Ichthyornis

Ichthyornis is an extinct genus of toothed seabirds that lived during the Late Cretaceous period. Fossils of Ichthyornis have been found in North America, primarily in chalk deposits of Kansas. These ancient birds were roughly the size of a modern gull or tern and possessed a striking combination of primitive and advanced features. Perhaps the most notable characteristic of Ichthyornis was its well-developed teeth, which were set in sockets rather than grooves. These teeth were likely used to grasp slippery prey, such as fish and crustaceans, which formed the basis of its diet. Despite having teeth, Ichthyornis also possessed a beak, though it was relatively short and stout. Its skeletal structure reveals adaptations for powerful flight, with a keeled sternum for the attachment of flight muscles and strong pectoral bones. The wings were proportionally long, suggesting it was a capable aerial predator. Ichthyornis also had a bird-like pelvis, distinguishing it from some of its more reptilian ancestors. The discovery of Ichthyornis was significant in understanding the evolutionary transition from dinosaurs to birds, demonstrating that toothed birds coexisted with early avian forms and even some feathered dinosaurs.