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Boreaspis
''Boreaspis'' (meaning " Boreas's Shield") is an extinct genus of osteostracan agnathan vertebrate that lived in the Devonian period. Fourteen different species of ''Boreaspis'' have been found in sandstone of the lagoons and estuaries of Devonian Spitsbergen; however, some of these likely do not belong to the genus. The species ''B. robusta'' and ''B. costata'' have been reassigned to '' Spatulaspis''; and ''B. circinus'', ''B. curtirostris'', and ''B. gracilis'' now belong to '' Dicranaspis''. Species of ''Boreaspis'' were very small, with head shields about long. All species possessed a long spathe-like rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ... derived from the anterior-most end of the head shield, which would have enhanced the fish's hydrodynamics and was pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteostraci
The class Osteostraci (meaning "bony shells") is an extinct taxon of bony-armored jawless fish, termed " ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian. Anatomically speaking, the osteostracans, especially the Devonian species, were among the most advanced of all known agnathans. This is due to the development of paired fins, and their complicated cranial anatomy. The osteostracans were more similar to lampreys than to jawed vertebrates in possessing two pairs of semicircular canals in the inner ear, as opposed to the three pairs found in the inner ears of jawed vertebrates. They are thought to be the sister-group to pituriaspids, and together, these two taxa of jawless vertebrates are the sister-group of gnathostomes. Several synapomorphies support this hypothesis, such as the presence of: sclerotic ossicles, paired pectoral fins, a dermal skeleton with three layers (a basal layer of isopedin, a middle layer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteostraci Genera
The class Osteostraci (meaning "bony shells") is an extinct taxon of bony-armored jawless fish, termed "ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian. Anatomically speaking, the osteostracans, especially the Devonian species, were among the most advanced of all known agnathans. This is due to the development of paired fins, and their complicated cranial anatomy. The osteostracans were more similar to lampreys than to jawed vertebrates in possessing two pairs of semicircular canals in the inner ear, as opposed to the three pairs found in the inner ears of jawed vertebrates. They are thought to be the sister-group to pituriaspids, and together, these two taxa of jawless vertebrates are the sister-group of gnathostomes. Several synapomorphies support this hypothesis, such as the presence of: sclerotic ossicles, paired pectoral fins, a dermal skeleton with three layers (a basal layer of isopedin, a middle layer o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erik Stensiö
Prof Erik Helge Osvald Stensiö HFRSE (2 October 1891 – 11 January 1984), né Andersson, was an influential Swedish paleozoologist and founder of the so-called "Stockholm School" of vertebrate paleontology. He later took his new surname, Stensiö, from his place of origin and is occasionally referred to with both names (as Erik Andersson Stensiö, Erik A. Stensiö or Erik A:son Stensiö) Life Erik Helge Oswald Andersson, as his original name was, was born in the village of Stensjö by in Döderhult parish in Kalmar County, the son of Johan Fredrik Andersson (d.1907), a farmer, and his wife, Otilia Maria Erlandson (d.1940). He was educated at Linköping Gymnasium. He then studied science at the University of Uppsala, graduating BSc in 1912. He received his Ph.D. and a docentship in paleontology from Uppsala University in 1921 and became professor and keeper at the Zoopaleontological (later called the Paleozoological) department of the Swedish Museum of Natural History ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnatha
Agnatha (; ) or jawless fish is a paraphyletic infraphylum of animals in the subphylum Vertebrata of the phylum Chordata, characterized by the lack of jaws. The group consists of both extant taxon, living (Cyclostomi, cyclostomes such as hagfishes and lampreys) and Extinction, extinct clades (e.g. conodonts and Cephalaspidomorphi, cephalaspidomorphs, among others). They are sister taxon, sister to vertebrates with jaws known as gnathostomes, who evolution, evolved from jawless ancestors during the early Silurian by developing folding joint, articulations in the first pairs of gill arches. Sequencing, Molecular data, both from rRNA and from mtDNA as well as Embryology, embryological data, strongly supports the hypothesis that both groups of living agnathans, hagfishes and lampreys, are more closely related to each other than to Gnathostomata, jawed fish, forming the Class (biology), superclass Cyclostomi. The oldest fossil agnathans appeared in the Cambrian. Living jawless fish c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pragian
