Fig. 1

Morphological diversity of avian and reptilian integumentary appendages. Scanning electron microscopy (SEM) was used to examine the morphological characteristics of avian and reptilian appendage types. The E14 chicken embryo (Gallus gallus) possesses feathers (A), scutate scales on the metatarsal shank and dorsal foot surface (B), and reticulate scales on ventral foot surface (C). The hatchling veiled chameleon (C. calyptratus) possesses bilateral scales on the dorsal and ventral foot surface, which bare morphological similarity to reticulate scales (D). The hatchling blue-headed anole (A. allisoni) (E) and the E46 bearded dragon (Pogona vitticeps) (F) possess large overlapping scales, more similar to avian scutate scales. Scale bar lengths are: A, Bi, Di, Dii, Ei, Eii, Fi, Fii = 125 µm, Ai, Aii = 50 µm, B, D, F = 500 µm, Bii, Ci = 75 µm, C, E = 250 µm, Cii = 25 µm