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Daisy Stingray
The daisy stingray, ''Dasyatis margarita'', is a little-known species of stingray in the family Dasyatidae, found in shallow waters along the coast of West Africa. This species typically grows to across and has a rounded pectoral fin disc and (in adults) a wide band of dermal denticles over its back. It is characterized by a greatly enlarged, nacreous denticle in the middle of its back called a "pearl spine"; this feature is shared with the similar but much smaller pearl stingray (''D. margaritella''), which has often been confused with this species. The daisy stingray feeds mainly on crustaceans and exhibits aplacental viviparity, with litters of 1–4 young. Heavily pressured by fisheries and possibly habitat degradation, this once-common species is declining and has been assessed as Vulnerable by the International Union for Conservation of Nature (IUCN). Taxonomy British zoologist Albert Günther originally described the daisy stingray as ''Trygon margarita'', in his 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Günther
Albert Karl Ludwig Gotthilf Günther Fellow of the Royal Society, FRS, also Albert Charles Lewis Gotthilf Günther (3 October 1830 – 1 February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile taxonomist (after George Albert Boulenger) with more than 340 reptile species described. Early life and career Günther was born in Esslingen am Neckar, Esslingen in Swabia (Württemberg). His father was a ''Stiftungs-Commissar'' in Esslingen and his mother was Eleonora Nagel. He initially schooled at the Stuttgart Gymnasium. His family wished him to train for the ministry of the Lutheran Church for which he moved to the University of Tübingen. A brother shifted from theology to medicine, and he, too, turned to science and medicine at Tübingen in 1852. His first work was "''Ueber den Puppenzustand eines Distoma''". He graduated in medicine with an M.D. from Tübingen in 1858, the same year in which he pub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niger Stingray
The Niger stingray or smooth freshwater stingray (''Dasyatis garouaensis'') is a species of stingray in the family Dasyatidae, native to rivers in Nigeria and Cameroon. Attaining a width of , this species can be distinguished by its thin, almost circular pectoral fin disk, slightly projecting snout tip, and mostly smooth skin with small or absent dermal denticles. The Niger stingray feeds on aquatic insect larvae and is ovoviviparous. The long stinging spine on the tail of this ray can inflict a painful wound. It has been assessed as Critically Endangered by the International Union for Conservation of Nature (IUCN), as its numbers are declining in some areas and it faces heavy fishing pressure and habitat degradation. Taxonomy The original description of the Niger stingray was published by Alfred Stauch and M. Blanc in 1962, in the scientific journal ''Bulletin du Muséum National d'Histoire Naturelle (Série 2)''. The specific epithet ''garouaensis'' refers to the city of Garou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salinity
Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to ‰). Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water. A contour line of constant salinity is called an ''isohaline'', or sometimes ''isohale''. Definitions Salinity in rivers, lakes, and the ocean is conceptually simple, but technically challenging to define and measure precisely. Conceptually the salinity is the quantity of dissolved salt content of the water. Salts are compounds like sodium chloride, magnesium sulfate, potassium nitrate, and sodium bicarbonate which dissolve into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brackish Water
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root '' brak''. Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment (see article on shrimp farms). Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (‰), which is a specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine (ocean)
The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the world ocean is conventionally divided."Ocean." ''Merriam-Webster.com Dictionary'', Merriam-Webster, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line (intertida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angola
, national_anthem = "Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordinates = , largest_city = capital , official_languages = Portuguese , languages2_type = National languages , languages2 = , ethnic_groups = , ethnic_groups_ref = , ethnic_groups_year = 2000 , demonym = , government_type = Unitary dominant-party presidential republic , leader_title1 = President , leader_name1 = João Lourenço , leader_title2 = Vice President , leader_name2 = Esperança da CostaInvestidura do Pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mauritania
Mauritania (; ar, موريتانيا, ', french: Mauritanie; Berber languages, Berber: ''Agawej'' or ''Cengit''; Pulaar language, Pulaar: ''Moritani''; Wolof language, Wolof: ''Gànnaar''; Soninke language, Soninke:), officially the Islamic Republic of Mauritania ( ar, الجمهورية الإسلامية الموريتانية), is a sovereign country in West Africa. It is bordered by the Atlantic Ocean to the west, Western Sahara to Mauritania–Western Sahara border, the north and northwest, Algeria to Algeria–Mauritania border, the northeast, Mali to Mali–Mauritania border, the east and southeast, and Senegal to Mauritania–Senegal border, the southwest. Mauritania is the 11th-largest country in Africa and the 28th-largest in the world, and 90% of its territory is situated in the Sahara. Most of its population of 4.4 million lives in the temperate south of the country, with roughly one-third concentrated in the Capital city, capital and largest city, Nouakchott, loca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Democratic Republic Of The Congo
The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in Central Africa. It is bordered to the northwest by the Republic of the Congo, to the north by the Central African Republic, to the northeast by South Sudan, to the east by Uganda, Rwanda, and Burundi, and by Tanzania (across Lake Tanganyika), to the south and southeast by Zambia, to the southwest by Angola, and to the west by the South Atlantic Ocean and the Cabinda exclave of Angola. By area, it is the second-largest country in Africa and the 11th-largest in the world. With a population of around 108 million, the Democratic Republic of the Congo is the most populous officially Francophone country in the world. The national capital and largest city is Kinshasa, which is also the nation's economic center. Centered on the Congo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Senegal
Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: السنغال ''As-Sinighal'') officially the Republic of Senegal,; Wolof: ''Réewum Senegaal''; Pulaar : 𞤈𞤫𞤲𞤣𞤢𞥄𞤲𞤣𞤭 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Renndaandi Senegaali); Arabic: جمهورية السنغال ''Jumhuriat As-Sinighal'') is a country in West Africa, on the Atlantic Ocean coastline. Senegal is bordered by Mauritania to the north, Mali to the east, Guinea to the southeast and Guinea-Bissau to the southwest. Senegal nearly surrounds the Gambia, a country occupying a narrow sliver of land along the banks of the Gambia River, which separates Senegal's southern region of Casamance from the rest of the country. Senegal also shares a maritime border with Cape Verde. Senegal's economic and political capital is Dakar. Senegal is notably the westernmost country in the mainland of the Old World, or Afro-Eurasia. It owes its name to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearl
A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle) of a living shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carbonate (mainly aragonite or a mixture of aragonite and calcite) in minute crystalline form, which has deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes, known as baroque pearls, can occur. The finest quality of natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Because of this, ''pearl'' has become a metaphor for something rare, fine, admirable and valuable. The most valuable pearls occur spontaneously in the wild, but are extremely rare. These wild pearls are referred to as ''natural'' pearls. ''Cultured'' or ''farmed'' pearls from pearl oysters and freshwater mussels make up the majority of those currently sold. Imitation pearls are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the Roman Republic it became the dominant language in the Italian region and subsequently throughout the Roman Empire. Even after the fall of Western Rome, Latin remained the common language of international communication, science, scholarship and academia in Europe until well into the 18th century, when other regional vernaculars (including its own descendants, the Romance languages) supplanted it in common academic and political usage, and it eventually became a dead language in the modern linguistic definition. Latin is a highly inflected language, with three distinct genders (masculine, feminine, and neuter), six or seven noun cases (nominative, accusative, genitive, dative, ablative, and vocative), five declensions, four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
