Figures 17–18 in Reanalysis of Teruelius and Grosphus (Scorpiones Buthidae with descriptions of two new species

Figures 17–18. Morphometric analyses of spiracles. Figure 17. Bivariate logarithmic scatter plot of circularity vs. Feret's caliper ratio of spiracle IV aperture shapes in Grosphus (n = 37, 10 spp.), Teruelius (n = 45, 18 spp.) and outgroup taxa (n = 11, 7 spp.). Aperture defined as margin of opening of passage leading to atrium and book lung lamellae, excluding ridges and ornamentation. Figure 18. Elliptic Fourier Analysis (EFA) of spiracle aperture shapes of Fig. 17. Upper panel: bivariate scatter plot of principal component PC2 (11.63% of variance) vs. PC1 (30.32% of variance) extracted from PCA of up to 8th order harmonics (32 coefficients) of spiracle profiles. Profiles oriented with long axis horizontal, anterior on top, start point at top centroid. Lower panel: frequency distributions of Grosphus (cyan bars) and Teruelius (yellow bars) along PC1 axis. Color codes of symbols indicated in Fig. 16–17 legends.