Enamel microstructure of Recent and fossil Canidae (Carnivora: Mammalia)

ABSTRACT

The tooth enamel of living and fossil Canidae has been studied to test the hypothesis that a special type of Hunter-Schreger bands (HSB), termed zigzag HSB, is associated with bone consumption. It is shown that in the enamel of Canidae, as in other Carnivora, three types of HSB occur: (1) undulating, (2) acute-angled, and (3) zigzag HSB. Mapping the occurrence of these different types on to the proposed phylogeny of the Canidae indicates that zigzag HSB were derived from undulating bands. Undulating HSB, which have a three-dimensional simple structure, are associated with an insectivorous to carnivorous diet, whereas zigzag HSB occur in taxa that consume bone. Complex three-dimensional zigzag HSB increase the resistance of enamel to formation and propagation of cracks under greater loading of the teeth during bone crushing.