Karyotypes and sex chromosome diversity in three stonefly species (Plecoptera: Perlodidae, Perlidae) from Siberia

The current paper focuses on studying morphology of the autosomes and sex chromosomes in karyotypes of three stonefly species from Siberia. We provide new cytogenetic data for species from Perlodidae (Arcynopteryx dichroa (McLachlan, 1872), Megarcys ochracea (Klapálek, 1912)) and Perlidae (Kamimuria exilis (McLachlan, 1872)) families. The karyotype of male and female of A. dichroa consists of 13 pairs of chromosomes (2n♂♀=26). The sex determination mechanism in A. dichroa is XY/XX. The male M. ochracea consists of 8 pairs of chromosomes (2n♂=16). The karyotype of females M. ochracea consists of 9 pairs of chromosomes (2n♀=18). The sex determination mechanism in M. ochracea is ♂Х1Х2/♀Х1Х1Х2Х2. The male K. exilis karyotype consists of 10 pairs of autosomes and one unpaired X-chromosome (2n♂=21, the determination of sex is X0). The karyotype of female K. exilis consists of 11 pairs of chromosomes (2n♀=22, the determination of sex is XX). All chromosomes of the studied stonefly species are metacentric or submetacentric. Pericentromeric C-bands were revealed for all chromosomes of K. exilis. Additionally, their mid-size submetacentric chromosomes possesses small telomeric C-bands in the long arms. The submetacentric X-chromosomes of the male and female K. exilis also have small intercalary C-bands proximally in the long arm (XR). New data on Plecoptera chromosomes confirm the unusual diversity of karyotypes of these insects in the Polyneoptera cohort.