Greater scaup refers to a seabird mentioned by Aristotle and others and is thought to refer to a duck, auklet or other seabird. The species name "marila" is from the Greek word for charcoal embers or coal dust. The greater scaup was first studied by Linnaeus in 1761. Male greater scaup from America are distinguishable from those in Europe and Asia by the stronger vermiculations, worm-like carvings or marks on the mantle and scapulars, and are considered a separate subspecies, "A. m. nearctica". Females of the two subspecies are indistinguishable. Based on size differences, a Pleistocene paleosubspecies, "Aythya marila asphaltica", has also
Lesser scaup bill may give a hint; in the lesser scaup it has a stronger curve on the upperside than in the greater, resulting in a distal part that looks somewhat flattened and wide in the lesser scaup—hence the vernacular name "broadbill". If the birds fly, the most tell-tale sign is the white secondary remiges, whereas in the greater scaup the white extends on the primary remiges also, i.e. far towards the wingtip. Lesser scaup females show the characteristic darker iris (bright yellow in greater scaup males and females) at closer distances. Lesser scaup drakes in nuptial plumage are often said to