 In 1856 , Joseph Leidy described two tyrannosaurid premaxillary teeth from Montana . Although there was no indication of what the animal looked like , the teeth were large and robust , and Leidy gave them the name Deinodon . Matthew and Brown commented in 1922 that these teeth were indistinguishable from those of Gorgosaurus , but in the absence of skeletal remains of Deinodon , opted not to unequivocally <unk> the two genera , provisionally naming a ? Deinodon libratus . Although Deinodon teeth are very similar to those of Gorgosaurus , tyrannosaurid teeth are extremely uniform , so it cannot be said for certain which animal they belonged to . Deinodon is usually regarded as a nomen dubium today . Additional likely synonyms of G. libratus and / or D. horridus include Laelaps <unk> , Laelaps <unk> , Laelaps incrassatus , and Dryptosaurus <unk> . 
