The world's rarest whale, previously only known from a few bones, was seen for the first time on a New Zealand beach, according to a new Current Biology paper.

The elusive marine mammal is the spade-toothed beaked whale (Mesoplodon traversii). The good news is that it was seen at all, revealing that it still exists. The bad news is that the sighting was of a mother and her male calf, both of which became stranded and died on the beach.

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"This is the first time this species — a whale over five meters (about 16.5 feet) in

length — has ever been seen as a complete specimen, and we were lucky

enough to find two of them," Rochelle Constantine of the University

of Auckland said in a press release. "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."

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The discovery actually happened two years ago, when the whales live-stranded and died on Opape Beach, New Zealand. It's only after DNA analysis that the identification of the rare species was made. At first, they were incorrectly identified as being the much more common Gray's beaked whales.

"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," Constantine said. "We ran

the samples a few times to make sure before we told everyone."

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Constantine suspects that the whales "are simply an offshore species that lives and

dies in the deep ocean waters and only rarely wash ashore. New Zealand is surrounded by massive oceans. There is a lot of

marine life that remains unknown to us."

(Image: New Zealand Government)