The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 410.8 ± 2.8 million years ago to 407.6 ± 2.8 million years ago. It was preceded by the Lochkovian Stage and followed by the Emsian Stage. The most important Lagerstätte of the Pragian is Rhynie chert in Scotland. It is named after the city of Prague Prague ( ; ) is the capital and List of cities and towns in the Czech Republic, largest city of the Czech Republic and the historical capital of Bohemia. Prague, located on the Vltava River, has a population of about 1.4 million, while its P .... The GSSP is located within the Prague Formation at Velká Chuchle, Prague. In North America the Pragian Stage is represented by Siegenian or Deerparkian time. Pragian life The first ammonoids (order Agoniatitida) appeared in later parts of this stage (at the lower boundary of the Zlichovian stage as it was known in Siberian representations). They were descended from bactritoid nautiloi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') and ''atoll lagoons''. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as Estuary, estuaries. Lagoons are common coastal features around many parts of the world. Definition and terminology Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed shoal, reef, coral reef, or similar feature. Some authorities include fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of salinity. The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Devonian Fish Of Europe
Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican dancehall and reggae deejay Earlando Arrington Neil (1957–1994) * Early James, stage name of American singer-songwriter Fredrick Mullis Jr. (born 1993) * ''Early'' (Scritti Politti album), 2005 * ''Early'' (A Certain Ratio album), 2002 * Early Records, a record label Other uses * Early (name), a list of people and fictional characters with the given name or surname * Early effect, an effect in transistor physics * Early, a synonym for ''hotter'' in stellar classification See also * * The Earlies, a 21st century band * Earley (other) * Earlie Earlie is a masculine given name which may refer to: * Earlie Fires (born 1947), American jockey * Earlie Thomas (1945–2022), American National Football League player * Earlie End ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rostrum (anatomy)
Rostrum (from Latin ', meaning '':wikt:beak, beak'') is a term used in anatomy for several kinds of hard, beak-like structures projecting out from the head or mouth of an animal. Despite some visual similarity, many of these are Phylogenetics, phylogenetically unrelated structures in widely varying species. Invertebrates * In spiders, the rostrum is a part of the mouth of which it borders the opening in front. Homologous of an upper lip, this outgrowth is especially characterised by the presence of a pocket-shaped secreting organ, the rostral gland, only accessible by the sole means of histology and electron microscopy (external link "archentoflor"). * In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes. It is generally a rigid structure, but can be connected by a hinged joint, as seen in Leptostraca. * Among insects, the rostrum is the name for the piercing insect mouthparts, mouthparts of the order Hemiptera as well as those of the snow s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spathe
In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves in size, color, shape or texture. They also look different from the parts of the flower, such as the petals or sepals. A plant having bracts is referred to as bracteate or bracteolate, while one that lacks them is referred to as ebracteate or ebracteolate. Variants Some bracts are brightly coloured which aid in the attraction of pollinators, either together with the perianth or instead of it. Examples of this type of bract include those of '' Euphorbia pulcherrima'' (poinsettia) and ''Bougainvillea'': both of these have large colourful bracts surrounding much smaller, less colourful flowers. In grasses, each floret (flower) is enclosed in a pair of papery bracts, called the lemma (lower bract) and palea (upper bract), while each spikelet (group of florets) has a further pair of bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicranaspis (osteostracan)
''Proteides'' is a Neotropical genus of spread-winged skipper butterflies in the family Hesperiidae. Species The following two species are recognised in the genus ''Proteides'' *'' Proteides maysi'' (Lucas, 1857) Cuba *'' Proteides mercurius'' (Fabricius, 1787) South America, Arizona **''P. m. mercurius'' French Guiana, Suriname **''P. m. sanantonio '' (Lucas, 1857) Cuba **''P. m. angasi '' Godman & Salvin, 1884 Dominica **''P. m. pedro'' (Dewitz, 1877) Puerto Rico **''P. m. jamaicensis '' Skinner, 1920 Jamaica **''P. m. sanchesi'' Bell & Comstock, 1948 Haiti **''P. m. vincenti'' Bell & Comstock, 1948 Saint Vincent **''P. m. grenadensis '' Enrico & Pinchon, 1969 Grenada Former species *''Proteides modius'' Mabille, 1889 - transferred to ''Thoon modius'' (Mabille, 1889) References ''Proteides''- Natural History Museum Lepidoptera genus database External links images representing ''Proteides''at Consortium for the Barcode of Life The Consortium for the Barcode of Life (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spitsbergen
Spitsbergen (; formerly known as West Spitsbergen; Norwegian language, Norwegian: ''Vest Spitsbergen'' or ''Vestspitsbergen'' , also sometimes spelled Spitzbergen) is the largest and the only permanently populated island of the Svalbard archipelago in northern Norway in the Arctic Ocean. Constituting the westernmost bulk of the archipelago, it borders the Arctic Ocean, the Norwegian Sea and the Greenland Sea. Spitsbergen covers an area of , making it the largest island in Norway and the List of islands by area, 36th largest in the world. The administrative centre is Longyearbyen. Other settlements, in addition to research outposts, are the mining community of Barentsburg, the research community of Ny-Ålesund, and the mining outpost of Sveagruva. Spitsbergen was covered in of ice in 1999, which was approximately 58.5% of the island's total area. The island was first used as a whaling base in the 17th and 18th centuries, after which it was abandoned. Coal mining started at the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
