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Shortspine Spurdog
The shortspine spurdog (''Squalus mitsukurii'') is a dogfish, a member of the family Squalidae, found on continental shelves off Japan in temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ... waters, from the surface to 950 m. Its length is up to 75 cm. Taxonomy The shortspine dogfish was once seen as a circumglobal species by many authors, including Compagno (1984) and Last & Stevens (1994). However, a series on papers published since 2007 have shown that a number of species synonymized with ''S. mitsukurii'' are distinct, and that the Hawaiian population of ''S. mitsukurii'' represent a distinct species, the Hawaiian spurdog.Daly-Engel TS, Koch A, Anderson JM, Cotton CF, Grubbs RD (2018) Description of a new deep-water dogfish shark from Hawaii, with comments on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Starr Jordan
David Starr Jordan (January 19, 1851 – September 19, 1931) was the founding president of Stanford University, serving from 1891 to 1913. He was an ichthyologist during his research career. Prior to serving as president of Stanford University, he had served as president of Indiana University from 1884 to 1891. Starr was also a strong supporter of eugenics, and his published views expressed a fear of "race-degeneration" and asserted that cattle and human beings are "governed by the same laws of selection". He was an antimilitarist since he believed that war killed off the best members of the gene pool, and he initially opposed American involvement in World War I. Early life and career Jordan was born in Gainesville, New York, and grew up on a farm in upstate New York. His parents made the unorthodox decision to educate him at a local girls' high school. His middle name, Starr, does not appear in early census records, and was apparently self-selected; he had begun using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Otterbein Snyder
John Otterbein Snyder (August 14, 1867 – August 19, 1943) was an American ichthyologist and professor of zoology at Stanford University. History As a student he met David Starr Jordan who inspired him to enter zoology. He eventually became a zoology instructor at Stanford University and served there from 1899 until 1943. He went on several major collecting expeditions aboard the in the early 1900s and organized the U.S. National Museum's fish collection in 1925. The same year he also declined the directorship there so he could return to Stanford. He was a long-term member of the California Academy of Sciences and worked for the California Bureau of Fisheries. He wrote many articles and papers as well as describing several new species of sharks. San Francisco Bay In 1905, Snyder, then Assistant Professor of Zoology at Stanford, published ''Notes on the fishes of the streams flowing into San Francisco Bay'' in ''Report of the Commissioner of Fisheries to the Secretary of Comme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squaliformes
The Squaliformes are an order (biology), order of sharks that includes about 126 species in seven families. Members of the order have two dorsal fins, which usually possess spines, they usually have a sharp head, no anal fin or nictitating membrane, and five to seven gill slits. In most other respects, however, they are quite variable in form and size. Most species of the squaliform order live in saltwater or brackish water. They are found worldwide, from northern to tropical waters, and from shallow coastal seas to the open ocean. All members of the family Eptomeridae and Dalatiidae and ''Zameus squamulosus'' possess photophores, luminous organs, and exhibit intrinsic bioluminescence. Bioluminescence evolved once in Squaliformes, approximately 111–153 million years ago, and helped the Squaliformes radiate and adapt to the deep sea. The common ancestor of Dalatiidae, Etmopteridae, Somniosidae, and Oxynotidae possessed a luminous organ and used bioluminescence for camouf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family ( la, familia, plural ') is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, but in plants, they can be characterized on the basis of both vegetative and reproductive features of plant species. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squalidae
Squalidae, more commonly known as dogfish, dog sharks, or spiny dogfish, are one of several families of sharks categorized under Squaliformes, making it the second largest order of sharks, numbering 119 species across 7 families. Having earned their name after a group of fishermen reportedly observed the species chasing down smaller fish in dog-like packs, dogfish have slender, streamlined bodies, usually more compact in comparison to other species, and a pointed snout. Dogfish likewise have two dorsal fins, each with smooth spines, but no anal fin, and their skin is generally rough to the touch. As the species reaches adulthood, males usually measure a maximum of 39 inches (990 mm), while females typically measure 49 inches (1,200 mm) long. The species therefore exhibits female-dominant sexual dimorphism. Dogfish sharks have slate-gray or gray-brown skin with white dots that becomes paler (almost white) around the belly region. These sharks are characterized by teeth i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Shelf
A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island is known as an ''insular shelf''. The continental margin, between the continental shelf and the abyssal plain, comprises a steep continental slope, surrounded by the flatter continental rise, in which sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope. Extending as far as 500 km (310 mi) from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rise's gradient is intermediate between the gradients of the slope and the shelf. Under the United Nations Convention on the Law of the Sea, the name continental shelf was given a legal definition as the stretch of the seabed adjacent to the shores of a par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small and usually only have precipitation changes. In temperate climates, not only do latitudinal positions influence temperature changes, but sea currents, prevailing wind direction, continentality (how large a landmass is) and altitude also shape temperate climates. The Köppen climate classification defines a climate as "temperate" C, when the mean temperature is above but below in the coldest month to account for the persistency of frost. However, other climate classifications set the minimum at . Zones and climates The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arctic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hawaiian Spurdog
''Squalus hawaiiensis'', the Hawaiian spurdog, is a dogfish, a member of the family Squalidae, found in waters surrounding the Hawaiian Islands, from the surface to 950 m. Its length is up to 75 cm. Taxonomy ''Squalus hawaiiensis'' was once lumped with the shortspine spurdog The shortspine spurdog (''Squalus mitsukurii'') is a dogfish, a member of the family Squalidae, found on continental shelves off Japan in temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to ..., but morphological and genetic data showed that the Hawaiian population was distinct from ''S. mitsukurii'' individuals from Japan to be considered a distinct species.Daly-Engel TS, Koch A, Anderson JM, Cotton CF, Grubbs RD (2018) Description of a new deep-water dogfish shark from Hawaii, with comments on the Squalus mitsukurii species complex in the West Pacific. ZooKeys 798: 135-157. https://doi.org/10.3897/zookeys.798.28375 References {{Taxonbar, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squalus
''Squalus'' is a genus of dogfish sharks in the family Squalidae. Commonly known as spurdogs, these sharks are characterized by smooth dorsal fin spines, teeth in upper and lower jaws similar in size, caudal peduncle with lateral keels; upper precaudal pit usually present, and caudal fin without subterminal notch. In spurdogs, the hyomandibula (the bone connecting the braincase to the jaws) is oriented at a right angle to the neurocranium, while in other sharks, the hyomandibula runs more parallel to the body. This led some to think that the upper jaw of ''Squalus'' would not be as protractile as the jaws of other sharks. However, a study that compared different jaw suspension types in sharks showed that this is not the case and that ''Squalus'' is quite capable of protruding its upper jaw during feeding.Wilga, C.D., Motta, P.J. & Sanford, C.P. (2007): Evolution and ecology of feeding in elasmobranchs. ''Integrative and Comparative Biology, 47 (1): 55-69.'' The name comes from '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
