Dental morphology of the cannibal morph in the tiger salamander, Ambystoma tigrinum

Abstract

AbstractCannibalistic behavior is accompanied by a robust dental and skeletal polymorphism in cannibal tiger salamanders, Ambystoma tigrinum. This study describes the dental polymorphism in terms of hypertrophy, recurvature, and surface detail as revealed by scanning electron microscopy. Vomerine and dentary teeth in cannibals are longer than those of non-cannibals of the same head size. While cannibals exhibit recurved teeth on each dentigerous bone, straight peg-like teeth appear occasionally. Conversely, isolated recurved teeth may be present in non-cannibals. No consistent differences between cannibal and noncannibal teeth with respect to the surface geography of the pedicel, shaft, or pedicel shaft junction were observed. Hypertrophy of the horizontally ankylosed vomerine teeth is associated with a distortion of the underlying vomer. This suggests that alterations in odontogenesis may effect changes in the morphogenesis of underlying dentigerous bones. Differential rates of development (heterochrony) between the skull (dentigerous bones) and the dentition may be a characteristic feature in the evolution of cranial morphology in cannibal tiger salamanders.