Trachodon

Trachodon
Temporal range: Late Cretaceous,
Illustration of the isolated teeth
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Ornithischia
Clade: Ornithopoda
Family: Hadrosauridae
Genus: Trachodon
Leidy, 1856
Species:
T. mirabilis
Binomial name
Trachodon mirabilis
Leidy, 1856
Synonyms

Trachodon (meaning "rough tooth") is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-aged (Upper Cretaceous) Judith River Formation of Montana, U.S. It is a historically important genus with a convoluted taxonomy that has been all but abandoned by modern dinosaur paleontologists. Despite being used for decades as the iconic hadrosaurid dinosaur, the material it is based on is composed of teeth from both hadrosaurids and ceratopsids (their teeth have a distinctive double root), and its describer, Joseph Leidy, came to recognize the difference and suggested limiting the genus to what would now be seen as ceratopsid teeth. Restricted to the hadrosaurid teeth, it may have been a lambeosaurine.