Examples of Gampsocleis species with 2n = 31 chromosomes (male): G. s. sedakovii (a, c–e) and G. ussuriensis (b) studied using different techniques: FISH with both 18S rDNA (green) and telomeric TTAGG (red) probes (a) in diakinesis revealed a single rDNA locus located distally on the 6th bivalent (white arrow) and one active NOR visualized by AgNO3 staining (b) in diplotene (black arrow). C-banding (c) as well as fluorochrome staining of heterochromatin with DAPI (blue) and CMA3 (green) bands in diakinesis (d and e, respectively); black arrows indicate a C-band, and white arrows indicate very weak DAPI+ and bright CMA3+ signals located in a distal region on the 6th bivalent. C (a–c), centromere; X (c–e), sex chromosome. Scale bar: 10 µm.