Alexornis

Alexornis is a genus of enantiornithine birds from the La Bocana Roja Formation of Baja California, Mexico. This geological formation has been dated to the late Cretaceous period, and more specifically to the Cenomanian and Turonian ages, about 93.6 mya. The type and only known species is Alexornis antecedens. The scientific name as a whole means "Alex's ancestral bird"; Alexornis from the given name of ornithologist Alexander Wetmore + Ancient Greek ornis, "bird", and antecedens, Latin for "going before" or "ancestral".

A. antecedens is known only from a single fragmentary skeleton including shoulder, wing, and leg bones, but lacking a skull. It was about the size of a sparrow, weighing only about 35.6 grams (1.26 oz). The specimen was discovered in 1971 and formally described in 1976 by Pierce Brodkorb. Brodkorb considered the species to be similar to some modern birds, and at the time, recognized it as one of the few known Cretaceous "land birds" after Gobipteryx minuta, as most other Cretaceous birds at the time were thought to be aquatic or semi-aquatic.