Fig. 12

The outer choanal tube and choanal groove at stages 18 and 19 of the brown anole based on 3D reconstructions (A, A’) and transverse histological sections at the approximated levels shown in Fig. 12A’ (B, C). A Ventral view of the palate; stage 18. A’ Ventral view of the palate; stage 19. B Section through the closed choanal groove; stage 19. C Section at the level of the outer choana; stage 19. Abbreviations: a anterior, chf choanal fold, chg choanal groove, ecc ectochoanal cartilage, ich inner choana, ict inner choanal tube, lcf lateral choanal fissure, ld lacrimal duct, och outer choana, ochg opening of the choanal groove, oct outer choanal tube, old opening of the lacrimal duct on the palate, pp premaxillary papilla, scf subconchal fold, Stt Stammteil, vc vomerine cushion, vc/chf fusion of the vomerine cushion with the choanal fold, vf vomeronasal fenestra. Red star posterior expansion of the lacrimal duct rostral plate, white arrows range of the closed choanal groove. Colours of 3D structures as in Fig. 9. Scale bars 350 μm (A, A’), 50 μm (B), 100 μm (C)