Chromosome studies of Ichthyocotylurus platycephalus (Creplin, 1825) Odening 1969 with description of triploid variant and comparative karyology of the genus Ichthyocotylurus.

This paper reports the first karyological study of trematode Ichthyocotylurus platycephalus (Creplin, 1825) Odening 1969. Chromosome number and morphology were studied in somatic cells of parthenites from intermediate host--mollusc Valvata piscinalis using an air drying technique and Giemsa staining. The karyotype consisted of 20 chromosomes comprising five pairs of subtelo-acrocentric (1st to 5th), two pairs of submeta-subtelocentric (6th-7th), one submetacentric (9th) and two pairs of metacentric chromosomes (8th, 10th). A supernumerary chromosome variation (presence/absence of B-chromosome) and occurrence of triploidy in one population of I. platycephalus are reported. In addition, the karyological analysis of Lithuanian population of I. variegatus was carried out. In the light of presented and previously obtained data comparative karyology of genus Ichthyocotylurus is discussed.