PHYLOGENETIC CONSTRAINT OF THE RELATIONSHIP BETWEEN DENTAL MORPHOLOGY AND DIET IN EXTANT CARNIVORA

The relationship between dental morphology and diet is widely exploited by paleontologists to infer diet of extinct mammals. A variety of morphological proxies exist for the proportion of meat in the diet of carnivoran mammals; the most widely-used proxies are the proportion of the lower carnassial devoted to shearing function and the extent of post-carnassial molars. We examined the correlation between diet and three proxies (carnassial angle, trigonid ratio, and postcarnassial molar ratio) in the mammalian order Carnivora using both ordinary and phylogenetically-controlled statistics. While the dimensions of the carnassial and the postcarnassial molars strongly correlate with diet, a great deal of this correlation is explained by evolutionary history, such that the relationship between diet and dental morphology is barely significant for trigonid ratio and postcarnassial molar ratio and actually not significant for carnassial angle in phylogenetically-controlled analyses. This finding may result from the fact that both diet and dental morphology are constrained by evolutionary history; if, for example, diet is strongly constrained by evolutionary history, and dental morphology is functionally constrained by diet, a result such as we observed would be expected. However, our finding does emphasize the importance of considering the possibility of phylogenetic constraint in shaping the correlations that underlie proxies developed from living species. It is possible that the functional relationship on which the proxy depends is less important than the phylogenetic constraint that maintains the correlation, in which case caution should be used in interpreting the values for the proxy in groups not phylogenetically bracketed by the species used to establish the correlation between morphology and diet.