| Khoikhoicetus Temporal range: probably Miocene | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Family: | Ziphiidae |
| Genus: | † Khoikhoicetus Bianucci, Lambert, and Post, 2007 |
| Species | |
| |
Khoikhoicetus is an extinct genus of ziphiid cetacean known from skulls found on seafloor sediments of probable Miocene age off the coast of South Africa and the Kerguelen Islands.
Two species are known, K. agulhasis and K. kergueleni. The genus Khoikhoicetus is closely related to beaked whales of the genera Mesoplodon , Hyperoodon , and Indopacetus . The two species differ from each other in their size and the width of the premaxillary crests. [1] [2]
Beaked whales are a group of cetaceans noted as being one of the least known groups of mammals because of their deep-sea habitat and apparent low abundance. Only three or four of the 22 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 late in the 19th and early 20th centuries.
Physeteroidea is a superfamily that, today, includes three extant species of whales: the sperm whale, in the genus Physeter, and the pygmy sperm whale and dwarf sperm whale, in the genus Kogia. In the past, these genera have sometimes been united in a single family, the Physeteridae, with the two Kogia species in the subfamily Kogiinae; however, recent practice is to allocate the genus Kogia to its own family, the Kogiidae, leaving the Physeteridae as a monotypic family, although additional fossil representatives of both families are known.
Mesoplodont whales are 15 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. 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'.
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.
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.
Four-toothed whales or giant beaked whales are beaked whales in the genus Berardius. They include Arnoux's beaked whale in cold Southern Hemisphere waters, and Baird's beaked whale in the cold temperate waters of the North Pacific. A third species, Berardius minimus, was distinguished from B. bairdii in the 2010s.
Zygophyseter varolai is an extinct sperm whale that lived during the Tortonian age of the Late Miocene 11.2 to 7.6 million years ago. It is known from a single specimen from the Pietra Leccese Formation in Italy. It was a member of a stem group of fossil macroraptorial sperm whales also including Brygmophyseter, Acrophyseter, and Livyatan. It probably grew to be around 6.5 to 7 meters in length and shared some characteristics with other raptorials, such as large teeth with tooth enamel that were functional in both the upper and lower jaws which the modern sperm whale lacks. It also had a beak, the ability to echolocate prey, and could have probably swum faster than the modern-day sperm whale which goes 4 kilometers per hour (2.5 mph). These were probably used in the capture of large prey, such as large fish, seals, and whales. In fact, its common name, the killer sperm whale, refers to its feeding habits that would have had a resemblance to the modern-day killer whale.
Brygmophyseter, known as the biting sperm whale, is an extinct genus of toothed whale in the sperm whale family with one species, B. shigensis. When it was first described in 1994, the species was placed in the genus Scaldicetus based on tooth morphology, but this was later revised in 1995. In 2006, it was classified into the genus Naganocetus, which is considered to be a junior synonym. The only known specimen, a nearly complete skeleton, was dated to be around 14–15 million years old. Brygmophyseter is thought to have been 7 meters (23 ft) long, and it probably had 11 or 12 teeth in the upper and lower jaws. Brygmophyseter is part of a group of macroraptorial sperm whales which tended to be apex predators using their large teeth to catch struggling prey such as whales. It had a spermaceti organ which was probably used for biosonar like in the modern sperm whale. The whale has made an appearance on The History Channel's TV series Jurassic Fight Club.
Australodelphis mirus is an extinct Pliocene dolphin. A. mirus is known from fossils found in the Sørsdal Formation, Mule Peninsula, Vestfold Hills, East Antarctica. The genus has been described as an example of convergent evolution with beaked whales.
Hyperoodon is a genus of beaked whale, containing just two species: the Northern and Southern bottlenose whales. While not in the genus Hyperoodon, Longman's beaked whales are alternatively called tropical bottlenose whales due to their physical features resembling those of bottlenose whales.
Choneziphius is an extinct genus of ziphiidae cetaceans, with two species known from the Miocene: C. planirostris and C. leidyi.
Globicetus is an extinct genus of ziphiidae cetaceans, with one species, G. hiberus, from the Miocene of Portugal and Spain. The holotype is a skull in the Museu da Lourinhã, in Portugal. G. hibrtus is notable for having a large, spherical mass of bone on its rostrum.
Imocetus is an extinct genus of ziphiidae cetaceans, with one species, G. piscatus, from the Miocene of Portugal and Spain. The etymology is after imum that means "ocean floor", and cetus that means "whale". Piscatus means "fished".
Tusciziphius is an extinct genus of ziphiid cetaceans. The distribution includes the Miocene of Portugal and Spain, and the Pliocene of Italy and the United States. Two species are known: T. atlanticus and T. crispus. The type specimen of T. crispus is IGF 1534, 1536, 1537, 1569, 1570, 1572, 1594 V, a partial skeleton. Its type locality is Case il Poggio, which is in a Zanclean coastal sandstone/claystone in Italy.
Squaloziphius is an extinct genus of odontocete cetacean from the Early Miocene (Aquitanian) aged marine deposits in Washington state.
Beneziphius is an extinct genus of ziphiid cetacean known from late Miocene to Pliocene marine deposits in Belgium and fishing grounds off Spain. The genus name honors Pierre-Joseph van Beneden, who pioneered the study of Neogene marine mammals from Belgium.
Africanacetus is an extinct genus of ziphiid cetacean known from skulls found in seafloor sediments of Late Miocene to Early Pliocene age off the coasts of South Africa and Brazil.
Messapicetus is an extinct genus of beaked whale from the Late Miocene. It currently holds two species, M. longirostris from the Tortonian of Italy and M. gregarius from the Pisco Formation of Peru. However, a third unnamed species is represented in the St. Marys Formation of Maryland known from fragmentary material. M. gregarius is sexually dimorphic, males having tusks which are hypothesized to have been used in intraspecific combat for mates as in extant (living) beaked whales.
Xhosacetus is a genus of Ziphiidae cetaceans with a single species, Xhosacetus hendeysi. It was classified from fossils found off the coast of the Kerguelen islands in 1,145 meter deep water.
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