Tooth Eruption Sequences in Cervids and the Effect of Morphology,Life History,and Phylogeny

Tooth eruption sequences vary in a non-random way among mammalian species. Several variables have been linked to this, including tooth and jaw shape, adaptations to diet, and food processing. Likewise, changes in eruption patterns correlate with the speed of postnatal growth in some groups, the Schultz’s Rule pattern. Here, the eruption pattern of the permanent dentition in lower jaws from different cervid species have been investigated to discern the effect of these factors and phylogeny as well as to reconstruct the ancestral tooth eruption sequence of cervids. In ruminants, the different patterns of emergence of permanent teeth seem to be best explained by phylogeny. The degree of hypsodonty, age of first molar eruption, and life history parameters such as longevity and age of female sexual maturity do not explain the observed sequential differences in eruption patterns. The Parsimov-based analysis for the ancestral state resulted in a tooth eruption sequence of m1 – m2 – i1 – i2 – i3 – c – m3 – (ppp) for Cervidae; a pattern recorded in Odocoileus, Capreolus, and Hydropotes. The eruption pattern of Caenomeryx filholi, from the Oligocene of Gaimersheim, is identical to the result of the Parsimov-based analysis except for the presence of a first premolar, a tooth lost in cervids.