Paronychodon

Paronychodon is known only from its teeth, which are about 1 to 2 centimeters long. No other bones have been found, so scientists call it a 'tooth taxon'.12

The teeth of Paronychodon have a D-shaped cross-section, with one flat side and one convex side. They also have low ridges running up the crown.1

When Edward Drinker Cope first named Paronychodon in 1876, he thought the tooth came from a plesiosaur, a marine reptile. He changed his mind later that year and said it was a carnivorous dinosaur.1

Paronychodon teeth have been found in rocks that are between 75 and 66 million years old, from the Campanian to the Maastrichtian stages of the Late Cretaceous.14

Some scientists think Paronychodon might be a troodontid, a group of small, bird-like dinosaurs. Others think it could be a dromaeosaurid, like Velociraptor.1

A second species, Paronychodon caperatus, was originally thought to be a mammal tooth and named Tripriodon by Othniel Charles Marsh in 1889.1