Ginkgo-toothed beaked whale

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Ginkgo-toothed beaked whale
Mesoplodon ginkgodens 2.jpg
Ginkgo-toothed beaked whale size.svg
Size compared to an average human
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Ziphiidae
Genus: Mesoplodon
Species:
M. ginkgodens
Binomial name
Mesoplodon ginkgodens
Nishiwaki and Kamiya, 1958
Cetacea range map Ginkgo-toothed Beaked Whale.png
Ginkgo-toothed beaked whale range

The ginkgo-toothed beaked whale (Mesoplodon ginkgodens) is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical-looking species, but is notable for the males not having any scarring. [3]

Contents

Description

A ginko-toothed beaked whale skull located at the Okinawa Churaumi Aquarium, Japan. Mesoplodon ginkgodens by OpenCage.jpg
A ginko-toothed beaked whale skull located at the Okinawa Churaumi Aquarium, Japan.

Ginkgo-toothed beaked whales are more robust than most mesoplodonts, but otherwise look fairly typical. Halfway through the jaw, there is a sharp curve up where the ginkgo leaf-shaped tooth is.

Unlike other species such as Blainville's beaked whale and Andrews' beaked whale, the teeth do not arch over the rostrum. The beak itself is of a moderate length.

The coloration is overall dark gray on males with light patches on the front half of the beak and around the head, and small white spots on the bottom of the tail, but the location may be variable. Females are a lighter gray and have countershading.

Both sexes reach 4.9 meters (16 feet) in length. They are around 2.4 meters (7.9 feet) long when born.

Population and distribution

This beaked whale has had fewer than 20 strandings off the coasts of Japan, Taiwan, [4] California, the Galapagos Islands, New South Wales, New Zealand, Sri Lanka, the Maldives, and the Strait of Malacca. [5] Its range is essentially tropical and temperate waters in the Indian and Pacific Ocean. There are currently no population estimates.

A potential sighting occurred in the South China Sea in May 2019, although it was possible the sighted whales were Deraniyagala's beaked whales. [6] [7] In February 2021, a pod of three whales was sighted at the Parengarenga Canyons, off North Cape (Otou), New Zealand. [8] [9]

Behavior

Unlike all other known members of Ziphiidae, there is no evidence that the males engage in combat, although this may be due to a limited sample size. The species probably feeds primarily on squid. [10] No other information is known.

Conservation

The only observations of this species while alive have come from hunters off the coasts of Japan and Taiwan, who occasionally take an individual. They are also affected by drift gillnets. One individual, identified from a DNA sample, was known to have interacted with a pelagic longline fishery in the central and western Pacific Ocean. The ginkgo-toothed beaked whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU). [11]

Specimens

See also

Related Research Articles

Beaked whales are a family of cetaceans noted as being one of the least-known groups of mammals because of their deep-sea habitat, reclusive behavior and apparent low abundance. Only three or four of the 24 existing species are reasonably well-known. Baird's beaked whales and Cuvier's beaked whales were subject to commercial exploitation, off the coast of Japan, while the northern bottlenose whale was extensively hunted in the northern part of the North Atlantic in the late 19th and early 20th centuries.

<span class="mw-page-title-main">Andrews' beaked whale</span> Species of mammal

Andrews' beaked whale, sometimes known as the deep-crest beaked whale or splay-toothed whale, is one of the least known members of a poorly known genus. The species has never been observed in the wild, and is known only from specimens washed up on beaches.

<i>Mesoplodon</i> Genus of beaked whales

Mesoplodont whales are 16 species of toothed whale in the genus Mesoplodon, making it the largest genus in the cetacean order. Two species were described as recently as 1991 and 2002, and marine biologists predict the discovery of more species in the future. A new species was described in 2021. They are the most poorly known group of large mammals. The generic name "mesoplodon" comes from the Greek meso- (middle) - hopla (arms) - odon (teeth), and may be translated as 'armed with a tooth in the centre of the jaw'.

