Microwear patterns on the teeth of northern high latitude hadrosaurs with comments on microwear patterns in hadrosaurs as a function of latitude and seasonal ecological constraints
Anthony R. Fiorillo
Dental microwear studies have value in qualitatively addressing patterns of food use in both extinct and extant vertebrates. This study has examined dental microwear patterns on the teeth of Campanian/Maastrichtian hadrosaurs from northern Alaska to western Texas. The primary parameters examined were the incidence of pitting and the orientation of linear features on the occlusal surfaces of the teeth. The results of the examination have shown similar patterns of tooth wear independent of geographic location. Thus it may be that hadrosaurs all along western North America were consuming food items with similar hardness.
The dominant food consumed by hadrosaurs is considered to be conifers, although it is unlikely that conifers constituted the entire diet of the high latitude forms given the constraints imposed by a highly seasonal annual cycle. Further, given the similarity of food items consumed along such a large latitudinal gradient, combined with the deciduous nature of the food items in Alaska, it seems likely that northern hadrosaurs reduced their metabolic rates during the winter months, in a manner similar to many modern terrestrial Arctic vertebrates. This reduction in metabolic rate during the winter months may have been facilitated if these animals were inertial homeotherms (i.e., of a low surface: mass ratio) or ectotherms rather than full endotherms.
Anthony R. Fiorillo. Museum of Nature and Science, P.O. Box 151469, Dallas, TX 75315
Key words: hadrosaurs; Cretaceous; microwear; Alaska; food use; polar latitudes
PE Article Number:
Copyright: Society of
Vertebrate Paleontology November 2011
Submission: 15 June 2007. Acceptance: 11 March 2011