Duck bones dominate bird bones in the St Bathans Fauna. Among them are a few distinctive bones referred to the endemic monotypic genus Dunstanetta, named after the Dunstan Range that overlooks the fossil site. Dunstanetta is placed in the subfamily Oxyurinae (stiff-tailed ducks).

The St Bathans Fauna waterfowl species have mainly been defined based on the size and form of their humeri (upper wing bones). Johnstones’ duck was larger than the four other duck species, but smaller than the St Bathans shelduck.

Johnstones’ duck was described from seven bones, five of which (the paratype series) are thought to have been from the same individual. All the bones are from a 19-16 million-year-old (Early Miocene) lake-bed deposit on the true left bank of the Manuherikia River, St Bathans, central Otago. The holotype (NMNZ S.41007, a distal left humerus) and paratype series (NMNZ S.42481-5) are held at Museum of New Zealand Te Papa Tongarewa. The species is named after Ann & Euan Johnstone, the owners of Home Hills Station where the bones were found.

Johnstones’ duck was a highly specialised diving duck. There are no stiff-tailed ducks remaining in the New Zealand fauna, but three species in three genera (Malacorhynchus, Oxyura, Biziura) became extinct following human contact.

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References

Worthy, T.H.; Lee, M.S.Y. 2008. Affinities of Miocene waterfowl (Anatidae: Manukerikia, Dunstanetta and Miotadorna) from the St Bathans Fauna, New Zealand. Palaeontology 51: 677-708.

Worthy, T.H.; Tennyson, A.J.D.; Jones, C.; McNamara, J.A.; Douglas, B.J. 2007. Miocene waterfowl and other birds from central Otago, New Zealand. Journal of Systematic Palaeontology 5: 1-39.

Recommended citation

Miskelly, C.M. 2013. Johnstones’ duck. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz