Abstract:
Alexornis antecedens, new genus and species, is
described from the Bocana Roja Formation, Upper
Cretaceous (Campanian age), near El Rosario,
Baja California, Mexico. The humerus, ulna, scapula, coracoid, femur, and tibiotarsus are represented. The fossil is referred to a new family, Alexornithidae, and a new order, Alexornithiformes,
thought to be ancestral to the Tertiary and Recent
orders Coraciiformes and Piciformes. Since Caenagnathus collinsi Sternberg and C. sternbergi Cracraft are reptiles, and Gobipteryx minuta Elzanowski appears to be reptilian also, Alexornis is the
only certain land bird known from the Cretaceous.