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Pourtalesia Miranda
''Pourtalesia miranda'', commonly known as the wonderful sea urchin, is a species of sea urchin in the family Pourtalesiidae. It is found at abyssal depths in the Atlantic Ocean. Description The thin-shelled test is bottle-shaped, more than twice as long as it is wide, and with a marked rostrum at the posterior end. At the anterior end, the aboral ambulacrum is sunk, forming a funnel-like, forward-facing, nearly circular opening that leads to the peristome. The aboral surface has scattered low tubercles. ''Pourtalesia miranda'' differs from the otherwise similar '' Helgocystis'' in having the posterior ambulacral plate separate from the others. Adults are about long. The post-larval ''Pourtalesia miranda'' is at first radially symmetric, but as it grows, it becomes increasingly bilaterally symmetric. Growth is performed in two ways, by the creation of new plates at the apical end, and by the enlargement of existing plates by accretion around their margins. It is in the combina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Agassiz
Alexander Emmanuel Rodolphe Agassiz (December 17, 1835March 27, 1910), son of Louis Agassiz and stepson of Elizabeth Cabot Agassiz, was an American scientist and engineer. Biography Agassiz was born in Neuchâtel, Switzerland and immigrated to the United States with his parents, Louis and Cecile (Braun) Agassiz, in 1846. He graduated from Harvard University in 1855, subsequently studying engineering and chemistry, and taking the degree of Bachelor of Science at the Lawrence Scientific School of the same institution in 1857; in 1859 became an assistant in the United States Coast Survey. Thenceforward he became a specialist in marine ichthyology. Agassiz was elected a Fellow of the American Academy of Arts and Sciences in 1862. Up until the summer of 1866, Agassiz worked as assistant curator in the museum of natural history that his father founded at Harvard. E. J. Hulbert, a friend of Agassiz's brother-in-law, Quincy Adams Shaw, had discovered a rich copper lode known as the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dominance (ecology)
Ecological dominance is the degree to which one or several species have a major influence controlling the other species in their ecological community (because of their large size, population, productivity, or related factors) or make up more of the biomass. Most ecological communities are defined by their dominant species. *In many examples of wet woodland in western Europe, the dominant tree is alder ('' Alnus glutinosa''). *In temperate bogs, the dominant vegetation is usually species of ''Sphagnum'' moss. *Tidal swamps in the tropics are usually dominated by species of mangrove (''Rhizophoraceae'') *Some sea floor communities are dominated by brittle stars. *Exposed rocky shorelines are dominated by sessile organisms such as barnacles and limpets. See also * National Vegetation Classification, a system for classifying British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fauna Of The Atlantic Ocean
Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is ''funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoologists and paleontologists use ''fauna'' to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess Shale fauna". Paleontologists sometimes refer to a sequence of faunal stages, which is a series of rocks all containing similar fossils. The study of animals of a particular region is called faunistics. Etymology ''Fauna'' comes from the name Fauna, a Roman goddess of earth and fertility, the Roman god Faunus, and the related forest spirits called Fauns. All three words are cognates of the name of the Greek god Pan, and ''panis'' is the Greek equivalent of fauna. ''Fauna'' is also the word for a book that catalogues the animals in such a manner. The term was first used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holasteroida
Holasteroida is an order of irregular sea urchins. Characteristics These irregular sea urchins are characterized by a particularly marked bilateral symmetry, including for the apical system, which is highly elongated. In some contemporary abyssal groups such as Pourtalesiidae, some species are even bottle-shaped. The mouth (peristome) does not contain an Aristotle's lantern. The anus (periproct) has migrated towards the periphery of the test. The plastron is never amphisternous. Image:MHNT - Hemipneustes pyrenaicus - 1.jpg, Fossile of '' Hemipneustes pyrenaicus'' ( Hemipneustidae, Maastrichtian) Image:Echinosigra amphora.jpg, '' Echinosigra amphora'' ( Pourtalesiidae) This order seems to have appeared at the lower Cretaceous. List of families According to World Register of Marine Species : * Family Hemipneustidae (Lambert, 1917) †** genus '' Hemipneustes'' L. Agassiz, 1835 †** genus '' Medjesia'' Jeffery, 1997 †** genus '' Opisopneustes'' Gauthier, 1889 †... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byssus
A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilidae), and Dreissenidae. Filaments Byssus filaments are created by certain kinds of marine and freshwater bivalve mollusks, which use the byssus to attach themselves to rocks, substrates, or seabeds. In edible mussels, the inedible byssus is commonly known as the "beard", and is removed before cooking. Many species of mussels secrete byssus threads to anchor themselves to surfaces, with families including the Arcidae, Mytilidae, Anomiidae, Pinnidae, Pectinidae, Dreissenidae, and Unionidae. Mechanics The byssus, or byssal complex, is composed of multiple extracellular collagenous threads that are placed radially by the mussel from a central stem. Each thread is composed of three regions: a corrugated proximal region close to the mussel b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commensalism
Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit from each other; amensalism, where one is harmed while the other is unaffected; parasitism, where one is harmed and the other benefits, and parasitoidism, which is similar to parasitism but the parasitoid has a free-living state and instead of just harming its host, it eventually ends up killing it. The commensal (the species that benefits from the association) may obtain nutrients, shelter, support, or locomotion from the host species, which is substantially unaffected. The commensal relation is often between a larger host and a smaller commensal; the host organism is unmodified, whereas the commensal species may show great structural adaptation consistent with its habits, as in the remoras that ride attached to sharks and other fishes. Remo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminiferan
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell (called a "test") of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic), while a smaller number float in the water column at various depths (i.e., are planktonic), which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA. Foraminifera typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate in struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venus Flytrap Sea Anemone
The Venus flytrap sea anemone (''Actinoscyphia aurelia'') is a large sea anemone that superficially resembles a Venus flytrap. It closes its tentacles to capture prey or to protect itself. It is a deep ocean species. Distribution This sea anemone is found in muddy situations at bathyal depths in deep water canyons in the Gulf of Mexico. It has also been observed at several sites in the upwelling region off the coast of West Africa as well as the American Samoan region of the Pacific, but is uncommon elsewhere. Biology Venus flytrap sea anemone is a passive suspension feeder, and orients itself on its often slender column so that it faces the upwelling current. Its pedal disc is small, and its tentacles are short compared to the large, concave oral disc, which is funnel or mushroom-shaped. It extends its tentacles in two rows, one reflexed back and one sloping forward, and collects food particles as they drift past. Although usually considered sessile, the Venus flytrap sea an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mauritania
Mauritania (; ar, موريتانيا, ', french: Mauritanie; Berber: ''Agawej'' or ''Cengit''; Pulaar: ''Moritani''; Wolof: ''Gà nnaar''; 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 the north and northwest, Algeria to the northeast, Mali to the east and southeast, and Senegal to 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 and largest city, Nouakchott, located on the Atlantic coast. The country's name derives from the ancient Berber kingdom of Mauretania, located in North Africa within the ancient Maghreb. Berbers occupied what is now Mauritania ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of sea urchins are round and spiny, ranging in diameter from . Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals. Sea urchins are also used as food especially in Japan. Adult sea urchins have fivefold symmetry, but their pluteus larvae feature bilateral (mirror) symmetry, indicating that the sea urchin belongs to the Bilateria group of animal phyla, which also comprises the chordates and the arthropods, the annelids and the molluscs, and are found in every ocean and in every climate, from the tropics to the pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
