance clearly demonstrates the difference of R. uranoscopus from other investigated species, the most similar species to R. uranoscopus by a complex of osteological data is R. kesslerii the least similar is G. carpathicus. According to discriminant analysis, R. uranoscopus is distinctly different from the genera Romanogobio and Gobio. The structure of separate elements of cranium, number of vertebrae and pectoral girdle bones also shows high distinction of R. uranoscopus from other species. Originality. Originality of this work is a new look on the systematic status of the subgenera Rheogobio based on osteological and other data. Practical value. Practical value of this work is an clarification of systematic status of the subgenera Rheogobio for agreement of nature protection documentation for avoiding different interpretations of the systematic status of species belonging to these subgenera.