Comparative Karyotype Analysis Of Slugs Of The Genus Arion (Gastropoda, Pulmonata, Arionidae)

Karyotypes of four species of the genus Arion were investigated, namely, A. distinctus (2n = 48m + 8sm = 56; FN = 112), A. lusitanicus s. l. (2n = 4 4m + 6 sm + 2st = 52; FN = 104), A. fuscus (n = 26, 2n = 52, FN = 104) and A. fasciatus (n = 29, 2n = 58, FN = 116). The karyotype of A. lusitanicus s. l. was identical to those of A. fuscus, A. ater and A. rufus. The karyotype of A. fasciatus in the haploid number of chromosomes is identical to another close species — A. circumscriptus (n = 29) from the United Kingdom. The identical number of chromosomes in species of the subgenus Arion (A. lusitanicus s. l., A. ater, A. rufus) and species of the subgenus Mesarion (A. fuscus) (n = 26) may be a reason for their merging.