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Hector's Beaked Whale
Hector's beaked whale (''Mesoplodon hectori''), 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. Some data supposedly referring to this species, especially juveniles and males, turned out to be based on the misidentified specimens of Perrin's beaked whale - especially since the adult male of Hector's beaked whale was only more recently described. Taxonomy The English taxonomist John Edward Gray first named the species ''Berardius hectori'' in 1871, based on a specimen (a male) collected in Titahi Bay, New Zealand in January, 1866. The following year, 1872, English anatomist William Henry Flower placed it in the genus ''Mesoplodon'', while in 1873, Scottish scientist James Hector assigned the same specimen to the species ''M. knoxi''. The species remained in the genus ''Mesoplodon'' until 1962, when Charles McCann, a vert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Edward Gray
John Edward Gray, FRS (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for a zoological name. Gray was keeper of zoology at the British Museum in London from 1840 until Christmas 1874, before the natural history holdings were split off to the Natural History Museum. He published several catalogues of the museum collections that included comprehensive discussions of animal groups and descriptions of new species. He improved the zoological collections to make them amongst the best in the world. Biography Gray was born in Walsall, but his family soon moved to London, where Gray studied medicine. He assisted his father in writing ''The Natural Arrangement of British Plants'' (1821). After being blackballed by the Linnean Society of London, Gray shifted his interest from botany to zoology. He began his zoologica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beaked Whale
Beaked whales (systematic name Ziphiidae) are a family 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 24 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. Reports emerged in late 2020 of the possible discovery of a new beaked whale species off the coast of Mexico, the taxonomy of which had not been determined . Physical characteristics Beaked whales are moderate in size, ranging from and weighing from . Their key distinguishing feature is the presence of a 'beak', somewhat similar to many dolphins. Other distinctive features include a pair of converging grooves under the throat, and the absence of a notch in the tail fluke. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atavism
In biology, an atavism is a modification of a biological structure whereby an ancestral genetic trait reappears after having been lost through evolutionary change in previous generations. Atavisms can occur in several ways; one of which is when genes for previously existing phenotypic features are preserved in DNA, and these become expressed through a mutation that either knocks out the dominant genes for the new traits or makes the old traits dominate the new one. A number of traits can vary as a result of shortening of the fetal development of a trait (neoteny) or by prolongation of the same. In such a case, a shift in the time a trait is allowed to develop before it is fixed can bring forth an ancestral phenotype. Atavisms are often seen as evidence of evolution. In social sciences, atavism is the tendency of reversion. For example, people in the modern era reverting to the ways of thinking and acting of a former time. The word ''atavism'' is derived from the Latin ''atavus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fang
A fang is a long, pointed tooth. In mammals, a fang is a modified maxillary tooth, used for biting and tearing flesh. In snakes, it is a specialized tooth that is associated with a venom gland (see snake venom). Spiders also have external fangs, which are part of the chelicerae. Fangs are most common in carnivores or omnivores, but some herbivores, such as fruit bats, have them as well. They are generally used to hold or swiftly kill prey, such as in large cats. Omnivorous animals, such as bears, use their fangs when hunting fish or other prey, but they are not needed for consuming fruit. Some apes also have fangs, which they use for threats and fighting. However, the relatively short canines of humans are not considered to be fangs. Fangs in religion, mythology and legend Certain mythological and legendary creatures such as dragons, gargoyles and yakshas are commonly depicted with prominent fangs. The fangs of vampires are one of their defining characteristics. The iconogra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories by area, and second smallest state by population. It has a total of 1.8 million people. Its population is the second most highly centralised in Australia, after Western Australia, with more than 77 percent of South Australians living in the capital Adelaide, or its environs. Other population centres in the state are relatively small; Mount Gambier, the second-largest centre, has a population of 33,233. South Australia shares borders with all of the other mainland states, as well as the Northern Territory; it is bordered to the west by Western Australia, to the north by the Northern Territory, to the north-east by Queensland, to the east by New South Wales, to the south-east by Victoria, and to the south by the Great Australian Bight.M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adelaide
Adelaide ( ) is the capital city of South Australia, the state's largest city and the fifth-most populous city in Australia. "Adelaide" may refer to either Greater Adelaide (including the Adelaide Hills) or the Adelaide city centre. The demonym ''Adelaidean'' is used to denote the city and the residents of Adelaide. The Traditional Owners of the Adelaide region are the Kaurna people. The area of the city centre and surrounding parklands is called ' in the Kaurna language. Adelaide is situated on the Adelaide Plains north of the Fleurieu Peninsula, between the Gulf St Vincent in the west and the Mount Lofty Ranges in the east. Its metropolitan area extends from the coast to the foothills of the Mount Lofty Ranges, and stretches from Gawler in the north to Sellicks Beach in the south. Named in honour of Queen Adelaide, the city was founded in 1836 as the planned capital for the only freely-settled British province in Australia. Colonel William Light, one of Adelaide's foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Australian Museum
