The magpie goose (Anseranas semipalmata) is the sole living representative species of the family Anseranatidae. This common waterbird is found in northern Australia and southern New Guinea.[2] As the species is prone to wandering, especially when not breeding, it is sometimes recorded outside its core range.[2] The species was once also widespread in southern Australia, but disappeared from there largely due to the drainage of the wetlands where the birds once bred. Due to their importance to Aboriginal people as a seasonal food source,[3] as subjects of recreational hunting,[4] and as a tourist attraction, their expansive and stable presence in northern Australia has been "ensured protective management".[5]
Magpie geese are unmistakable birds with their black and white plumage and yellowish legs. The feet are only partially webbed, and the magpie goose feeds on vegetable matter in the water, as well as on land. Males are larger than females. Unlike true geese, their moult is gradual, so no flightless periods result. Their voice is a loud honking.
This species is placed in the order Anseriformes, having the characteristic bill structure, but is considered to be distinct from the other species in this taxon. The related and extant families, Anhimidae (screamers) and Anatidae (ducks, geese, and swans), contain all the other taxa. The magpie goose is contained in the genus Anseranas and family Anseranatidae, which are monotypic now.[6]
A cladistic study of the morphology of waterfowl found that the magpie goose was an early and distinctive offshoot, diverging after screamers and before all other ducks, geese, and swans.[7]
This family is quite old, a living fossil, having apparently diverged before the Cretaceous–Paleogene extinction event — the relative Vegavis iaai lived some 68-67 million years ago. The fossil record is limited, nonetheless. The enigmatic genus Anatalavis (Hornerstown Late Cretaceous or Early Paleocene of New Jersey, USA - London Clay Early Eocene of Walton-on-the-Naze, England) is sometimes considered to be the earliest known anseranatid. Other Paleogene birds sometimes considered magpie-geese are the genera Geranopsis from the Hordwell Formation Late Eocene to the Early Oligocene of England and Anserpica from the Late Oligocene of Billy-Créchy (France).[8]
The earliest known member of the group in Australia is Eoanseranas represented by fossils found in the late Oligocene Carl Creek Limestone of Queensland.[9] Additional fossils from North America and Europe suggest that the family was spread across the globe during the late Paleogene period.[10] The Australian distribution of the living species ties in well with the presumed Gondwanan origin of Anseriformes, but Northern Hemisphere fossils are puzzling. Perhaps the magpie geese were one of the dominant groups of Paleogene waterfowl, only to become largely extinct later.[original research?]