Erismatura Bonaparte, Giorn. Acad. Bo ma, liii, p. 208 (1832).
Type, Oxyura jamaicencens Gmelin.
The name Erismatura has recently been rejected by systematists for Bonaparte's earlier name Oxyura. This, however, cannot be used as it is preoccupied by Oxyurus of Rafinesque, 1814. This Bonaparte himself realized and therefore proposed the new name Erismatura.
In this genus the bill is large and very swollen at the base, the nail is small and curved inwards; the culmen is concave, the anterior part of the bill flat and broad and the lamellae coarse and set far apart; the nostrils are large, oval and placed nearer to the base than to the tip of the bill; the tarsi are short and placed far back as in the diving ducks; the feet are large and the hind toe is broadly lobed; the wings are short and pointed. Sexes slightly different.