Michael Hanson And Bhart-Anjan S. Bhullar
Reconstructed Ichthyornis dispar skull (top) and artistic reproduction of its probable appearance (above)Michael Hanson And Bhart-Anjan S. BhullarA bird that lived between 95 million and 84 million years ago in what is now North America is helping scientists learn how the beak evolved. By analyzing four fossilized skulls—one discovered in 2014 and three older specimens from museums—researchers in the United States and the United Kingdom were able to accurately reconstruct the head of the Ichthyornis dispar. Described in 1873 by American paleontologist Othniel Marsh, this primitive bird was about the size of a pigeon and probably resembled the modern seagull. It is the oldest known bird species, and it had small teeth—about 1 millimeter in size and only visible when the beak was open—on both its upper and lower jaw. Reconstruction of the I. dispar skull suggests that a small structure composed entirely of keratin, the protein found in nails and horns, was initially formed at the end of the upper jaw bone known as the maxilla (Nature, May 3). “The first beak was a horn-covered pincer tip at the end of the jaw,” said paleontologist Bhart-Anjan Bhullar, a researcher at Yale University and coordinator of the study, in a press release. In modern birds, the horny beak completely covers the jaw and other bones of the mouth. According to the researchers, I. dispar was a transitional species classified somewhere between dinosaurs and modern birds. It had a relatively large brain and its jaw muscles were similar to those of other dinosaurs from which birds did not evolve.
Republish