All ducks in the genus have, as their name implies, long, stiff tail feathers which are erect when the bird is resting.

[citation needed] The genus Oxyura was introduced (as a subgenus) in 1828 by the French naturalist Charles Lucien Bonaparte to accommodate a single taxon, Anas rubidus Wilson, 1814.

A fossil species from the Late Pliocene or Early Pleistocene of Jalisco (Mexico) was described as Oxyura zapatanima.

A larger Middle Pleistocene fossil form from the southwestern United States was described as Oxyura bessomi; it was probably quite close to the ruddy duck.

"Oxyura" doksana from the Early Miocene of Dolnice (Czech Republic) cannot be assigned to any anatine subfamily with certainty.