|
Albicetus
''Albicetus'' is a genus of stem-sperm whales that lived during the Miocene Epoch, around 15 million years ago, and was discovered in Santa Barbara, California in 1909. It was categorized for decades as belonging to a group of extinct walruses erroneously thought to be sperm whales. It was named ''Albicetus'', meaning "white whale", is a reference to the leviathan in Herman Melville's classic 1851 novel ''Moby-Dick''. Taxonomy Etymology The genus ''Albicetus'' derives from the Latin ''albus'' "white" and ''cetus'' "whale", and so literally means "white whale". It was named in reference to the antagonist Moby Dick from Herman Melville's novel ''Moby-Dick''. This reference was done both in honor of Melville and as a reference to the most notable traits of the Moby Dick–including an "unwonted magnitude", light color, and a crooked and deformed lower jaw–which coincidentally also describe the traits found in the ''Albicetus oxymycterus'' holotype specimen (the fossils themselv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macroraptorial Sperm Whale
Macroraptorial sperm whales were highly predatory whales of the sperm whale superfamily (Physeteroidea) of the Miocene epoch (geology), epoch that hunted large marine mammals, including other whales, using their large teeth. They consist of five genera: ''Acrophyseter'', ''Albicetus'', ''Brygmophyseter'', ''Livyatan'', and ''Zygophyseter''. All species are known by at least a skull, and are informally grouped without a family (biology), family designation. They were all likely the apex predator of their habitats, comparable to the modern day killer whale (''Orcinus orca''), and achieved great lengths, with one species–''Livyatan''–measuring about . Discovery ''Zygophyseter'' was discovered in the Pietra Leccese Formation in Italy from a skull, teeth, and vertebrae; ''Brygmophyseter'' was discovered in the Bessho Formation in Japan from a nearly-complete skeleton; and ''Acrophyseter'' and ''Livyatan'' both originate from the Pisco Formation in Peru and are known by only a skull. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ontocetus
''Ontocetus'' is an extinct genus of walrus, an aquatic carnivoran of the family Odobenidae, endemic to coastal regions of the southern North Sea and the southeastern coastal regions of the U.S. during the Miocene-Pleistocene. It lived from 13.6 mya—300,000 years ago, existing for approximately . Taxonomy The type species, ''Ontocetus emmonsi'', was named by Joseph Leidy in 1859 on the basis of a single tusk-like tooth (USNM 329064) collected by Ebenezer Emmons from the early Pliocene (Zanclean) Yorktown Formation of North Carolina. In the meantime, marine mammals fossils were being unearthed in Neogene deposits in the vicinity of Antwerp, Belgium as well as Suffolk, England. One of these fossils was identified as an odobenid and named ''Alachtherium cretsii.'' in 1867. An isolated tooth (RBINS 2892) was named ''Trichechodon koninckii'' in 1871. The fossils from Suffolk were named ''Trichechodon huxleyi'' in 1865. For decades, however, ''Ontocetus'' was tossed aside as a phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scaldicetus
''Scaldicetus'' is an extinct genus of highly predatory macroraptorial sperm whale. Although widely used for a number of extinct physeterids with primitive dental morphology consisting of enameled teeth, ''Scaldicetus'' as generally recognized appears to be a wastebasket taxon filled with more-or-less unrelated primitive sperm whales. Taxonomy ''Scaldicetus'' is known from the Miocene to Pleistocene deposits of Western Europe, the U.S. (California, Florida, Maryland, Virginia), Baja Peninsula, Peru, New South Wales, and Japan. However, ''Scaldicetus'' is probably a grade taxon, and fossil teeth assigned to it (largely due to the lack of distinguishing characteristics in fossil teeth alone) probably represent more-or-less unrelated sperm whales united by their primitive characteristics rather than actual ancestry. Consequently, this would inflate the genus's distribution. The name ''Scaldicetus caretti'' was coined in 1867 from numerous sperm whale teeth collected in Neogene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brygmophyseter
''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 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 (often shortened to "raptorial") 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 '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Langhian
The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene Epoch/ Series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma (million years ago) during the Middle Miocene.GeoWhen (2007) The Langhian was a continuing warming period defined by Lorenzo Pareto in 1865, it was originally established in the Langhe area north of Ceva in northern Italy, hence the name. The Langhian is preceded by the Burdigalian and followed by the Serravallian Stage. Stratigraphic definition The base of the Langhian is defined by the first appearance of foraminifer species ''Praeorbulina glomerosa'' and is also coeval with the top of magnetic chronozone C5Cn.1n. A GSSP for the Langhian Stage was not yet established in 2009. The top of the Langhian Stage (the base of the Serravallian Stage) is at the first occurrence of fossils of the nanoplankton species ''Sphenolithus heteromorphus'' and is located in magnetic chronozone C5ABr. The Langhian is coeval wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygophyseter
