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Clupeoid Fish
Clupeiformes is the order of ray-finned fish that includes the herring family, Clupeidae, and the anchovy family, Engraulidae and sardines. The group includes many of the most important forage and food fish. Clupeiformes are physostomes, which means that their gas bladder has a pneumatic duct connecting it to the gut. They typically lack a lateral line, but still have the eyes, fins and scales that are common to most fish, though not all fish have these attributes. They are generally silvery fish with streamlined, spindle-shaped bodies, and they often school. Most species eat plankton which they filter from the water with their gill rakers. The former order of Isospondyli was subsumed mostly by Clupeiformes, but some isospondylous fishes (isospondyls) were assigned to Osteoglossiformes, Salmoniformes, Cetomimiformes, etc. Their sister group were the extinct Ellimmichthyiformes, which were dominant throughout much of the Cretaceous and into the Paleogene, and often coexisted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded by the Hauterivian and followed by the Aptian Stage.See Gradstein ''et al.'' (2004) or the online geowhen database (link below) Stratigraphic definitions The original type locality for the Barremian Stage is in the vicinity of the village of Barrême, Alpes-de-Haute-Provence, France. Henri Coquand defined the stage and named it in 1873. The base of the Barremian is determined by the first appearance of the ammonites '' Spitidiscus hugii'' and ''Spitidiscus vandeckii''. The end of the Barremian is determined by the geomagnetic reversal at the start of the M0r chronozone, which is biologically near the first appearance of the ammonite '' Paradesh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gut (zoology)
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. ''Gastrointestinal'' is an adjective meaning of or pertaining to the stomach and intestines. Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores ( ostia) throughout their body for digestion and a larger dorsal pore ( osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion. The human gast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellimmichthyiformes
The Ellimmichthyiformes, also known as double-armored herrings, are an Extinction, extinct Order (biology), order of Actinopterygii, ray-finned fish known from the Early Cretaceous to the Oligocene. They were the sister group to the extant true herrings, Alosidae, shad and Anchovy, anchovies in the order Clupeiformes, with both orders belonging to the suborder Clupeomorpha. A highly successful group throughout the Cretaceous, they were found worldwide and are known to have inhabited both marine and freshwater habitats. They appear to have been a largely marine group for most of their history, with the first freshwater lineages appearing during the Late Cretaceous. Shortly after the origin of the Ellimmichthyiformes in the Early Cretaceous, the Mediterranean Sea, Mediterranean portion of the Tethys Ocean appears to have been a major center of diversification for them, as the majority of fossils of this group are known from there. Following this, they saw an explosion in diversity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ostariophysan
Ostariophysi is the second-largest superorder of fish. Members of this superorder are called ostariophysians. This diverse group contains 10,758 species, about 28% of known fish species in the world and 68% of freshwater species, and are present on all continents except Antarctica. They have a number of common characteristics such as an alarm substance and a Weberian apparatus. Members of this group include fish important to people for food, sport, the aquarium industry, and research. Taxonomy The superorder is divided into two series, Anotophysi and Otophysi. However, in older literature, Ostariophysi was restricted only to the fish that are currently classified under Otophysi. Otophysi was coined in 1970 by Rosen and Greenwood to separate the traditional Ostariophysians from the added Gonorynchiformes. The superorder is classified below: *Series Anotophysi ** Gonorynchiformes, about 107 species *Series Otophysi (Euostariophysi) ** Cypriniformes (minnows and allies), about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cetomimiformes
The Cetomimoidea or whalefishes are a superfamily of small, deep-sea ray-finned fish. Formerly treated as either their own order (Cetomimiformes) due to their unusual anatomy, more recent studies incorporating genetic data confirm them to be deeply nested within the Beryciformes as a clade within Stephanoberycoidei (which was formerly also treated as its own order). They are thus better treated as their own superfamily, Cetomimoidea. Within this group are five families and approximately 18 genera and 32 species (but see below). Thought to have a circumglobal distribution throughout the tropical and temperate latitudes, whalefishes have been recorded at depths in excess of 3,500 metres. Taxonomy Some recent phylogenetic studies suggest that the whalefishes are paraphyletic with respect to other members of the suborder, with '' Barbourisia'' belonging to the Stephanoberycidae while Rondeletiidae includes '' Hispidoberyx''. Although previously thought to have ancient origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmoniformes
