Odontognathae

The group was originally proposed by Alexander Wetmore, who attempted to link fossil birds with the presence of teeth, specifically of the orders Hesperornithiformes and Ichthyornithiformes.

As such they would be regarded as transitional fossils between the reptile-like "Archaeornithes" like Archaeopteryx and modern birds.

[1] Unlike the dinosaur-like "Archaeornithes", the various types of birds assigned to the Odontognathae had short tails with a plowshare-shaped pygostyle and a well developed carina for flight muscle.

They also shared the feature of intramandibular articulation, something that is actually absent in Archaeopteryx, but found in many of its theropod relatives.

[3] Ornithologist Alan Feduccia has used this, and the presence of the intramandibular articulation (a trait also found in mosasaurs and living varanid lizards) as arguments that the Odontognathae and thus the birds as a whole have not evolved from theropod dinosaurs, but non-dinosaur thecodonts.