Claim: Some studies have found Ambiortus to be closely related to the Ichthyornithes, but most analyses have found it to be either an unresolved member of the Ornithurae,  meaning "bird tails" in Greek.
Evidence: Ambiortus is a prehistoric bird genus. Some studies have found it to be closely related to the Ichthyornithes, a relatively advanced group closely related to modern birds. However, most analyses have found it to be either an unresolved member of the Ornithurae, or a more primitive member of Ornithuromorpha. Ornithurae (meaning "bird tails" in Greek) is a natural group which includes the common ancestor of Ichthyornis, Hesperornis, and all modern birds as well as all other descendants of that common ancestor.