VARIABILITY IN OXYGEN-ISOTOPE COMPOSITIONS OF HERBIVORE TEETH - REFLECTIONS OF SEASONALITY OR DEVELOPMENTAL PHYSIOLOGY

Oxygen isotope compositions of herbivore tooth enamel from two areas i n Kenya were measured using a laser fluorination approach. Isotope het erogeneity was found within four sets of teeth in the jaws of differen t individuals (similar to 2 parts per thousand), as well as within ind ividual teeth. The rear molar (M3) of a zebra shows a 1.4 parts per th ousand variability, whereas, the middle and rear molars (M2 and M3) of a gazelle show variations of 1.7 to 2.9 parts per thousand. The front molar (M1) of a gazelle is relatively homogeneous (similar to 0.25 pa rts per thousand). Compositional heterogeneities are spatially correla ted, and comparison to theoretical models suggests that they largely r eflect different times of tooth growth coupled with seasonal changes i n forage composition, rather than developmental physiology. Spatially- specific enamel analysis combined with knowledge of genus-specific die t, water turnover, and physiology allows paleoclimate seasonality to b e assessed. (C) 1998 Elsevier Science B.V. All rights reserved.