Harlequin Duck - Taxonomy

Taxonomy

Today, this is the only species of its genus. Two prehistoric harlequin ducks were described from fossils, although both were initially placed in a distinct genus: Histrionicus shotwelli is known from Middle to Late Miocene deposits of Oregon, USA and was considered to form a distinct monotypic genus, Ocyplonessa. Histrionicus ceruttii, which lived in California during the Late Pliocene, was at first taken to be a species of the related genus Melanitta. The species is traditionally considered monotypic. The Eastern and Western populations are sometimes recognized as two different subspecies, the Eastern race being the nominate H. histrionicus histrionicus, and the Western race as H. h. pacificus, but there has been doubt on the validity of this taxon.