Figure 6
From: Avian tail ontogeny, pygostyle formation, and interpretation of juvenile Mesozoic specimens
Unfused juvenile pygostyles in extant and Cretaceous birds. White arrows indicate intervertebral spaces (empty arrowhead indicates possible intervertebral space); white bars indicate linear extent of pygostyles; all pygostyles distal to the left, dorsal to the top. (A) 5.5 month old emu pygostyle, microCT mid-sagittal view. (A′) Adult emu pygostyle. (B) Juvenile mallard duck distal tail, microCT mid-sagittal view. (B′) Adult mallard duck distal tail. (C) Juvenile Wilson’s snipe distal tail, microCT sagittal view. (C′) Adult Wilson’s snipe distal tail. (D) Juvenile Archaeorhynchus IVPP 17075. (E) Juvenile enantiornithine, IVPP 15664.
