Ichthyornis was a genus of toothed seabirds from the Late Cretaceous of North America. Itsfossil remains are known from the chalks of Alberta, Alabama, Kansas, New Mexico, Saskatchewan, and Texas, in strata that were laid down in the Western Interior Seaway during the Turonian-Campanian ages, about 95-85 mya. Ichthyornis is a common component of the Niobrara Formation fauna, and numerous specimens of both adult and immature individuals have been found. Ichthyornis has been historically important in shedding light on bird evolution. It was the first discovered prehistoric bird preserved with teeth, andCharles Darwin noted its significance during the early years of the theory of evolution. Ichthyornis remains important today as it is one of the few Mesozoic era birds known from more than a few specimens.