A new Paleogene procellariiform bird from western North America

A new procellariiform bird is described from the latest Eocene or early Oligocene Jansen Creek Member of the Makah Formation in northwestern Washington State, USA. Makahala mirae gen. et sp. nov. is only the second record of a procellariiform bird from Paleogene rocks of North America. The new species is characterized by a presumably plesiomorphic absence of a processus supracondylaris dorsalis of the humerus and an unusually enlarged distal end of the radius. The latter feature is an autapomorphy of M. mirae that distinguishes the species not only from other Procellariiformes, but from all other neornithine birds. The functional significance of this derived morphology of the distal radius is unknown, but is likely to have been correlated with characteristics of the wing shape or flight style of the new species.