PHYLOGENETIC AND INTRA-SPECIFIC VARIATIONS IN TOOTH SEQUENCE POLYMORPHISM

Abstract

This chapter reviews phylogenetic and intraspecific variations in tooth sequence polymorphism. The sequence of eruption of the permanent teeth shows a remarkable shift through the order primates. At one end, in the insectivores, the posterior or molar teeth add themselves to the dental arcade before the deciduous anterior teeth even begin replacement. At the other end, typified by the textbook European, the deciduous anterior teeth are largely replaced by their permanent successors before the second and third molar teeth extend the effective size of the dental arch. This distinction in eruption order between early primate and modern man is paralleled by a less dramatic but comparable difference between ape and man. The discovery of immature paleoanthropic hominids directed attention to their still-developing if fossilized teeth. There appeared to be a neat developmental difference that put paleoanthropic man in one eruption set and neanthropic man in another, except perhaps for the copper-age Greeks. But this neat differentiation between fossil and modern hominids based on the presumed order of eruption in a few juvenile fossil mandibles and the average age at eruption from norms for Europeans proved to be one of the credible but incorrect myths. In living apes, or preserved specimens, gingival eruption has been the point of record. Available data and data summarizations, thus, combine alveolar eruption, gingival eruption, estimates of eruption order based on the relative heights of the erupted teeth, and radiological assessments.