A team of biologists has made the first complete description of the spade-toothed beaked whale, Mesoplodon traversii, a whale species previously known only from a few skulls, after two individuals were found on a New Zealand beach.
“This is the first time this species – a whale over five meters in length – has ever been seen as a complete specimen, and we were lucky enough to find two of them,” said Dr Rochelle Constantine of the University of Auckland, senior author of a paper describing M. traversii in the journal Current Biology.
“Up until now, all we have known about the spade-toothed beaked whale was from three partial skulls collected from New Zealand and Chile over a 140-year period. It is remarkable that we know almost nothing about such a large mammal,” she said.
The two whales (a mother and her male calf) were discovered in December 2010, when they live-stranded and subsequently died on Opape Beach, New Zealand. The whales were initially identified not as spade-toothed beaked whales but as much more common Gray’s beaked whales. Their true identity came to light only following DNA analysis, which is done routinely as part of a 20-year program to collect data on the 13 species of beaked whales found in New Zealand waters.
“When these specimens came to our lab, we extracted the DNA as we usually do for samples like these, and we were very surprised to find that they were spade-toothed beaked whales,” Dr Constantine said. “We ran the samples a few times to make sure before we told everyone.”
“It may be that they are simply an offshore species that lives and dies in the deep ocean waters and only rarely wash ashore,” she said. “New Zealand is surrounded by massive oceans. There is a lot of marine life that remains unknown to us.”
Bibliographic information: Kirsten Thompson et al. 2012. The world’s rarest whale. Current Biology, vol. 22, no. 21, R905-R906; doi: 10.1016/j.cub.2012.08.055