Patterns and rates of enamel growth in the molar teeth of early hominids

Abstract

A recent study1 of the surface manifestation of incremental lines associated with enamel formation suggested that the crowns of early hominid incisor teeth were formed more rapidly than those of modern humans. In the absence of comparative data, the authors were forced to assume that enamel increments in fossil teeth were similar to those in modern humans. We have used evidence from the fractured surfaces of molar teeth to deduce estimates for both long- and short-period incremental growth markers within enamel in east African 'robust' australopithecine and early Homo teeth. We conclude that in these early hominids, crown formation times in posterior teeth, particularly in the large thick enamelled2 molar teeth of the east African 'robust' australopithecines, were shorter than those of modern humans. This evidence, considered together with data on crown and root formation times in modern apes3, suggests that the posterior teeth in these hominids both formed and erupted more rapidly than those of modern man. These results have implications for attempts to assess dental and skeletal maturity in hominids.