The Indian spot-billed duck (Anas poecilorhyncha) is a species of large dabbling duck that is a non-migratory breeding duck throughout freshwater wetlands in the Indian subcontinent. The name is derived from the red spot at the base of the bill that is found in the mainland Indian population. When in water it can be recognized from a long distance by the white tertials that form a stripe on the side, and in flight it is distinguished by the green speculum with a broad white band at the base. This species and the eastern spot-billed duck (A. zonorhyncha) were formerly considered conspecific, together called the spot-billed duck (A. poecilorhyncha). The Indian spot-billed duck was described by the naturalist Johann Reinhold Forster in 1781 under its current binomial name Anas poecilorhyncha. The name of the genus Anas is the Latin word for a duck. The specific epithet poecilorhyncha combines the classical Greek words poikilos meaning "pied" or "spotted" and rhunkhos meaning a "bill". A molecular phylogenetic study published in 2009 that compared mitochondrial DNA sequences from ducks, geese and swans in the family Anatidae found that the Indian spot-billed duck was a sister species to a clade containing the Mexican duck, the American black duck, the mottled duck and the mallard. A 2014 study, however, shows that there is discordance between the phylogenies obtained using nuclear DNA sequences; the Indian spot-bill appears to be closer to the Laysan and Hawaiian ducks and forming a sister clade to the New World and Old World mallards and the Mexican, American black and mottled ducks. There is significant hybridization between Old World mallards and eastern spot-billed ducks, leading to a closeness in their mitochondrial DNA that alters the apparent phylogenies. Two subspecies are recognised although intergradation is possible (intermediates between haringtoni and eastern spot-billed duck have been recorded): A. p. poecilorhyncha Forster, 1781 – India and Sri Lanka A. p.