Cytogenetic report on Cordulegaster brevistigma and Watanabeopetalia atkinsoni (Odonata: Cordulegastridae, Chlorogomphidae)

摘要

Live adult male specimens of C. brevistigma and W. atkinsoni have been collected from Shimla, Himachal Pradesh (India). Male germ cell chromosomes of the species are described on the basis of conventional staining, C-banding, silver nitrate staining and sequence specific staining. Both the species possesses 2n = 25m, as a diploid chromosome number and XO (male)/XX (female) type sex determination. In both the species, dark terminal C-bands are present on all the autosomal bivalents and X chromosome is C-positive throughout the length. Terminal light/dark NORs (Nucleolar Organizer Regions) are present on all autosomal bivalents, while X chromosome also possesses terminal NORs. During sequence specific staining, all the autosomal bivalents show prominent terminal DAPI (4',6-diamidino-2-phenylindole) and CMA(3) (Chromomycin A) bright regions and X chromosome also possesses both DAPI and CMA(3) signals. In addition, a brief review of the size of X element in the allied families Cordulegastridae, Corduliidae and Macromiidae is given.