Identification of Cobitis from the Slovakian part of the Tisza basin

This study identifies of populations of the genus Cobitis from the Slovakian Tisza drainage area, using karyotype, enzyme electrophoresis and flow cytometry. Pure diploid populations of Cobitis elongatoides were found in drainage basins of the Hornád, Slaná and Bodva rivers (5 populations). Species identifity was proven by analysis of genome and allelic composition. A large number of males was in these populations (42.5-60%). The drainage basin of the Bodrog river (3 populations), harbored so-called hybrid diploid-polyploid complexes with basic composition C. 2 elongatoides x 1 tanaitica. If diploid specimens were found, they belonged to C. elongatoides. Apart from triploids, diploids were rarely found in the Ondava and Latorica rivers. In the Bodrog River, tetraploids (C. 3 elongatoides x 1 tanaitica were seldom found beside triploid and diploid individuals. The percentage of males in hybrid complexes was very low (up to 16.2 %).