New finds of hesperornithids in the European Russia, with comments on the systematics of Eurasian Hesperornithidae

New remains of Hesperornithidae are described from several Late Cretaceous (Campanian) localities of the Lower Volga Region (European Russia). New specimens from Rychkovo and Karaykino localities cannot be referred to as Hesperornis rossicus Nessov et Yarkov, 1993 and likely represent a new undescribed species. Bones from Rychkovo belonged to immature individuals with an incompletely formed tarsometatarsus, which is comparable in size to those...