Beaked Whales, Ziphiidae, are the second largest group of Toothed Whales in terms of number of species, with 22 species in six genera. Despite this speciousness the group is not well studied, due to their preference for deep water environments and long dive times, which makes them rather hard to study. The genus Berardius currently contains two species, Baird’s Beaked Whale, Berardius bairdii, found in the North Pacific, and Arnoux’s Beaked Whale Berardius arnuxii, found in the Southern Ocean. However, Whalers from Hokkaido, the northernmost of Japan's four main islands, have long recognised two forms of Beaked Whale in the North Pacific, a larger grey form that corresponds to the official description of Baird’s Beaked Whale, and a smaller black form, which might potentially represent a different species.
In a paper published in the journal Scientific Reports on 30 August 2019, Tadasu Yamada of the Department of Zoology at the National Museum of Nature and Science, Shino Kitamura of the Sanriku Fisheries Research Centre, and the Faculty of Fisheries Sciences at Hokkaido University, Syuiti Abe, also of the Faculty of Fisheries Sciences at Hokkaido University, Yuko Tajima, also of the Department of Zoology at the National Museum of Nature and Science, Ayaka Matsuda, again of the Faculty of Fisheries Sciences at Hokkaido University, James Mead of the Division of Mammals at the Smithsonian Institution, and Takashi Matsuishi, once again of the Department of Zoology at the National Museum of Nature and Science, and of the Global Institution for Collaborative Research and Education at Hokkaido University, formally describe the smaller North Pacific Beaked Whalea as a new species of Berardius.
The new species is named Berardius minimus in reference to its smaller size, and is described on the basis of six specimens found dead either washed up on beaches or floating close to shore around the island of Hokkaido. The species is notably smaller than both other species of Berardius, with the largest specimen observed being only 6.9 m in length, as well as having a shorter, straighter and narrower beak, being darker in colour, almost black, with prominent white spots, and more prone to bites from Cookie-cutter Sharks. The species was found to be genetically distinct from Berardius bairdii, and to have somewhat different skeletal proportions.
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The new species is named Berardius minimus in reference to its smaller size, and is described on the basis of six specimens found dead either washed up on beaches or floating close to shore around the island of Hokkaido. The species is notably smaller than both other species of Berardius, with the largest specimen observed being only 6.9 m in length, as well as having a shorter, straighter and narrower beak, being darker in colour, almost black, with prominent white spots, and more prone to bites from Cookie-cutter Sharks. The species was found to be genetically distinct from Berardius bairdii, and to have somewhat different skeletal proportions.
Illustrations of (A) Berardius minimus, and (B) Berardius bairdii. The black bars show 1 m. In general appearance, Berardius minimus resembles a small Berardius bairdii with a proportionately shorter beak and more spindle-shaped body, Yoshimi Watanabe in Yamada et al. (2019).
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