The karyotype of freshwater redclaw crayfish Cherax quadricarinatus (von Martens) was studied
by examining metaphase chromosome spreads from the testis tissues. A total of 79 mitotic
metaphases were examined and the diploid chromosome number ranged from 188 to 203 per
metaphase with a mode at 200, representing 25.8% of the metaphases. The number of bivalents
varied from 88 to 103 with a mode at 100, representing 54.4% of the 168 meiotic metaphases
observed. The number of diploid chromosomes (2n = 200) was confirmed by the modal haploid
chromosome number (n = 100) in the adult testis of this species. The karyotype consisted of 33
metacentric, 25 submetacentric, 14 subtelocentric and 28 telocentric chromosome pairs. The sex
chromosomes, if it exist in this species, were cytologically indistinguishable.
D 2004 Elsevier B.V. All rights reserved.