The karyological investigations of some types from Cobitoidea from river system Tigris and Euphrates

This study was carried out on the chromosomal features of samples belonging to Cobitis elazigensis Coad & Sarieyyupoglu, 1988; Oxynoemacheilus argyrogramma (Heckel 1846); Oxynoemacheilus frenatus (Heckel 1843); Oxynoemacheilus sp. And Turcinoemacheilus kosswigi Banarescu ve Nalbant, 1964 (Superfamilya: Cobitoidea) collected from Tigris and Euphrates River System by cytogenetic studies (karyotype, C-banding and nucleolus organizer region-NOR).The diploid chromosome number of Cobitis elazigensis from Cip Dam related Euphrates River System was to be 2n= 50, consisting of 9 pairs of meta-submetacentric, 16 pairs of acrocentric and NF=68. The C-positive heterochromatin was present in the centromeres of almost all chromosomes. Centromeric C-bands of uniarmed chromosomes were weaker and smaller in comparison with the of biarmed chromosomes. NOR was observed at a telomeric position on the short arms of one pair of the submetacentric chromosomes.Oxynoemacheilus argyrogramma specimens from Tigris River System has 2n = 50 and a karyotype composed of 22 pairs of meta-submetacentric, 3 pair of acrocentric chromosomes (NF=94). However, those of specimens from Euphrates River System has 2n = 50 and a karyotype composed of 21 pairs of meta-submetacentric, 4 pair of acrocentric chromosomes (NF=92). Almost all other biarrned and uniarmed elements of chromosome set had C-positive. Ag-NOR regions were: at a telomeric position on the longer arm of one pair of the biggest submetacentric chromosomes.The diploid chromosome number of Oxynoemacheilus frenatus from both Tigris and Euphrates River Systems were to be 2n= 50, consisting of 16 pairs of meta-submetacentric, 9 pairs of acrocentric and NF=82. The C-positive heterochromatin was present in the centromeres of almost all chromosomes. NOR was observed on the long arms of two pairs of medium sized acrocentric chromosomes.On the other hand, The diploid chromosome number of Oxynoemacheilus sp. from Kozluk Stream of Euphrates River System has 50 chromosomes and the karyotype comprised of 15 pairs of metacentric-submetacentric, 10 pairs of acrocentric chromosomes with the arm numbers 80. The C-positive heterochromatin was present in the centromeres of almost all chromosomes. NOR was observed on the long arms of two pairs of medium sized acrocentric chromosomes.The diploid chromosome number of Turcinoemacheilus kosswigi from River Tigris has 2n= 50 and the karyotype comprised of 4 pairs of metacentric 8 pairs of submetacentric-subtelocentric, 13 pairs of acrocentric chromosomes with the arm numbers 74.Sex chromosomes were morphologically undifferentiated in all samples investigated. This study may contribute to cytogenetic and taxonomy of Subfamily Cobitoidea.