The South Australian Museum is a natural history museum and research institution in Adelaide, South Australia, founded in 1856 and owned by the Government of South Australia. It occupies a complex of buildings on North Terrace in the cultural precinct of the Adelaide Parklands. Plans are under way to move much of its Australian Aboriginal cultural collection (the largest in the world), into a new National Gallery for Aboriginal Art and Cultures. History 19th century There had been earlier attempts at setting up mechanics' institutes in the colony, but they struggled to find buildings which could hold their library collections and provide spaces for lectures and entertainments. In 1856, the colonial government promised support for all institutes, in the form of provision the first government-funded purpose-built cultural institution building. The South Australian Institute, incorporating a public library and a museum, was established in 1861 in the rented premises of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisakis
''Anisakis'' (a·nuh·saa·keez) is a genus of parasitic nematodes that have life cycles involving fish and marine mammals. They are infective to humans and cause anisakiasis. People who produce immunoglobulin E in response to this parasite may subsequently have an allergic reaction, including anaphylaxis, after eating fish infected with ''Anisakis'' species. Etymology The genus ''Anisakis'' was defined in 1845 by Félix Dujardin as a subgenus of the genus ''Ascaris'' Linnaeus, 1758. Dujardin did not make explicit the etymology, but stated that the subgenus included the species in which the males have unequal spicules ("''mâles ayant des spicules inégaux''"); thus, the name ''Anisakis'' is based on ''anis-'' (Greek prefix for different) and ''akis'' (Greek for spine or spicule). Two species were included in the new subgenus, ''Ascaris'' (''Anisakis'') ''distans'' Rudolphi, 1809 and ''Ascaris'' (''Anisakis'') simplex Rudolphi, 1809. Life cycle ''Anisakis'' species have c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broad range of environments. Less formally, they are categorized as Helminths, but are taxonomically classified along with Arthropod, arthropods, Tardigrade, tardigrades and other moulting animalia, animals in the clade Ecdysozoa, and unlike platyhelminthe, flatworms, have tubular digestion, digestive systems with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species described to date vary by author and may change rapidly over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (anatomy)
The lens, or crystalline lens, is a transparent biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, it functions to change the focal length of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. This adjustment of the lens is known as '' accommodation'' (see also below). Accommodation is similar to the focusing of a photographic camera via movement of its lenses. The lens is flatter on its anterior side than on its posterior side. In humans, the refractive power of the lens in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power. Structure The lens is part of the anterior segment of the human eye. In front of the lens is the iris, which regulates the amount of light entering into the eye. The lens is suspended in place by the suspensory ligament of the lens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isistius
''Isistius'' is a genus of Squaliformes, dogfish sharks in the family (biology), family Dalatiidae. They are commonly known as cookiecutter sharks. Members of the genus are known for their unusual behaviour and dentition. Species *''Isistius brasiliensis'' Jean René Constant Quoy, Quoy & Joseph Paul Gaimard, Gaimard, 1824 (cookiecutter shark) *''Isistius plutodus'' Jack Garrick, Garrick & Stewart Springer, S. Springer, 1964 (largetooth cookiecutter shark) *†''Isistius triangulus Probst, 1879 *†''Isistius trituratus Winkler, 1876 Habits The cookiecutter sharks, or cigar sharks, are unusual in the manner in which they replace their teeth. Instead of replacing teeth singly as they get damaged or lost, for example in hunting, such sharks replace the whole set. They can repeat such replacement throughout their lifetimes. Cookiecutter sharks often attack large shoals of fish, but have been known to circle fishing vessels to get an easy meal. They are particularly notorious for b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cookiecutter Shark
The cookiecutter shark (''Isistius brasiliensis''), also called the cigar shark, is a species of small squaliform shark in the family Dalatiidae. This shark occurs in warm, oceanic waters worldwide, particularly near islands, and has been recorded as deep as . It migrates vertically up to every day, approaching the surface at dusk and descending with the dawn. Reaching only in length, the cookiecutter shark has a long, cylindrical body with a short, blunt snout, large eyes, two tiny spineless dorsal fins, and a large caudal fin. It is dark brown, with light-emitting photophores covering its underside except for a dark "collar" around its throat and gill slits. The name "cookiecutter shark" refers to its feeding habit of gouging round plugs, as if cut out with a cookie cutter, out of larger animals. Marks made by cookiecutter sharks have been found on a wide variety of marine mammals and fishes, as well as on submarines, undersea cables, and even human bodies. It also consume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