''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 (often shortened to "raptorial") also including ''Brygmophyseter'', ''Acrophyseter'', and ''Livyatan''. It probably grew to be around 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 (''Physeter macrocephalus'') lacks. It also had a beak, the ability to echolocate prey, and could have probably swum faster than the modern-day sperm whale which can reach . 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 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Livyatan
''Livyatan'' is an extinct genus of macroraptorial sperm whale containing one known species: ''L. melvillei''. The genus name was inspired by the biblical sea monster Leviathan, and the species name by Herman Melville, the author of the famous novel ''Moby-Dick'' about a white bull sperm whale. It is mainly known from the Pisco Formation of Peru during the Tortonian stage of the Miocene epoch, about 9.9–8.9 million years ago (mya); however, finds of isolated teeth from other locations such as Chile, Argentina, South Africa, and Australia imply that either it or a close relative survived into the Pliocene, around 5mya, and was present throughout the Southern Hemisphere. It was a member of a group of macroraptorial sperm whales (or "raptorial sperm whales") and was probably an apex predator, preying on whales, seals, and so forth. Characteristically of raptorial sperm whales, ''Livyatan'' had functional, enamel-coated teeth on the upper and lower jaws, as well as several fea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrophyseter
''Acrophyseter'' is a genus of extinct sperm whales that lived in the Late Miocene off the coast of Peru comprising two species: ''A. deinodon'' and ''A. robustus''. It is part of a group of macroraptorial sperm whales which all shared several features for the purpose of hunting large prey, such as deeply-rooted and thick teeth. ''Acrophyseter'' measured , making it the smallest raptorial sperm whale. Because of its short pointed snout, and its strong curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales. Discovery The genus ''Acrophyseter'' houses two species. The type species, ''A. deinodon'', was discovered in the Sud-Sacaco locality of the Pisco Formation in Peru, dating back to the Tortonian–Messinian stages of the Miocene around 8.5–6.7 million years ago (mya); the holotype specimen, MNHN SAS 1626, represents a mature individual and consists of a skull and jaw with most of the teeth intact. The second species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Enamel
Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, cementum, and dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. Calcium hardens the tooth enamel. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed on the tooth while the tooth develops wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sperm Whale
The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale family, along with the pygmy sperm whale and dwarf sperm whale of the genus ''Kogia''. The sperm whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. Females and young males live together in groups, while mature males (bulls) live solitary lives outside of the mating season. The females cooperate to protect and nurse their young. Females give birth every four to twenty years, and care for the calves for more than a decade. A mature sperm whale has few natural predators, although calves and weakened adults are sometimes killed by pods of killer whales (orcas). Mature males average in length, with the head representing up to one-third of the animal's length. Plunging to , it is the third d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wastebasket Taxon
Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined by either their designated members' often superficial similarity to each other, or their ''lack'' of one or more distinct character states or by their ''not'' belonging to one or more other taxa. Wastebasket taxa are by definition either paraphyletic or polyphyletic, and are therefore not considered valid taxa under strict cladistic rules of taxonomy. The name of a wastebasket taxon may in some cases be retained as the designation of an evolutionary grade, however. The term was coined in a 1985 essay by Steven Jay Gould. Examples There are many examples of paraphyletic groups, but true "wastebasket" taxa are those that are known not to, and perhaps not intended to, represent natural groups, but are nevertheless used as convenient gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odobenidae
Odobenidae is a family of pinnipeds. The only living species is the walrus (''Odobenus rosmarus''). In the past, however, the group was much more diverse, and includes more than a dozen fossil genera. Taxonomy All genera, except ''Odobenus'', are extinct. *†''Archaeodobenus'' *†''Prototaria'' *†''Proneotherium'' *†''Nanodobenus'' *†''Neotherium'' *†''Imagotaria'' *†'' Kamtschatarctos'' *†''Pelagiarctos'' *†'' Pontolis'' *†'' Pseudotaria'' *†''Titanotaria'' *Clade Neodobenia **†'' Gomphotaria'' **Subfamily Dusignathinae ***†'' Dusignathus'' **Subfamily Odobeninae ***†''Aivukus'' ***†'' Ontocetus'' ***†'' Pliopedia'' ***†'' Protodobenus'' ***†'' Valenictus'' ***''Odobenus The walrus (''Odobenus rosmarus'') is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the fa ...'' In re-analyzing ''Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
