Toothed diving bird — Hesperornis regalis

Geologic period: Late Cretaceous

Age: Late Cretaceous, Niobrara Formation.

Feeding: Predatory aquatic feeding.

Locomotion: Specialized diving and swimming; poor or absent powered flight.

Body plan: Streamlined aquatic bird with powerful hind limbs, reduced wings and jaws containing teeth.

Evidence: Hind-limb anatomy and toothed jaws are direct evidence. Swimming performance is reconstructed from skeletal anatomy.

Why it matters: Hesperornis shows that birds had already diversified into highly specialized aquatic forms while many birds still retained teeth.

Plain Language Identity: A large flightless toothed diving bird of the Late Cretaceous.

What You Are Looking At: A composite reconstruction based on fossil remains of Hesperornis regalis.

Ecosystem: Western Interior Seaway.

Formation: Niobrara Formation.

Find Location: Kansas, United States.

Preservation: Composite display.

Open Questions: Do not treat toothed birds as evolutionary failures; they represent successful Cretaceous bird lineages.

Source Urls: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list; https://www.si.edu/object/hesperornis-regalis-marsh-1872:nmnhpaleobiology_3371014

Enrichment Method: SAGE curated research pass; title + scientific name + source scene matched; comparative chronology retained; evidence separated from inference

Scientific name: Hesperornis regalis

Evidence / representation: comparative_taxon_visual

comparative_taxon_visual

Cretaceous Worlds: Dinosaurs at Their Most Diverse.

Media license: CC BY-SA 2.0

https://creativecommons.org/licenses/by-sa/2.0