Comparative karyological analysis of three species of Bothriocephalus Rudolphi 1808 (Cestoda:Pseudophyllidea) from Schizothorax species of Kashmir valley.

Karyotypes of three species of Bothriocephalus were studied using conventional Giemsa staining and comparative karyometric analysis. Bothriocephalus claviceps and Bothriocephalus gregarius showed a karyotype with 2n = 14 chromosomes. All chromosomes of B. claviceps were biarmed, metacentric or meta-submetacentric. The two first pairs of homologues were markedly larger than the remaining elements and represented 48.62 % of the total chromosome length. The karyotype of B. gregarius had similar metric values for the chromosomes, but clearly differed in the chromosome morphology of pairs 5, 6 and 7, which had terminally located centromeres. The diploid number 2n = 12 was found in B. scorpii. The karyotype consists of five pairs of metacentric and one pair of submeta-metacentric chromosomes. The possible pathways of karyotype evolution within Bothriocephalus spp. and their phylogenetic relations with the other karyologically studied groups in the order Pseudophyllidea are discussed.