Salmoniformes (, lit. "salmon-shaped") is an Order (biology), order of Actinopterygii, ray-finned fishes native to the temperate and subarctic Northern Hemisphere. It contains two suborders: Salmonoidei (containing only the Salmonidae) and Esocoidei (containing pikes and mudminnows). In addition, potential fossil members of the group, dating back to the Late Cretaceous, are also known from Europe and Africa. Both large-sized members of this order (Salmonidae and Esocidae) are important food and Game fish, sport fish of the Northern Hemisphere. Taxonomy The relationship between Salmon, salmons, Pike (fish), pikes, and Umbridae, mudminnows has long been well-attested based on phylogenetic and morphological studies, and all three groups were long placed in the Salmoniformes. In the early 21st century, pikes and mudminnows were split from the Salmoniformes and placed into their own order, Esociformes. However, as recent studies have reaffirmed their close relationship, more recent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoglossiformes
Osteoglossiformes , meaning "bony tongues" in Ancient Greek, is a relatively primitive order of ray-finned fish that contains two sub-orders, the Osteoglossoidei and the Notopteroidei. All of at least 245 living species inhabit freshwater. They are found in South America, Africa, Australia and southern Asia, having first evolved in Gondwana before that continent broke up. In 2008, several new species of marine osteoglossiforms were described from the Danish Eocene Fur Formation, dramatically increasing the diversity of this group. This implies that the Osteoglossomorpha is not a primary freshwater fish group with the osteoglossiforms having a typical Gondwana distribution. The Gymnarchidae (the only species being '' Gymnarchus niloticus'', the African knifefish) and the Mormyridae are weakly electric fish able to sense their prey using electric fields. The mooneyes (Hiodontidae) are often classified here, but may also be placed in a separate order, Hiodontiformes. Members ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensu Lato
''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular concept, but it also appears in expressions that indicate the convention or context of the usage. Common qualifiers ''Sensu'' is the ablative case of the noun ''sensus'', here meaning "sense". It is often accompanied by an adjective (in the same case). Three such phrases are: * – "in the strict sense", abbreviation ''s.s.'' or ''s.str.''; * – "in the broad sense", abbreviation ''s.l.''; * – "in a relaxed, generous (or 'ample') sense", a similar meaning to ''sensu lato''. Søren Kierkegaard uses the phrase ''sensu eminenti'' to mean "in the pre-eminent r most important or significantsense". When appropriate, comparative and superlative adjectives may also be used to convey the meaning of "more" or "most". Thus ''sensu stricto' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill Raker
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the gill used for gas exchange. Rakers are usually present in two rows, projecting from both the anterior and posterior side of each gill arch. Rakers are widely varied in number, spacing, and form. By preventing food particles from exiting the spaces between the gill arches, they enable the retention of food particles in filter feeders. The structure and spacing of gill rakers in fish determines the size of food particles trapped, and correlates with feeding behavior. Fish with densely spaced, elongated, comb-like gill rakers are efficient at filtering tiny prey, whereas carnivores and omnivores often have more widely spaced gill rakers with secondary projections. Because gill raker characters often vary between closely related taxa, they a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales. Marine plankton include bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. fresh water, Freshwater plankton are similar to marine plankton, but are found in lakes and rivers. Mostly, plankton just drift where currents take them, though some, like jellyfish, swim slowly but not fast enough to generally overcome the influence of currents. Although plankton are usually thought of as inhabiting water, there are also airborne versions that live part of their lives drifting in the at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shoaling And Schooling
In biology, any group of fish that stay together for social reasons are shoaling, and if the group is swimming in the same direction in a coordinated manner, they are schooling. In common usage, the terms are sometimes used rather loosely. About one quarter of fish species shoal all their lives, and about one half shoal for part of their lives. Fish derive many benefits from shoaling behaviour including defence against predators (through better predator detection and by diluting the chance of individual capture), enhanced foraging success, and higher success in finding a mate. It is also likely that fish benefit from shoal membership through increased hydrodynamic efficiency. Fish use many traits to choose shoalmates. Generally they prefer larger shoals, shoalmates of their own species, shoalmates similar in size and appearance to themselves, healthy fish, and kin (when recognized). The oddity effect posits that any shoal member that stands out in appearance will be preferen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
