Toggle Main Menu Toggle Search

Open Access padlockePrints

Enamel extension rate patterns in modern human teeth: Two approaches designed to establish an integrated comparative context for fossil primates

Lookup NU author(s): Dr Don Reid


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Enamel extension rates (EERs), the rates at which ameloblasts differentiate, determine how fast tooth crowns grow in height. Studies of fossil primate (including hominin) enamel microstructure usually focus on species differences in enamel formation time, but they have also begun to address species-level variation in enamel extension rates. To improve our ability to compare EERs among primate species, a better understanding how EERs vary within species is necessary. Using a large and diverse modern human histological sample, we find that initial EERs and patterns of EER change along the enamel-dentine junction (EDJ) vary in relation to EDJ length. We also find that enamel formation time varies in relation to EDJ length, but that it does so independently of initial EERs. These results suggest that EDJ length variation within a species sample can affect interspecific comparisons not only of EERs but also of enamel formation times. Additionally, these results lend within-species support to the hypothesis, based on comparisons among hominin species, that EERs and crown formation times can vary independently (Dean, 2009). In a second approach, we analyzed EER changes specifically in the lateral enamel of two modern human population samples as these changes relate to the distribution of perikymata. As surface manifestations of internal enamel growth increments, perikymata provide a valuable source of information about enamel growth in fossils. We find that EER declines in the lateral enamel are associated with an increase in perikymata density from first to last-formed lateral enamel. Moreover, variation in the extent of EER decline among individuals is associated with variation in the distribution of perikymata along their enamel surfaces. These latter findings suggest that the distribution of perikymata on the enamel surface provides information about rates of EER decline in lateral enamel, at least in modern humans. (C) 2012 Elsevier Ltd. All rights reserved.

Publication metadata

Author(s): Guatelli-Steinberg D, Floyd BA, Dean MC, Reid DJ

Publication type: Article

Publication status: Published

Journal: Journal of Human Evolution

Year: 2012

Volume: 63

Issue: 3

Pages: 475-486

Print publication date: 01/09/2012

ISSN (print): 0047-2484

ISSN (electronic): 1095-8606

Publisher: Academic Press


DOI: 10.1016/j.jhevol.2012.05.006


Altmetrics provided by Altmetric