Fig. 4 in Variation in premaxillary tooth count and a developmental abnormality in a tyrannosaurid dinosaur

Fig. 4. Hypothetical zones of inhibition during premaxillary odontogenesis in tyrannosaurids. The outline represents a tyrannosaurid premaxilla in posteromedial view. A. A normal four−toothed premaxilla of a tyrannosaurid. B. TMP 2007.20.124 with only three premaxillary teeth. A zone of inhibition is a third larger in TMP 2007.20.124 than in a normal tyrannosaurid premaxilla, excluding the fourth tooth position from the alveolar margin.