No abstract

No abstract

Karyometrical analysis of conventional Giemsa-stained mitotic chromosomes of parthenitae of Sphaerostomum bramae (Trematoda: Opecoelidae) was carried out. The karyotype displays a typical ‘plagiorchiid’ pattern with 22 chromosomes in a diploid set including a first pair of large metacentric elements. Chromosomes with medially or submedially located centromeres prevail in the karyotype; only chromosomes 7 and 9 are subtelocentric. With the data now available, close karyological affinity was noted between S. bramae, the representative of the family Opecoelidae, and other karyologically studied species of some families in the order Plagiorchiiformes: Troglotrematidae, Plagiorchiidae, Prosthogonimidae, Lecithodendriidae and Telorchiidae.

Chromosomal complements of Posthodiplostomum cuticola and P. brevicaudatum were studied using the air-drying technique and Giemsa staining. The diploid chromosome number for these species was 2n =20. The structure of karyotype of P. cuticola was: lst-5thA + 6th-8th ST-SM + 9th SM + lOth SM-M. The haploid genome had a total length of 42.96 J.1m, chromosomes ranged in size from 2.06 J.1m to 7.23 J.1m. The structure of karyotype of P.brevicaudatum was: 1st, 4th, 8th ST + 2nd, 3rd, 5th, 6th A + 7th, lOth SM + 9th ST-SM. The total length of the haploid genome reached 39.46 J.1m , chromosomes ranged in size from 2.00 J.1m to 7.20 J.1m. The chromosomal sets of Posthodiplostomum spp. were compared with karyotypes of other studied Diplostomidae.

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 (1 st to 5 th ), two pairs of submeta-subtelocentric (6 th -7 th ), one submetacentric (9 th ) and two pairs of metacentric chromosomes (8 th , 10 th ). A supernumerary chromosome variation (presenceIabsence of B-chromosome) and occurrence of triploidy in one population of I. platycephalus are reported. In addition, the karyological analysis of Lithuanian population of l. variegatus was carried out. In the light of presented and previously obtained data comparative karyology of genus Ichthyocotylurus is discussed.