<span class="mw-page-title-main">Sowerby's beaked whale</span> Species of mammal

Sowerby's beaked whale, also known as the North Atlantic or North Sea beaked whale, is a species of toothed whale. It was the first mesoplodont whale to be described. James Sowerby, an English naturalist and artist, first described the species in 1804 from a skull obtained from a male that had stranded in the Moray Firth, Scotland, in 1800. He named it bidens, which derives from the two teeth present in the jaw, now known to be a very common feature among the genus.

<span class="mw-page-title-main">Hubbs' beaked whale</span> Species of mammal

Hubbs' beaked whale was initially thought to be an Andrews' beaked whale when discovered by ichthyologist Carl Hubbs; however, it was named in his honor when it was discovered to be a new species. This species has the typical dentition found in the genus, but its main outstanding features are a white "cap" on the head and very extensive scarring. The species is known from 31 strandings, a few at-sea sightings, and observations of two stranded whales that were kept in captivity for 16–25 days.

<span class="mw-page-title-main">Blainville's beaked whale</span> Species of mammal

Blainville's beaked whale, or the dense-beaked whale, is believed to be the widest ranging mesoplodont whale. The French zoologist Henri de Blainville first described the species in 1817 from a small piece of jaw — the heaviest bone he had ever come across — which resulted in the name densirostris. Off the northeastern Bahamas, the animals are particularly well documented, and a photo identification project started sometime after 2002.

<span class="mw-page-title-main">Gervais's beaked whale</span> Species of whale

Gervais's beaked whale, sometimes known as the Antillean beaked whale, Gulf Stream beaked whale, or European beaked whale is the most frequently stranding type of mesoplodont whale off the coast of North America. It has also stranded off South America and Africa.

<span class="mw-page-title-main">Gray's beaked whale</span> Species of mammal

Gray's beaked whale, sometimes known as Haast's beaked whale, the scamperdown whale, or the southern beaked whale, is one of the better-known members of the genus Mesoplodon. This species is fairly gregarious and strands relatively frequently for a beaked whale. In the Māori language, this species is called hakurā or iheihe.

<span class="mw-page-title-main">Hector's beaked whale</span> Species of mammal

Hector's beaked whale, is a small mesoplodont living in the Southern Hemisphere. This whale is named after Sir James Hector, a founder of the colonial museum in Wellington, New Zealand. The species has rarely been seen in the wild.

<span class="mw-page-title-main">Strap-toothed whale</span> Species of whale

The strap-toothed beaked whale, also known as Layard's beaked whale, is one of the largest members of the mesoplodont genus, growing to 6.2 m (20 ft) in length and reaching up to 1,300 kg (2,900 lb). The common and scientific name was given in honor of Edgar Leopold Layard, the curator of the South African Museum, who prepared drawings of a skull and sent them to the British taxonomist John Edward Gray, who described the species in 1865.

<span class="mw-page-title-main">True's beaked whale</span> Species of mammal

True's beaked whale is a medium-sized whale in the genus Mesoplodon. It is native to the northern Atlantic Ocean. The common name is in reference to Frederick W. True, a curator at the United States National Museum.

<span class="mw-page-title-main">Tropical bottlenose whale</span> Species of mammal

The tropical bottlenose whale, also known as the Indo-Pacific beaked whale or Longman's beaked whale, was considered to be the world's rarest cetacean until recently, but the spade-toothed whale now holds that position. As of 2010, the species is now known from nearly a dozen strandings and over 65 sightings. This is the only species in the genus Indopacetus.

<span class="mw-page-title-main">Pygmy beaked whale</span> Species of mammal

The pygmy beaked whale, also known as the bandolero beaked whale, Peruvian beaked whale and lesser beaked whale, is the smallest of the mesoplodonts and one of the newest discoveries. There were at least two dozen sightings of an unknown beaked whale named Mesoplodon sp. A before the initial classification, and those are now believed to be synonymous with the species. The species was formally described in 1991, based on ten specimens obtained from Peru between 1976 and 1989, including a 3.72 m (12.2 ft) adult male as the type specimen. A specimen that stranded at Paracas, Peru in 1955 has since been identified as a pygmy beaked whale. Since 1987, there have been an additional 40 sightings of the species, for a total of 65.

