The spade-toothed whale (Mesoplodon traversii) is a little-known species of beaked whales. They were first discovered in 1872 when bone fragments were found on Pitt Island, in New Zealand.
The scientists published their findings in the journal Current Biology. In the last 140 years, the only signs of the existence of these whales were in two partial skulls. M. traversii is considered to be the least known and rarest species of whale. A mother and her male calf beached and died on a New Zealand beach in December 2010. It was only after the researchers ran their DNA that they realized that these were M. traversii.
M. traversii is part of a family of whales that can dive more than 800m, and stay under for up to 87 minutes. There are currently 21 species of beaked whales, but there isn’t much information about them.
No intact specimens had been discovered before this. Initially, the two M. traversii specimens were mistaken for the more common Gray’s beaked whales (Mesoplodon grayi).
Besides the basic skull morphology, not much was known until now. The whales were stranded and died on Opape Beach in New Zealand. The female was 5.3 meters in length and the young calf was 3.5 m long.
M. traversii differs from other beaked whales by the coloration of the rostrum, which is either dark gray or black, compared to the white of M. grayi. M. traversii also has a dark eye patch, white belly, and dark flippers.
There is still no indication of how many of these whales exist in the wild, but the researchers conclude, “We can now confirm that the spade-toothed whale is extant and for the first time we have a description of the world’s rarest and perhaps most enigmatic marine mammal.”
Reference: “The world’s rarest whale” by Kirsten Thompson, C. Scott Baker, Anton van Helden, Selina Patel, Craig Millar and Rochelle Constantine, 6 November 2012, Current Biology.