The Bannockburn Swan was described from a few bones, recovered from 19–16 million-year-old (Early Miocene) lake-bed deposits on Dunstanburn and Home Hills stations, near St Bathans, central Otago, New Zealand. The type locality is beside Mata Creek.

The holotype (CM 2017.37.919, distal right humerus) is held at Canterbury Museum, Christchurch. Three other bones, all partial coracoids, are referred to this species and are held in the Museum of New Zealand Te Papa Tongarewa. The genus name Notochen refers to the southern origin of the fossil and the goose like swans of Australasia that are an endemic southern group. The species name bannockburnensis relates to the origin of the fossils from the Bannockburn Formation.

The Bannockburn Swan represents the fifth genus of waterfowl and the first member of the anserines (geese and swans) to be described from the St Bathans Fauna. It is the largest waterfowl species from this fauna, being a bird about the size of the Black Swan Cygnus atratus, although with a stouter humerus suggesting a more massive bird. No similar-sized anserines are known from Australia of this age, although the fossil record of waterfowl there is more depauperate than that of New Zealand, which might explain such an absence.

This species is relatively rare in the St Bathans Fauna, which likely relates to the size of its bones: bones of any bird of this size are very rare. The bones of the only other anserine known from the fauna, an unnamed species of anserine with similarities to Cereopsis novaehollandiae (the Cape Barren Goose), are equally rare. Nevertheless, bones attributed to the shelduck-like genus Miotadorna are many times more abundant, and it was a reasonably large bird, so perhaps these anserines were relatively rare on the palaeolake Manuherikia.

References

Worthy, T.H.; Scofield, R.P.; Hand, S.J.; De Pietri, V.L.; Archer, M. 2022. A swan-sized fossil anatid (Aves: Anatidae) from the early Miocene St Bathans Fauna of New Zealand. Zootaxa 5168 (1): 39–50.

Recommended citation

Worthy, T.H. 2024. Notochen bannockburnensis. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz