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Cyathaspidida
Cyathaspidida is a taxon of extinct cyathaspidiform heterostracan agnathans whose fossils are found in Silurian to Lower Devonian marine strata of Europe and North America.Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. In life, they are thought to be benthic animals that lived most of their lives either mostly buried in or resting directly on top of the substrate. Taxonomy The cyathaspidids of Cyathaspidida were tadpole-like animals with drum-shaped, cigar-shaped or wedge-shaped cephalothoraxes, and were anatomically similar to several other heterostracan groups. However, with some groups, such as the traquairaspids, cardiopeltids, and corvaspidids, this similarity appears to be superficial. With other groups, namely the tolypelepidids, the similarity suggests a close relationship. The type genus of the tolypelepidids, '' Tolypelepis'', in particular, was determined to be the sister-taxon of Cya ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyathaspidiformes
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] |
Cyathaspidae
Cyathaspididae is an extinct family in the heterostracan order Cyathaspidiformes.The Classification and Evolution of the Heterostraci. L. Beverly Tarlo, Acta Palaeontologica Polonica, 1962 Cyathaspididae contains most of the genera originally contained within Cyathaspididae, as well as those genera contained within Irregularaspididae, and Poraspididae. In addition to the type genus, †''Cyathaspis'', Cyathaspididae contains the following genera: †'' Americaspis'', †'' Archegonaspis'', †'' Capitaspis'', †'' Dikenaspis'', †'' Dinaspidella'', †'' Homaspidella'', †'' Irregulareaspis'', †'' Nahanniaspis'', †'' Pionaspis'', †''Poraspis ''Poraspis'' is an extinct genus of heterostracan. Fossils are found in Late Silurian and Early Devonian marine strata of Norway, Canada and the United States The United States of America (U.S.A. or USA), commonly known as the United ...'', †'' Ptomaspis'', †'' Seretaspis'', †'' Steinaspis'', †'' Torpedaspis'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anglaspis
''Anglaspis'' is an extinct genus of cyathaspidiform heterostracan agnathan. Fossils are found in marine strata of Europe, from the late Silurian period until the genus' extinction during the Early Devonian. As with other cyathaspidiforms, individuals of ''Anglaspis'' had dorsal and ventral plates covering the forebody, gill pouches, and nasal openings that lay on the roof of the oral cavity. Late Silurian species of ''Anglaspis'' are found in marine strata of Wales and England, while most of the Early Devonian species are found in the Devonian-aged strata of Spitsbergen island, in Svalbard, Norway. Taxonomy ''Anglaspis'' was, at various times, placed in the families Cyathaspididae, Poraspididae, and in its own family, Anglaspididae. Currently, it is placed in Ariaspidae with ''Ariaspis ''Ariaspis'' is an extinct genus of cyathaspidiform heterostracan agnathan. Fossils are found in marine strata of Canada and Europe from the late Silurian period until its extinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariaspidae
Ariaspidae is a family of extinct cyathaspidiform heterostracan agnathans in the suborder Cyathaspidida. Family Ariaspidae contains ''Ariaspis'', and its sister-taxa originally contained within Anglaspididae/Anglaspidinae, including ''Anglaspis ''Anglaspis'' is an extinct genus of cyathaspidiform heterostracan agnathan. Fossils are found in marine strata of Europe, from the late Silurian period until the genus' extinction during the Early Devonian. As with other cyathaspidiforms, i ...'', '' Listraspis'', '' Liliaspis'', and '' Paraliliaspis''.Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. References * Phylogenetic patterns in the heterostracan families Cyathaspidae, Ariaspidae and Ctenaspidae. Lundgren Mette and Blom Henning, The 2nd Wiman meeting : Carl Wiman's Legacy: 100 years of Swedish Palaeontology : Uppsala 17–18 November 2011, 16-17 p. Cyathaspidida Prehistoric jawless fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ctenaspidae
Ctenaspidae is a family of extinct cyathaspidiform heterostracan agnathans in the suborder Cyathaspidida Cyathaspidida is a taxon of extinct cyathaspidiform heterostracan agnathans whose fossils are found in Silurian to Lower Devonian marine strata of Europe and North America.Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cya .... If Amphiaspidida can be ignored as a daughter-taxon, the family Ctenaspidae contains '' Ctenaspis'' and its various sister-taxa originally contained within both Ctenaspididae and Ctenaspididae, including '' Allocryptaspis'', '' Alainaspis'', '' Zaphoctenaspis'', '' Arctictenaspis'', and '' Boothiaspis'', which was first described as a "Canadian amphiaspid."Lundgren, Mette, and Henning Blom. "Phylogenetic relationships of the cyathaspidids (Heterostraci)." GFF 135.1 (2013): 74-84. References Cyathaspidida Prehistoric jawless fish families {{Devonian-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariaspis
''Ariaspis'' is an extinct genus of cyathaspidiform heterostracan agnathan. Fossils are found in marine strata of Canada and Europe from the late Silurian period until its extinction during the Early Devonian 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, whe .... A new species, ''A. arctata'', was described by David K. Elliott and Sandra Swift in 2010. References Cyathaspidiformes genera Devonian jawless fish Silurian jawless fish Silurian first appearances Early Devonian genus extinctions Cyathaspidida Silurian fish of North America Silurian fish of Europe Paleozoic life of the Northwest Territories {{Pteraspidomorphi-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poraspis
''Poraspis'' is an extinct genus of heterostracan. Fossils are found in Late Silurian and Early Devonian marine strata of Norway, Canada and the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori .... References Cyathaspidida Silurian first appearances Devonian extinctions Fossil taxa described in 1930 Paleozoic jawless fish Paleozoic fish of North America Cyathaspidiformes genera {{Devonian-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyathaspis
''Cyathaspis'' is the type genus of the heterostracan order Cyathaspidiformes. Fossils are found in late Silurian strata in the Cunningham Creek Formation, New Brunswick, Canada and Europe, especially in the Downton Castle Sandstone of Great Britain and Gotland, Sweden. The living animal would have looked superficially like a tadpole, albeit covered in bony plates composed of the tissue aspidine, which is unique to heterostracan armor. ''Cyathaspis ludensis'' is the earliest British vertebrate fossil. It was found in rocks at Leintwardine Leintwardine ( ) is a small to mid-size village and civil parish in north Herefordshire, England, close to the border with Shropshire. History Roman A popular misconception is that the Romans called the village ''Branogenium''. Branogenium in f ... in Herefordshire, a noted fossil locality. References Cyathaspidida Cyathaspidiformes genera Wenlock first appearances Ludlow life Silurian extinctions Silurian jawless fish Silur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capitaspis
''Capitaspis'' is an extinct genus of cyathaspidine cyathaspidid heterostracan jawless vertebrate known from the Late Silurian Somerset Island Formation ( Pridolian epoch) of the Northwest Territories, Canada. It contains a single species In biology, a species is the basic unit of 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 s ..., ''Capitaspis giblingi''. It is most closely related to '' Pionaspis''. References Cyathaspidiformes genera Monotypic fish genera Fossil taxa described in 2013 Cyathaspidida Silurian jawless fish Fossils of Canada Paleontology in the Northwest Territories {{silurian-animal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterostraci
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] |
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] |
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