Fig. 4.

Six geographic populations of Glandirana rugosa in Japan with their sex chromosome types. Each color in the map shows the distribution of each population. Filled and open square with rounded corners in the margin represent the homomorphic and heteromorphic sex chromosomes, respectively. Male and female heterogamety are depicted by green and purple of each square with rounded corners, respectively. The yellow area in the map represents the intermingling population between the Western Central Japan population (Neo-ZW) and the Eastern Central Japan population (XY).