Birds share a common ancestor - Archaeopteryx, which appeared in the Jurassic. Between it and modern birds were various intermediate forms, such as the Hesperornis of the Cretaceous.

The genus Hesperornis has three species - H. regalis, H. crassipes, and H. gracilis, distinguished by size. The largest is H. regalis, which was about 2 metres long, and resembled a modern diving bird. The short legs were located far back on the body, which would be unsuitable for terrestrial locomotion but advantageous for swimming. The wings were vestigial and the sternum without a keel. Like Archaeopteryx, and unlike modern birds, it had teeth. These served to grasp slippery fish, as do serrations on the beak of the American merganser. A joint between the lower jaw bones, similar to that of dinosaurs, allowed the bird to disengage the lower teeth from the prey and swallow it.

Othniel Charles Marsh (see the photo) discovered the first specimen in the Smoky Hill Chalk region of Kansas in 1871. The specimens found there are about 80 million years old (Late Cretaceous).


Location Map

Hesperornis illustration copyright Dan Varner.