Karyotype of an avian schistosome Trichobilharzia szidati (Digenea: Schistosomatidae).

Somatic chromosomes of Trichobilharzia szidati Neuhaus, 1952 are described from larval stages dissected from snails, air-dried on slides and stained with Giemsa and C-banding technique, used for the first time in Trichobilharzia sp. The karyotype consisted of 7 autosomal pairs and 1 pair of sex chromosomes, ZZ in the male and ZW in the female, where Z and W chromosomes are of different sizes and both are classified as submetacentric. C-banding aided in identification of chromosomes Nos 4, satellited 6 and 8. No heterochromatin was observed in the W chromosome. The results were not in agreement with those previously reported and represent new findings. The possible explanation for this fact is given.