Figure 6 in Variation in elasmoid fish scale patterns is informative with regard to taxon and swimming mode

Figure 6. Scaled body section of slices (in grey) in the different longitudinal (A, C, and P) and transversal zones (1, 2, and 3). Angles increase from the central areas to the extremes. The lower insets show the transformations between the overall scale consensus shape (reference) and the shapes represented by the extremes of principal component 1 (PC1) (targets; leftmost = -ve PC1 scores; rightmost = +ve PC1 scores; see Fig. 4), which broadly reflect anterior–posterior variation in scale shape.