CBC’s Quirks & Quarks has a segment about the first known bird beak.  It belongs to Ichthyornis a bird that dates to about 80 million years ago, during the Cretaceous Period.  The species was first identified in the 1870’s and named by Othniel Charles Marsh, of Yale’s Peabody Museum of Natural History.  The original paper appears in the journal Nature.

Recently, however, newly discovered fossils of Ichthyornis came into the hands of Canadian paleontologist Dr. Bhart-Anhan Bhullar, an assistant professor in the Departments of Geology and Geophysics at Yale University, and the Assistant Curator of Yale’s Peabody Museum of Natural History. The new fossils included one remarkably complete skull, with well preserved three-dimensional features.

The skulls indicate that Ichthyornis retained many features of its dinosaur ancestors. There are holes in the skull that would have supported large jaw-closing muscles, more like dinosaurs than modern birds. In modern birds, those muscles became smaller to make room for a bigger brain. Also Ichthyornis retained teeth used in its powerful dinosaur-like bite. But at the tip of the snout the animal had a small, but serviceable, beak.