In 1993, the first "Hesperornis" remains from outside of North America were recognized as a new species by Nessov and Yarkov. They named "Hesperornis rossicus" for a fragmentary skeleton from the early Campanian of Russia near Volgograd. Several other specimens from contemporary deposits have since been referred to this species. At about long, "H. rossicus" was the largest species of "Hesperornis" and among the largest hesperornithines, slightly smaller than the large Canadian genus "Canadaga". Aside from its large size and different geographic location, "H. rossicus" differs from other "Hesperornis" in several features of the lower leg and foot, including a highly flattened metatarsus.