The Chatham duck or Chatham Island duck (Anas chathamica) is an extinct species of duck, formerly placed in a monotypic genus Pachyanas, which once lived in New Zealand’s Chatham Islands in the south-west Pacific Ocean. It was described by Walter Oliver (as a "stoutly built duck") from bird bones in the collection of the Canterbury Museum in 1955 in the second edition of his work New Zealand Birds. Recently, analysis of mitochondrial DNA extracted from subfossil remains showed that the Chatham duck was not, in fact, closely related to shelducks but instead belongs in the genus Anas: the dabbling ducks. Its closest living relatives appear to be the Auckland teal, Campbell teal and the brown teal from New Zealand. Some authors have suggested that the Chatham duck was flightless; however,