Figure 8. A in A standardized terminology of spines in the order Siluriformes (Actinopterygii: Ostariophysi)

Figure 8. A, right pectoral-fin spine in dorsal view showing retrorse (posterior margin, above) and antrorse (anterior margin, below) ornaments. B, detail of (A) (stippled green box) showing the definition of ornament orientation as a relationship between the proximal (π) and the distal (δ) angles with respect to the main axis of the ornament. C, left pectoral-fin spine in dorsal view presenting concavity as a complementary property of ornaments that reference the proximal or distal margin of it. D, detail of (C) (stippled green box) indicating concavity on the proximal margin of the ornament which is highlighted in green outline. Scale bar in (A) represents 5 mm, and 2 mm in (C); (A, B) Pterodoras granulosus, MZUSP 91655; (C, D) Bunocephalus coracoideus, MZUSP 103254.