Chromosomal characterisation of three dragonflies' species (Odonata: Anisoptera: Gomphidae).

Dragonflies of the family Gomphidae (order Odanata) possess characterstic club-like structure in the last segment of abdomen. Male germ cell chromosomes of Lamelligomphus biforceps, Nepogomphus walli and Onychogomphus grammicus of family Gomphidae were investigated, using carbolfuchsin staining, C-banding, silver nitrate staining and sequence specific staining. All the three possess chromosome complement 2n = 23, which is the type number of the family Gomphidae with XO/XX sex determining mechanism. Terminal C-bands are present on the autosomal bivalents, while bivalents show variation in distribution of NORs (Nuclear Organiser Regions). X chromosome is C- positive and NOR rich in all the species. All the autosomes show CMA₃ (Chromomycin A3) bright signals in Lamelligomphus biforceps, whereas bright DAPI (4′,6-diamidino-2-phenylindole) signals in Onychogomphus grammicus, and both DAPI and CMA₃ bright signals in Nepogomphus walli. The X chromosome of L. biforceps possesses DAPI bright signals, while it reveals both DAPI and CMA₃ bright signals in N. walli and O. grammicus. Cytogenetic analyses of all the species have been done for the first time. [ABSTRACT FROM AUTHOR]