A Giant Presbyornis (Aves, Anseriformes) and Other Birds from the Paleocene Aquia Formation of Maryland and Virginia

Abstract

Presbyornis isoni, new species, is described from a humerus and an alar phalanx from marine sediments of the late Paleocene Aquia Formation in Maryland. About the size of the smallest living species of crane (Gruidae), it was much larger than any previously known member of the Presbyornithidae. Other fragmentary bird remains from the Aquia Fromation are noted, several of which may be referable to the suborder Phaethontes of the Pelecaniformes. Additional Paleocene birds from eastern North America occur in the Hornerstown Formation of New Jersey, which is now considered to be Danian (early Paleocene) in age, rather than late Cretaceous.