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Schramidontus
''Schramidontus'' is a genus of crustaceans from the Late Devonian period found in Strud, Belgium, closely related to ''Angustidontus'' and classified as part of the order Angustidontida. It is an important genus because of its position in the eumalacostracan family tree and the insight study of the genus may give of the origin of the Decapoda. The generic name derives from Frederick Schram, who helped the scientific community in the field of the Palaeozoic malacostracans and the suffix ''-idontus'' in relation to the similarities between ''Schramidontus'' and ''Angustidontus''. The specific name is from Labas, a stream that flows near Strud quarry, where the genus was discovered. Description ''Schramidontus'' had a subcylindrical smooth carapace and a triangular telson. It had two pairs of grasping maxillipeds, the second being twice as big as the first, that it could use to bring prey to the maxillae, maxillulae and its large mandibles. This feature was not present in its onl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angustidontus
''Angustidontus'' is a genus of predatory pelagic crustaceans from the Late Devonian and Early Carboniferous periods, classified as part of the subclass Eumalacostraca. Fossils of the genus have been recovered in relative abundance from Canada, Germany, the Czech Republic, Poland, Belarus, Ukraine and large parts of the United States, including Oklahoma, Ohio, Indiana, Kentucky, Montana, Utah, Nevada. The major eumalacostracan lineages had already diverged from each other during the Devonian, but their early evolutionary history remains relatively unknown due to a poor fossil record, making fossils of ''Angustidontus'' and other early eumalacostracans important for scientific study. Historically of uncertain classification, studies on the paleobiology of ''Angustidontus'' have allowed researchers to place it between the eumalacostracan orders Amphionidacea and Decapoda. Description ''Angustidontus'' was a predatory angustidontid crustacean, measuring about 6 centimeters in le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angustidontida
Angustidontidae is an extinct family of eucarid crustaceans and the sole representatives of the order Angustidontida. They were predators ranging in size from about 4 to 9 centimetres in length and lived during the Late Devonian and Early Carboniferous periods. They were some of the earliest Eucarids to develop maxillipeds, modified from the first or second thoracopod The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plu ...s. See also * '' Angustidontus'' References Prehistoric Malacostraca Prehistoric crustacean families {{paleo-crustacean-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angustidontidae
Angustidontidae is an extinct family of eucarid crustaceans and the sole representatives of the order Angustidontida. They were predators ranging in size from about 4 to 9 centimetres in length and lived during the Late Devonian and Early Carboniferous periods. They were some of the earliest Eucarids to develop maxillipeds, modified from the first or second thoracopods. See also * ''Angustidontus ''Angustidontus'' is a genus of predatory pelagic crustaceans from the Late Devonian and Early Carboniferous periods, classified as part of the subclass Eumalacostraca. Fossils of the genus have been recovered in relative abundance from Canada, ...'' References Prehistoric Malacostraca Prehistoric crustacean families {{paleo-crustacean-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eucarida
Eucarida is a superorder of the Malacostraca, a class of the crustacean subphylum, comprising the decapods, krill, '' Amphionides'' and Angustidontida. They are characterised by having the carapace fused to all thoracic segments, and by the possession of stalked eyes. Orders Eucarida is a diverse and abundant group, comprising the following four orders: Euphausiacea The members of the Euphausiacea are commonly called krill and are all marine shrimp-like species whose pleopods (abdominal appendages) function as swimmerets. They swarm and mostly feed on plankton. This group is composed of only 90 species, some of which are the most abundant species on the planet; in fact, it is estimated that the biomass of the Antarctic krill ''Euphausia superba is 500 million tons. Decapoda Decapoda is a group with 15,000 species which have 5 pairs of thoracopods and a well-developed carapace that covers the gills (which are exposed in krill). They include lobsters, crabs, shrimp and praw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Famennian
The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used by the International Commission on Stratigraphy, estimated that it lasted from million years ago to million years ago. It was preceded by the Frasnian stage and followed by the Tournaisian stage. Major events In the seas, a novel major group of ammonoid cephalopods called clymeniids appeared, underwent tremendous diversification and spread worldwide, then just as suddenly went extinct. The beginning of the Famennian is marked by the final stages of a major extinction event, the Kellwasser Event, which is the largest component of the Late Devonian Mass extinction. The end of the Famennian experiences a smaller but still quite severe extinction event, the Hangenberg Event. A brief episode of glaciation, possibly linked to the Hangenber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decapod Anatomy
