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Dilemma (bivalve)
''Dilemma'' is a genus of marine bivalves of the family Poromyidae. The genus is remarkable for encompassing predators of isopods and ostracods, unusual for sessile molluscs. One species is known from the western Atlantic Ocean (Straits of Florida) and three from across the Pacific. Specimens have been found at depths between . The name of the genus refers to the dilemma that the author of the new genus faced while diagnosing it. Species There are four species: * ''Dilemma frumarkernorum'' Leal, 2008 * ''Dilemma inexpectatum'' (Crozier, 1966) * ''Dilemma japonicum'' Sasaki & Leal, 2008 * ''Dilemma spectralis A dilemma ( grc-gre, δίλημμα "double proposition") is a problem offering two possibilities, neither of which is unambiguously acceptable or preferable. The possibilities are termed the ''horns'' of the dilemma, a clichéd usage, but distin ...'' Leal, 2008 References Poromyidae Bivalve genera {{bivalve-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sessility (zoology)
Sessility is the biological property of an organism describing its lack of a means of self-locomotion. Sessile organisms for which natural ''motility'' is absent are normally immobile. This is distinct from the botanical concept of sessility, which refers to an organism or biological structure attached directly by its base without a stalk. Sessile organisms can move via external forces (such as water currents), but are usually permanently attached to something. Organisms such as corals lay down their own substrate from which they grow. Other sessile organisms grow from a solid such as a rock, dead tree trunk, or a man-made object such as a buoy or ship's hull. Mobility Sessile animals typically have a motile phase in their development. Sponges have a motile larval stage and become sessile at maturity. Conversely, many jellyfish develop as sessile polyps early in their life cycle. In the case of the cochineal, it is in the nymph stage (also called the crawler stage) that the co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilemma Spectralis
A dilemma ( grc-gre, δίλημμα "double proposition") is a problem offering two possibilities, neither of which is unambiguously acceptable or preferable. The possibilities are termed the ''horns'' of the dilemma, a clichéd usage, but distinguishing the dilemma from other kinds of predicament as a matter of usage. Terminology The term ''dilemma'' is attributed by Gabriel Nuchelmans to Lorenzo Valla in the 15th century, in later versions of his logic text traditionally called ''Dialectica''. Valla claimed that it was the appropriate Latin equivalent of the Greek ''dilemmaton''. Nuchelmans argued that his probable source was a logic text of c.1433 of George of Trebizond. He also concluded that Valla had reintroduced to the Latin West a type of argument that had fallen into disuse. Valla's neologism did not immediately take hold, preference being given to the established Latin term ''complexio'', used by Cicero, with ''conversio'' applied to the upsetting of dilemmatic reaso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilemma Inexpectatum
''Dilemma inexpectatum'' is a minute species of deepwater cockle, a marine bivalve mollusc in the family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ... Cardiidae. References Cardiidae Molluscs of the Pacific Ocean Bivalves of New Zealand Molluscs described in 1966 {{Cardiidae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilemma Frumarkernorum
A dilemma ( grc-gre, δίλημμα "double proposition") is a problem offering two possibilities, neither of which is unambiguously acceptable or preferable. The possibilities are termed the ''horns'' of the dilemma, a clichéd usage, but distinguishing the dilemma from other kinds of predicament as a matter of usage. Terminology The term ''dilemma'' is attributed by Gabriel Nuchelmans to Lorenzo Valla in the 15th century, in later versions of his logic text traditionally called ''Dialectica''. Valla claimed that it was the appropriate Latin equivalent of the Greek ''dilemmaton''. Nuchelmans argued that his probable source was a logic text of c.1433 of George of Trebizond. He also concluded that Valla had reintroduced to the Latin West a type of argument that had fallen into disuse. Valla's neologism did not immediately take hold, preference being given to the established Latin term ''complexio'', used by Cicero, with ''conversio'' applied to the upsetting of dilemmatic reaso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Straits Of Florida
The Straits of Florida, Florida Straits, or Florida Strait ( es, Estrecho de Florida) is a strait located south-southeast of the North American mainland, generally accepted to be between the Gulf of Mexico and the Atlantic Ocean, and between the Florida Keys (U.S.) and Cuba. It is 93 mi (150 km) wide at the narrowest point between Key West and the Cuban shore, and has been sounded to a depth of 6,000 feet (1,800 m). The strait carries the Florida Current, the beginning of the Gulf Stream, from the Gulf of Mexico. Oil and gas Five wells were drilled in state waters south of the Florida Keys from 1947 to 1962. Gulf Oil drilled three wells in federal waters south of the Florida Keys in 1960 and 1961. All the wells were dry holes. The boundary between the Exclusive Economic Zones of the US and Cuba is halfway between Cuba and Florida, as determined by the 1977 Cuba–United States Maritime Boundary Agreement. Offshore Cuba Cuba has three producing offshore oil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostracods
Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typically around in size, but varying from in the case of '' Gigantocypris''. Their bodies are flattened from side to side and protected by a bivalve-like, chitinous or calcareous valve or "shell". The hinge of the two valves is in the upper (dorsal) region of the body. Ostracods are grouped together based on gross morphology. While early work indicated the group may not be monophyletic and early molecular phylogeny was ambiguous on this front, recent combined analyses of molecular and morphological data found support for monophyly in analyses with broadest taxon sampling. Ecologically, marine ostracods can be part of the zooplankton or (most commonly) are part of the benthos, living on or inside the upper layer of the sea floor. While Myo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus (biology)
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus '' Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should clearly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isopods
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax. Isopods have various feeding methods: some eat dead or decaying plant and animal matter, others are grazers, or filter feeders, a few are predators, and some are internal or external parasites, mostly of fish. Aquatic species mostly live on the seabed or bottom of freshwater bodies of water, but some taxa can swim for a short distance. Terrestrial forms move around by crawling and tend to be found in cool, moist places. Some species are able to roll themselves into a ball as a defense mechanism or to conserve moisture. There are over 10,000 identified species of isopod worldwide, with around ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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