Fig. 4 in A Different Perspective on Sex Dimorphism in the Adult Hermann's Tortoise: Geometric Morphometry.

Fig. 4. Dorsal view of landmarks used for the plastron. A, Landmark points used on the photo. B, The differences between females and males are indicated by landmarks (MorphoJ). The round marks represent the female, and extensions from those marks indicate the direction and changes in the male turtles.