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| [A] Berardius minimus
Yamada, Kitamura, Abe, Tajima, Matsuda, Mead & Matsuishi, 2019
[B] B. bairdii (Stejneger, 1883)
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Abstract
Two types of Berardius are recognised by local whalers in Hokkaido, Japan. The first is the ordinary Baird’s beaked whale, B. bairdii, whereas the other is much smaller and entirely black. Previous molecular phylogenetic analyses revealed that the black type is one recognisable taxonomic unit within the Berardius clade but is distinct from the two known Berardius species. To determine the characteristics of the black type, we summarised external morphology and skull osteometric data obtained from four individuals, which included three individuals from Hokkaido and one additional individual from the United States National Museum of Natural History collection. The whales differed from all of their congeners by having the following unique characters: a substantially smaller body size of physically mature individuals, proportionately shorter beak, and darker body colour. Thus, we conclude that the whales are a third Berardius species.
Infraorder CETACEA Brisson, 1762
Parvorder ODONTOCETI Flower, 1864
Family ZIPHIIDAE Gray, 1865
Genus BERARDIUS Duvernoy, 1851
Berardius minimus sp. nov.
Etymology: The specific name reflects the smallest body size of physically mature individuals of this species compared with the other Berardius species. Historically, whalers in Hokkaido recognised this species as different from B. bairdii and called them “kuro-tsuchi”, which means black Baird’s beaked whale; however, the colour difference mainly depends on the scar density and is not biologically fundamental (Figs 1 and 2). We therefore chose the most basic difference, the significantly small body size, which is smallest among the congeners, to be reflected in the scientific name.
Diagnosis: Berardius minimus differs from all of its congeners by having the following unique characters: remarkably smaller body size of physically mature individuals, proportionately shorter beak, darker body colour subsequent noticeable cookie-cutter shark bites.
Tadasu K. Yamada, Shino Kitamura, Syuiti Abe, Yuko Tajima, Ayaka Matsuda, James G. Mead and Takashi F. Matsuishi. 2019. Description of A New Species of Beaked Whale (Berardius) found in the North Pacific. Scientific Reports. 9: 12723. nature.com/articles/s41598-019-46703-w
Two types of Berardius are recognised by local whalers in Hokkaido, Japan. The first is the ordinary Baird’s beaked whale, B. bairdii, whereas the other is much smaller and entirely black. Previous molecular phylogenetic analyses revealed that the black type is one recognisable taxonomic unit within the Berardius clade but is distinct from the two known Berardius species. To determine the characteristics of the black type, we summarised external morphology and skull osteometric data obtained from four individuals, which included three individuals from Hokkaido and one additional individual from the United States National Museum of Natural History collection. The whales differed from all of their congeners by having the following unique characters: a substantially smaller body size of physically mature individuals, proportionately shorter beak, and darker body colour. Thus, we conclude that the whales are a third Berardius species.
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| Figure 5: Illustrations of (A) Berardius minimus, and (B) B. bairdii. The black bars show 1 m. In general appearance, B. minimus resembles a small B. bairdii with a proportionately shorter beak and more spindle-shaped body (drawn by Yoshimi Watanabe, National Museum of Nature and Science). |
Systematics
Order CETARTIODACTYLA Montgelard, Catzeflis and Douzery, 1997.Infraorder CETACEA Brisson, 1762
Parvorder ODONTOCETI Flower, 1864
Family ZIPHIIDAE Gray, 1865
Genus BERARDIUS Duvernoy, 1851
Berardius minimus sp. nov.
(New Japanese name: Kurotsuchi-kujira)
Etymology: The specific name reflects the smallest body size of physically mature individuals of this species compared with the other Berardius species. Historically, whalers in Hokkaido recognised this species as different from B. bairdii and called them “kuro-tsuchi”, which means black Baird’s beaked whale; however, the colour difference mainly depends on the scar density and is not biologically fundamental (Figs 1 and 2). We therefore chose the most basic difference, the significantly small body size, which is smallest among the congeners, to be reflected in the scientific name.
Diagnosis: Berardius minimus differs from all of its congeners by having the following unique characters: remarkably smaller body size of physically mature individuals, proportionately shorter beak, darker body colour subsequent noticeable cookie-cutter shark bites.
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| Figure 2: Unidentified beaked whales sighted in Nemuro strait. Note the short beak, dark body colour, and sparse linear scars (photo taken by Hal Sato on 21 May 2009). |
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| Figure 4: Fresh carcass of Berardius minimus (male, 662 cm) found stranded on 10 November 2012 in Sarufutsu Hokkaido. (A) Ventral view of the carcass. Note the whole body is almost black except for the faintly white beak. (B) The relatively short beak of the same individual (photos taken by Yasushi Shimizu). |
Tadasu K. Yamada, Shino Kitamura, Syuiti Abe, Yuko Tajima, Ayaka Matsuda, James G. Mead and Takashi F. Matsuishi. 2019. Description of A New Species of Beaked Whale (Berardius) found in the North Pacific. Scientific Reports. 9: 12723. nature.com/articles/s41598-019-46703-w
