The karyotype of R. sinicus

was 2n = 36, FN = 60 (Fig. 3), consisting of 13 large-to-small metacentric or submetacentric pairs and four medium-sized to small acrocentric pairs of autosomes, a medium-sized subtelocentric X chromosome, and a small subtelocentric Y chromosome. This species had a prominent secondary constriction involving one pair of medium-sized acrocentric chromosomes. The karyotype of R. sinicus from Hainan Island (2n = 36, FN = 60) does not differ from conspecific populations in the Chinese provinces of Anhui [6] (reported as R. rouxii sinicus), Sichuan [14], and Guangdong [15] in conventional karyotype and that from "south-western China" also in G-banding pattern [17], but does differ from the 2n = 56, FN = 60 karyotype of R. rouxii reported from India and Sri Lanka [31]. These karyological differences between R. sinicus and R. rouxii support the view that these two taxonomically confused taxa both represent distinct species, as previously proposed [14, 15, 26].