Figure 4: Diagrammatic representation of tooth development of four taxa depicting the evolution from a pointed piercing dentition to a flattened crushing one.
From: European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia
(a) Generalized stem neodiapsid showing the plesiomorphic condition of denticles on the palate. (b) Palatodonta bleekeri gen. et sp. nov., with a single row of pointed teeth on the palatine, maxilla and dentary. (c) The basal placodont Paraplacodus, with rounded teeth, more adapted for a crushing diet. (d) Typical dentition of Placodus and cyamodontoid placodonts, showing highly flattened and enlarged crushing teeth. Note that mode of tooth replacement is not known in Palatodonta. In Paraplacodus, vertical tooth replacement is inferred by presence of dentary replacement teeth in PIMUZ T2805. Abbreviations as in Fig. 1.
