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'.
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.
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.
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.
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.
The ginkgo-toothed beaked whale 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.
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.
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.
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.
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.
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.
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.
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.
The hourglass dolphin is a small dolphin in the family Delphinidae that inhabits offshore Antarctic and sub-Antarctic waters. It is commonly seen from ships crossing the Drake Passage, but has a circumpolar distribution.
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'.
The spade-toothed whale is a very little-known species, the rarest species of beaked whale.
The southern bottlenose whale is a species of whale, in the Ziphiid family, one of two members of the genus Hyperoodon. Seldom observed, the southern bottlenose whale is resident in Antarctic waters. The species was first described by English zoologist William Henry Flower in 1882, based on a water-worn skull from Lewis Island, in the Dampier Archipelago, Western Australia. They live in deep ocean waters over 1000 meters.
