Hesperornis gracilis
Late Cretaceous: 85 million years ago – replica cast from fossils found in the Nebraska Formation in Logan County, Kansas.

From the interpretive panel at the Orlando Science Center:

“The skeletal features of the Hesperornis show that this bird was perfectly suited for aquatic life. Their small and stubby wings were presumably non-functional and their legs were set very far back on their body making life on land extremely difficult. But just like the modern penguins, in the water Hesperornis was a powerful swimmer and diver thanks to its short femur and long tibia.”