|
Sawback Angelshark
The sawback angelshark (''Squatina aculeata'') is an angelshark of the family Squatinidae It is one of rarest species of sharks known to date, and one of the three species of angelsharks that inhabits the Mediterranean. The Sawback angelshark lives in sandy and muddy bottoms of the ocean at depths of 30-500m. Measurements Their size at birth ranges from 30 to 35 cm. As adults, female measurements range from 137 to 143 cm, while males range from 120 to 122 cm. Their relative weight based on the size of the shark for males is between 12.7 kg and 24.0 kg. In females, they weigh anywhere from 22 to 32 kg. The females grow to be larger than the males because they need to be able to carry and support their young. Development The development of the males was measured in three stages, juvenile, subadult and adult. The juvenile males had short and flexible claspers and the testes were membranous and barely developed. The subadult males showed changes in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georges Cuvier
Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French natural history, naturalist and zoology, zoologist, sometimes referred to as the "founding father of paleontology". Cuvier was a major figure in natural sciences research in the early 19th century and was instrumental in establishing the fields of comparative anatomy and paleontology through his work in comparing living animals with fossils. Cuvier's work is considered the foundation of vertebrate paleontology, and he expanded Linnaean taxonomy by grouping classes into phylum, phyla and incorporating both fossils and living species into the classification. Cuvier is also known for establishing extinction as a fact—at the time, extinction was considered by many of Cuvier's contemporaries to be merely controversial speculation. In his ''Essay on the Theory of the Earth'' (1813) Cuvier proposed that now-extinct species had been wiped out by periodic catastrophi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angelshark
The angelsharks are a group of sharks in the genus ''Squatina'' of the family Squatinidae. They commonly inhabit sandy seabeds close to in depth. Many species are now classified as critically endangered by the International Union for Conservation of Nature. Once common over large areas of the Northeast Atlantic from Norway, Sweden, Morocco, and the Canary Islands, to the Mediterranean and Black Seas, there is now significant fishing pressure which has resulted in significant population decline. Squatinidae are unusual in having flattened bodies and broad pectoral fins that give them a strong resemblance to rays. This genus is the only one in its family and order Squatiniformes. They occur worldwide in temperate and tropical seas. Most species inhabit shallow temperate or tropical seas, but a few species inhabit deeper water, down to . Angel sharks are sometimes called monkfish, although this name is also applied to members of the genus ''Lophius''. While some species occur ove ... [...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] |
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red Lists are produced by countries or organizations, which assess the risk of extinction to species within a political management unit. The aim of the IUCN Red List is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to reduce species extinction. According to IUCN the formally stated goals of the Red List are to provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overexploitation
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term applies to natural resources such as water aquifers, grazing pastures and forests, wild medicinal plants, fish stocks and other wildlife. In ecology, overexploitation describes one of the five main activities threatening global biodiversity. Ecologists use the term to describe populations that are harvested at an unsustainable rate, given their natural rates of mortality and capacities for reproduction. This can result in extinction at the population level and even extinction of whole species. In conservation biology, the term is usually used in the context of human economic activity that involves the taking of biological resources, or organisms, in larger numbers than their populations can withstand. The term is also used and defined some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonard Compagno
Leonard Joseph Victor Compagno is an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization (FAO) of the United Nations. Compagno was mentioned in the credits of the 1975 film ''Jaws'' along with the National Geographic Society. Career *Ph.D, Stanford University, 1979 *Adjunct professor, San Francisco State University, 1979 to 1985 *Curator of Fishes in the Division of Life Sciences and Head of the Shark Research Centre (SRC), Iziko Museums, Cape Town *Director, Shark Research Institute(SRI) Selected bibliography *Compagno, L.J.V., 1979. ''Carcharhinoid sharks: morphology, systematics and phylogeny''. Unpublished Ph. D. Thesis, Stanford University, 932 p. Available from University Microfilms International, Ann Arbor, Michigan. *Leonard Compagno, 1984a. FAO The Food and Agriculture Organization of the United Nati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of The Mediterranean Sea
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Fauna Of West Africa
Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (other) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * Marines, a naval-based infantry force ** United States Marine Corps ** Royal Marines of the UK ** Brazilian Marine Corps ** Spanish Marine Infantry ** Fusiliers marins (France) ** Indonesian Marine Corps ** Republic of China Marine Corps ** Republic of Korea Marine Corps ** Royal Thai Marine Corps *"Marine" also means "navy" in several languages: ** Austro-Hungarian Navy () ** Belgian Navy (, , ) ** Royal Canadian Navy () *** Provincial Marine (1796–1910), a predecessor to the Royal Canadian Navy ** Navy of the Democratic Republic of the Congo () ** Royal Danish Navy () ** Finnish Navy (, ) ** French Navy () ** Gabonese Navy () ** German Navy () ** Royal Moroccan Navy () ** Royal Netherlands Navy () ** Swedish Navy () Places * Marin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1829
Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a vertebrate, true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed placodermi, external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
