Avisauridae

The Avisauridae are a family of extinct Enantiornithine birds known from Cretaceous North and South America. . They are represented by four genera.

Avisauridae was erected by Brett-Surman and Paul in 1985. They included in this Family a few fossils that they believed belonged to small non — avian dinosaurs.

Chiappe (1992) later reassigned the Avisauridae to the Class Aves and the Subclass Enantiornithes. Chiappe (1993) diagnosed the Family as "Enantiornithine birds with a strong transverse convexity of the dorsal surface of the mid — shaft of metatarsal III, a distinct plantar projection of the medial rim of the trochlea of Metatarsal III, and a laterally compressed J-shaped metatarsal I." He defined the Family as the common ancestor of Neuquenornis volans and Avisaurus archibaldi plus all its descendants.

Chiappe and Calvo (1994) found that the Avisauridae shared adaptations of the foot — including a fully reversed and distally placed hallux with a large claw — that indicated the ability to perch in trees. They argued that an arboreal habit was most likely for all of the Avisauridae.