Fig. 1

Diagrammatic illustration of the general morphology of the squamate naso-palatal complex. Transverse sections through the snout at the level of the VNO (a), the choanal groove (b) and the outer choana (c). Figs. a and b: Phyllodactylus, modified from [5]; c: Hemidactylus, modified from [13]. d Longitudinal cutaway through the snout of Lacerta at the level of the right choanal groove showing the nasal cavity from the medial side. e Ventral view of the palate of Gekko gecko. Figs. d and e: modified from [5]. * Note that drawings show different species. The levels of the sections (for a–c) and cutaway (for d) shown in e facilitate understanding a general squamate morphology, but may be inaccurate when considering the detailed anatomy of particular taxa. Abbreviations: a anterior, aos antorbital space, chf choanal fold, chg choanal groove, cmb cartilage of the mushroom body, dv duct of the VNO, ecc ectochoanal cartilage, ecs extraconchal space, ich inner choana, ict inner choanal tube, lcf lateral choanal fissure, ld lacrimal duct, lnc lateral nasal concha, lta lamina transversalis anterior, mb mushroom body, mnc main nasal cavity, mxf maxillary fold, och outer choana, oct outer choanal tube, pp premaxillary papilla, scf subconchal fold, Stt Stammteil, vc vomerine cushion, vch ventral channel, ves vestibulum, vf vomeronasal fenestra