Quirks & Quarks

A new fossil reveals the first bird beak - and it came with teeth as well

A study of the skull of Ichthyornis suggests the first known beaked bird still had a lot of dinosaur features, including teeth
The toothed early bird Ichthyornis showing the first form of the avian beak (Michael Hanson and Bhart-Anjan Bhullar)
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Did this early bird have a beak? 

Ichthyornis was an ancient bird that lived in what is now the mid-west of North America between 100 and 66 million years ago. It was a seabird  about the size of a tern or gull, with a 60 centimetre wing span. It was first identified in the 1870's, but the early specimens were missing key features.  The skeleton of the body was well preserved, but the heads were in poor condition. It was clear that Ichthyornis was quite similar to modern birds, but paleontologists were still very curious about the details of the head, which in modern birds is very different from their dinosaur ancestors.

The story the skull tells

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.

The beak

The beak of Ichthyornis would have been a primitive form of avian beak with tweezer-like tips on the end of long, toothy jaws. The beak would have been useful only for precision grabbing, manipulation and feather preening, but not for holding and cutting food the way the long beak of modern birds is used. Dr. Bhullar suggests that the beak first arose to act like a surrogate hand - since evolution was turning the dinosaur hands into wings. Given that the skull of Ichthyornis was a true mosaic of dinosaur and modern bird, scientists conclude that the transition from dinosaurs to modern birds was more complex than previously thought.