Apatodon is a dubious genus of dinosaur, possibly synonymous with Allosaurus. When Marsh named it, he thought it was a jaw with a tooth from a Mesozoic pig, but it was soon shown that the specimen was an eroded vertebra, from a dinosaur possibly from the Morrison Formation of the Rocky Mountain region (the provenance data was unclear). Marsh had misidentified the neural spine as the tooth of a pig-like animal (Baur, 1890). The only recovered specimen is not regarded as sufficient to identify a particular species of dinosaur. However, it is now considered by some authors (George Olshevsky in particular) likely to have been from Allosaurus fragilis. The issue is now beyond resolution; however, as the type bone fragment has been lost. The name was derived from Greek: απατη ("trick", "deceit") and οδους (genitive οδοντος) ("tooth", in reference to its original, incorrect identification).