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Amphiaspis
''Amphiaspis argo'' is the type species of the cyathaspidid taxon Amphiaspidida, and of the family Amphiaspididae.Novitskaya, Larisse. Les amphiaspides (Heterostraci) du Devonien de la Siberie. Éditions du Centre national de la recherche scientifique, 1971. Its fossils are restricted to early Emsian-aged marine strata of the Taimyr Peninsula, Early Devonian Siberia. ''A. argo'', as with all other amphiaspidids, is thought to have been a benthic filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ... that lived on top of, or buried just below the surface of the substrate of hypersaline lagoon-bottoms. Anatomy So far, ''A. argos'' is known from at least one, incomplete cephalothoracic armor that is shaped vaguely like a pillow and is, from anterior to posterior, 24 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphiaspididae
Amphiaspididae is a family of extinct amphiaspidid heterostracan agnathans whose fossils are restricted to Lower Devonian marine strata of Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ... near the Taimyr Peninsula. In life, the amphiaspidids of Amphiaspididae are thought to be benthic animals that lived most of their lives mostly buried in the sediment of a series of hypersaline lagoons. Amphiaspids are easily distinguished from other heterostracans in that all of the plates of the cephalothorax armor are fused into a single, muff-like unit, so that the forebody of the living animal would have looked like a potpie with a pair of small, or degenerated eyes, with each flanked by a preorbital opening, and a simple, slit-like mouth. Taxonomy ''Amphiaspis'' ''Amphiaspis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphiaspidida
Amphiaspidida is a taxon of extinct cyathaspidid heterostracan agnathans whose fossils are restricted to Lower Devonian marine strata of Siberia near the Taimyr Peninsula. Some authorities treat it as a suborder of Cyathaspidiformes,Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. while others treat it as an order in its own right as "Amphiaspidiformes."Novitskaya, Larisse. Les amphiaspides (Heterostraci) du Devonien de la Siberie. Éditions du Centre national de la recherche scientifique, 1971. In life, they are thought to be benthic animals that lived most of their lives mostly buried in the sediment of a series of hypersaline lagoons. Amphiaspids are easily distinguished from other heterostracans in that all of the plates of the cephalothorax armor are fused into a single, muff-like unit, so that the forebody of the living animal would have looked like a potpie or a hot waterbottle with a pair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterostraci Genera
Heterostraci (Ancient Greek, ἕτερος+ὄστρακον "those itha different shell" i is pl. of -us is an extinct subclass of pteraspidomorph jawless vertebrate that lived primarily in marine and estuary environments. Heterostraci existed from the mid-Ordovician to the conclusion of the Devonian. Description and anatomy The Heterostracans differed from other Paleozoic agnathan taxa both in the arrangement and histology of their scales. Most heterostracans had two plates which form a large dorsal shield and a large ventral shield, and had series of scales arranged in various patterns on the sides of their bodies, the exact pattern differing from one group to another. In a few primitive forms, such as '' Lepidaspis'', the dorsal and ventral shields are composed of a mosaic of tiny scales. In most other known forms, though, these tiny scales have fused together to form the shield-plates. The scales of heterostracans are histologically distinct from other vertebrate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emsian
The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the Ems river in Germany. The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological Reserve of Uzbekistan, above the contact with the Madmon Formation. In North America the Emsian Stage is represented by Sawkill or Sawkillian time. Biological events During this period, earliest known agoniatitid ammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which a new ammonoid order Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after the end of Early Devonian, before 391.9 mya). Later agoniatitid ammonoids would die out in the Taghanic event in the upper middle Givetian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Feeder
Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish (including some sharks). Some birds, such as flamingos and certain species of duck, are also filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms. Fish Most forage fish are filter feeders. For example, the Atlantic menhaden, a type of herring, lives on plankton caught in midwater. Adult menhaden can filter up to four gallons of water a minute and play an important role in clarifying ocean water. They are also a natural check to the deadly red tide. Extensive article on the role of menhaden in the ecosystem and possible resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils Of Russia
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fauna Of Siberia
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] |
Early Devonian Fish
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Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early Branch, a stream in Missouri * Early County, Georgia Other uses * ''Early'' (Scritti Politti album), 2005 * ''Early'' (A Certain Ratio album), 2002 * Early (name) * Early effect, an effect in transistor physics * Early Records, a record label * the early part of the morning See also * Earley (other) Earley is a town in England. Earley may also refer to: * Earley (surname), a list of people with the surname Earley * Earley (given name), a variant of the given name Earlene * Earley Lake, a lake in Minnesota *Earley parser, an algorithm *Earley ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian Jawless Fish
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyathaspidiformes Genera
Cyathaspidiformes is an extinct order of heterostracan vertebrates known from extensive fossil remains primarily from Silurian to Early Devonian strata of Europe, and North America, and from Early Devonian marine strata of Siberia. Anatomy Like their descendants, the pteraspidids, all cyathaspidiform heterostracans had the cephalothorax enclosed in armor, formed from several plates, including dorsal, ventral, a dorsal spine derived from a scale, and a large, scale-covered tail. Thus, the living animals would have resembled tadpoles encased in massive armor. The majority of taxa have the rostral and pineal plates fused or merged with the dorsal plate, and in the amphiaspidids, all the plates of the cephalothorax were fused together into a single "muff-like" unit. Unlike the pteraspidids, all cyathaspidiforms are thought to be almost uniformly benthic in lifestyle, though only the amphiaspids and the ctenaspids are thought to be burrowers. Taxonomy The taxonomy of Cyathaspidifo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalothorax
The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cephalothorax'' and ''abdomen'' in some groups.) The word ''cephalothorax'' is derived from the Greek words for head (, ') and thorax (, '). This fusion of the head and thorax is seen in chelicerates and crustaceans; in other groups, such as the Hexapoda (including insects), the head remains free of the thorax. In horseshoe crabs and many crustaceans, a hard shell called the carapace covers the cephalothorax. Arachnid anatomy Fovea The fovea is the centre of the cephalothorax and is located behind the head (only in spiders).Dalton, Steve (2008). ''Spiders; The Ultimate Predators''. A & C Black, London. P.p. 19. . It is often important in identification. It can be transverse or procurved Smith, A. M. (1990c). Baboon spiders: Tarantulas of Afri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypersaline
A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing that of ocean water (3.5%, i.e. ). Specific microbial species can thrive in high-salinity environments that are inhospitable to most lifeforms, including some that are thought to contribute to the colour of pink lakes. Some of these species enter a dormant state when desiccated, and some species are thought to survive for over 250 million years. The water of hypersaline lakes has great buoyancy due to its high salt content. Hypersaline lakes are found on every continent, especially in arid or semi-arid regions. In the Arctic, the Canadian Devon Ice Cap contains two subglacial lakes that are hypersaline. In Antarctica, there are larger hypersaline water bodies, lakes in the McMurdo Dry Valleys such as Lake Vanda with salinity of over 35% (i.e. 10 times as salty as ocean water). The most saline water body in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
