FIGURE 4 in Operculum shape variation in Theodoxus Montfort, 1810 (Gastropoda: Neritidae)

FIGURE 4. Canonical Variate Analysis (CVA) showing operculum shape differences among populations of three Theodoxus species in the space of the first two CV axes covering 79.09% of the total sample variability (CV1 56.86% and CV2 22.23%). Abbrs. as in Table 1. The pattern of operculum shape differences among populations of three Theodoxus species corresponding to the first two CV axes is shown on a thin plate spline deformation grids. The average positions of the landmarks are linked with vectors pointing in the direction of shape changes along the axes.