The decapod (crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various groups these may be reduced or missing. They are, from head to tail: Cephalothorax Head # antennules # antennae #mandibles # first maxillae # second maxillae The head also bears the (usually stalked) compound eyes. The distal portion of a mandible or maxilla which has a sensory function is known as a palp. Thorax / pereon #first maxillipeds #second maxillipeds #third maxillipeds #first pereiopods #second pereiopods #third pereiopods #fourth pereiopods #fifth pereiopods Maxillipeds are appendages modified to function as mouthparts. Particularly in the less advanced decapods, these can be very similar to the pereiopods. Pereiopods are primarily walking legs and are also used for gathering food. They are also the ten legs from which decapods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dactylus
The dactylus is the tip region of the tentacular club of cephalopods and of the leg of some crustaceans (see arthropod leg). In cephalopods, the dactylus is narrow and often characterized by the asymmetrical placement of suckers (i.e., the ventral expansion of the club) and the absence of a dorsal protective membrane. In crustaceans, the dactylus is the seventh and terminal segment of their thoracic appendages. In certain instances the dactylus, together with the propodus, form the claw. The term ''dactylus'' means "finger" in Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor .... References Cephalopod zootomy Crustacean anatomy {{Animal anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia and it is located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Comprising the westernmost peninsulas of Eurasia, it shares the continental landmass of Afro-Eurasia with both Africa and Asia. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south and Asia to the east. Europe is commonly considered to be Boundaries between the continents of Earth#Asia and Europe, separated from Asia by the drainage divide, watershed of the Ural Mountains, the Ural (river), Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea and the waterways of the Turkish Straits. "Europe" (pp. 68–69); "Asia" (pp. 90–91): "A commonly accepted division between Asia and E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euphausiacea
Krill are small crustaceans of the order (biology), order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian language, Norwegian word ', meaning "small Fry (biology), fry of fish", which is also often attributed to species of fish. Krill are considered an important trophic level connection – near the bottom of the food chain. They feed on phytoplankton and (to a lesser extent) zooplankton, yet also are the main source of food for many larger animals. In the Southern Ocean, one species, the Antarctic krill, ''Euphausia superba'', makes up an estimated biomass (ecology), biomass of around 379,000,000 tonnes, making it among the species with the largest total biomass. Over half of this biomass is eaten by whales, Pinniped, seals, penguins, seabirds, squid, and fish each year. Most krill species display large diel vertical migration, daily vertical migrations, thus providing food for predators near the surface at night and in deeper w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracopod
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plural ''coxae''), ''trochanter'', ''femur'' (plural ''femora''), ''tibia'' (plural ''tibiae''), ''tarsus'' (plural ''tarsi''), ''ischium'' (plural ''ischia''), ''metatarsus'', ''carpus'', ''dactylus'' (meaning finger), ''patella'' (plural ''patellae''). Homologies of leg segments between groups are difficult to prove and are the source of much argument. Some authors posit up to eleven segments per leg for the most recent common ancestor of extant arthropods but modern arthropods have eight or fewer. It has been argued that the ancestral leg need not have been so complex, and that other events, such as successive loss of function of a ''Hox''-gene, could result in parallel gains of leg segments. In arthropods, each of the leg segments artic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla (arthropod Mouthpart)
In arthropods, the maxillae (singular maxilla) are paired structures present on the head as mouthparts in members of the clade Mandibulata, used for tasting and manipulating food. Embryologically, the maxillae are derived from the 4th and 5th segment of the head and the maxillary palps; segmented appendages extending from the base of the maxilla represent the former leg of those respective segments. In most cases, two pairs of maxillae are present and in different arthropod groups the two pairs of maxillae have been variously modified. In crustaceans, the first pair are called maxillulae (singular maxillula). Modified coxae at the base of the pedipalps in spiders are also called "maxillae", although they are not homologous with mandibulate maxillae. Myriapoda Millipedes In millipedes, the second maxillae have been lost, reducing the mouthparts to only the first maxillae which have fused together to form a gnathochilarium, acting as a lower lip to the buccal cavity and the man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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