On the occurrence of exceptionally large teeth of Troodon (Dinosauria: Saurischia) from the Late Cretaceous of northern Alaska

Exceptionally large teeth attributable to the theropod genus Troodon are abundant in Upper Cretaceous rocks (Campanian-Maastrichtian) of northern Alaska. The dominance of low-angle light in this Cretaceous high-latitude environment seems to have selected for an abundance of Troodon. The population of these Alaskan specimens-morphologically the same as teeth attributable to this taxon in other regions-show a mean approximately twice the size of those found in such southern latitudes as southern Alberta and Montana. Microwear patterns on the teeth of this taxon in Alaska and Montana suggest that these animals were eating similar food items. There appears to be good correlation between tooth size and body size in theropods, thereby allowing the inference that the increase in the size of Alaskan Troodon teeth equates to an increase in body size. The increased body size for Alaskan Troodon is likely related to increased availability of food resources as a result of decreased numbers of other predatory dinosaurs, particularly tyrannosaurids, in the ecosystem.