Male meiotic chromosomes of Rhaphidosoma paganicum sp. nov., n=12AA+X1X2X3Y (2n=24A+ X1X2X3Y) A first prophase, early condensation stage (chromosomes X1X2X3 are located in a train and the Y is located slightly away from them) B, C metaphase I (sex chromosomes X1X2X3Y are lying side by side inside the ring formed by autosomal bivalents) D hybridisation signals of 18S rDNA-FISH (green) and (TTAGG)n-FISH (red) are visible on Y and one of the X-chromosomes (small green signals are also seen in some autosomal bivalents, but they proved to be not specific), and on both ends of each chromosome, respectively; Inset, Y and an X-chromosome with 18S rDNA signals E (TTAGG)n-FISH-signals are visible in spermatids. Scale bar: 10 μm.