The world's rarest whale, the spade-toothed beaked whale, has been sighted for the first time, according to scientists from the University of Auckland.
In December 2010, a 5.3m-long female whale and a 3.5m male calf stranded and later died on Opape Beach in the Bay of Plenty. After death they were measured, photographed and tissue samples were taken by the Department of Conservation.
They were initially misidentified as Gray's beaked whales - the most common beaked whale to strand in New Zealand - however, subsequent genetic analysis revealed they were spade-toothed beaked whales.
"It's incredible to think that, until recently, such a large animal was concealed in the South Pacific Ocean and shows how little we know about ocean biodiversity," said lead scientist Rochelle Constantine.
The spade-toothed beaked whale was discovered on Pitt Island in the Chatham Islands in 1872, but it wasn't until 2002 that scientists analysed DNA from the three skull fragments, recovered from museum archives, and realised that their genetic profiles were the same and did not correspond to any other known species.
Until the latest stranding, however, it was unclear whether the species still existed.
"This is a real New Zealand story - it's all linked here, from the discovery of two of the bone fragments to the identification of the species and now the first sighting of the whales," said Dr Constantine.