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. Author manuscript; available in PMC: 2017 Feb 15.
Published in final edited form as: J Comp Neurol. 2015 Jun 11;524(3):471–495. doi: 10.1002/cne.23802

Figure 7.

Figure 7

Stages in the evolution of mammalian secondary palate and the ortho-retronasal olfaction duality. (A) Eusthenopteron, a stem-tetrapod; (B) Seymouria, a stem amniote; (C) Dimetrodon, a basal synapsid; (D) Syodon, a more derived non-cynodontian synapsid; (E) Procynosuchus, the basal-most cynodont with an incipient secondary palate; (F) Thrinaxodon, an early cynodont with a complete secondary palate; (G) Kayentatherium, a basal mammaliamorph with a complex dentition; (H) Morganucodon, a basal mammaliaform, with secondary palate extending to back of tooth row; (I) Didelphis, with secondary extending behind tooth row. Abbreviations: ch – choana; max – maxilla; pal – palatine; pmx - premaxilla; pt – pterygoid; vo – vomer.