<span class="mw-page-title-main">Stejneger's beaked whale</span> Species of mammal

Stejneger's beaked whale, also known as the Bering Sea beaked whale or the saber-toothed whale, is a relatively unknown member of the genus Mesoplodon inhabiting the North Pacific Ocean. Leonhard Hess Stejneger collected the type specimen on Bering Island in 1883, from which Frederick W. True provided the species' description in 1885. In 1904, the first complete skull was collected, which confirmed the species' validity. The most noteworthy characteristic of the males is the very large, saber-like teeth, hence the name.

<span class="mw-page-title-main">Arnoux's beaked whale</span> Species of whale

Arnoux's beaked whale, also called the southern four-toothed whale, southern beaked whale, New Zealand beaked whale, southern giant bottlenose whale and southern porpoise whale is one of the species of Berardius. Arnoux's and Baird's beaked whales are so similar that researchers have debated whether or not they are simply two populations of the same species, until genetic evidence and their wide geographical separation led them to be classified as separate. Little is known about their behavior due to infrequent encounters with live individuals.

<span class="mw-page-title-main">Perrin's beaked whale</span> Species of mammal

Perrin's beaked whale is part of the toothed whale suborder and is one of over 90 known cetaceans in existence today. Beaked whales are part of the family Ziphiidae, which are the second most diverse group out of all marine mammals with over 20 species currently recognized. Although diverse, little is understood about these timid, deep divers that can dive for up to two hours. The whales are partially named after their beak shaped jaw, which extends from their small head. The genus name Mesoplodon comes from the Greek meanings of meso- (middle), - hopla (arms), - odon (teeth), and may be translated as 'armed with a tooth in the center of the jaw'.

<span class="mw-page-title-main">Spade-toothed whale</span> Species of beaked whale

The spade-toothed whale is a very little-known species, the rarest species of beaked whale.

Deraniyagala's beaked whale is a species of mesoplodont whale closely related to the ginkgo-toothed beaked whale.

References

  1. Pitman, R.L.; Brownell Jr.; R.L. (2020). "Mesoplodon ginkgodens". IUCN Red List of Threatened Species . 2020: e.T127827012A127827154. doi: 10.2305/IUCN.UK.2020-3.RLTS.T127827012A127827154.en . Retrieved 19 November 2021.
  2. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. Nishiwaki, M.; Kasuya, T.; Kureha, K.; Oguro, N. (1972). "Further comments on Mesoplodon ginkgodens" (PDF). Scientific Reports of the Whales Research Institute. 24: 43–56. Retrieved 26 February 2019.
  4. 黃力勉, 2014, 5.1米柯維氏喙鯨 擱淺蘭嶼. 台東報導
  5. Dalebout, Merel Louise (2002). Species identity, genetic diversity, and molecular systematic relationships among the Ziphiidae (beaked whales). ProQuest: The University of Auckland (New Zealand). p. 249.
  6. Hansen, Cypress (14 January 2021). "Rare beaked whale sighting could be a world first for the species". Mongabay. Retrieved 29 January 2021.
  7. Rosso, Massimiliano; Lin, Mingli; Caruso, Francesco; Liu, Mingming; Dong, Lijun; Borroni, Anna; Lin, Wenzhi; Tang, Xiaoming; Bocconcelli, Alessandro; Li, Songhai (2 December 2020). "First live sighting of Deraniyagala's beaked whale (Mesoplodon hotaula) or ginkgo‐toothed beaked whale (Mesoplodon ginkgodens) in the western Pacific (South China Sea) with preliminary data on coloration, natural markings, and surfacing patterns". Integrative Zoology. 16 (4): 451–461. doi:10.1111/1749-4877.12507. PMID   33289310. S2CID   227947326.
  8. "Scientists photograph rare ginkgo-toothed beaked whale". RNZ. 2021-02-05. Retrieved 2021-02-05.
  9. "Rare whale spotted swimming for first time ever in New Zealand waters". NZ Herald. Retrieved 2021-02-05.
  10. MacLeod, Colin (January 1998). "Intraspecific scarring in odontocete cetaceans: an indicator of male 'quality' in aggressive social interactions?". Journal of Zoology. 244: 71–77. doi:10.1017/s0952836998001083 via Wiley Online Library.
  11. Official webpage of the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region