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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] |
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] |
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] |
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] |
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] |
Wenlock First Appearances
Wenlock may refer to: Places United Kingdom * Little Wenlock, a village in Shropshire * Much Wenlock, a town in Shropshire ** (Much) Wenlock (UK Parliament constituency) ** Wenlock Priory, a 7th/12th-century monastery * Wenlock Basin, a canal basin in London * Wenlock Edge, a limestone escarpment near Much Wenlock Elsewhere * Wenlock, Queensland, Australia * Wenlock, Essex County, Vermont, USA * Wenlock River, Queensland, Australia People * Baron Wenlock, a title created three times in the Peerage of England and of the United Kingdom ** John Wenlock, 1st Baron Wenlock ** Robert Lawley, 1st Baron Wenlock (1768–1834) ** Paul Thompson, 1st Baron Wenlock (1784–1842) ** Beilby Lawley, 2nd Baron Wenlock (1818–1880) ** Beilby Lawley, 3rd Baron Wenlock (1849–1912) ** Arthur Lawley, 6th Baron Wenlock (1860–1932) * Milburga of Wenlock (died 715), Benedictine abbess of Wenlock Abbey Geology * Wenlock epoch, the second series of the Silurian * Wenlock Group or Wenlockian, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tadpole
A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found in adult amphibians such as a lateral line, gills and swimming tails. As they undergo metamorphosis, they start to develop functional lungs for breathing air, and the diet of tadpoles changes drastically. A few amphibians, such as some members of the frog family Brevicipitidae, undergo direct development i.e., they do not undergo a free-living larval stage as tadpoles instead emerging from eggs as fully formed "froglet" miniatures of the adult morphology. Some other species hatch into tadpoles underneath the skin of the female adult or are kept in a pouch until after metamorphosis. Having no hard skeletons, it might be expected that tadpole fossils would not exist. However, traces of biofilms have been preserved and fossil tadpoles have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 fact refers to a Roman fort roughly south of the village. The Roman name for Leintwardine was actually ''Bravonium''. The High Street in Leintwardine is on the same line as the Roman road known (to the English) as Watling Street. (The modern-day street in the village named Watling Street runs to the east of the original Watling Street, roughly on the alignment of the eastern edge of the Roman settlement.) The name Bravonium, as it appears in the Antonine Itinerary (Iter XII), is derived from the Romano-British word for quern. This suggests that there was either a hill or rock formation here that looked like a quern, or that there were quern quarries nearby. In the Upper Silurian series, the Leintwardine beds outcrop in the area and these c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian Extinctions
The Silurian ( ) is a period (geology), geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago (annum, Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozoic Era (geology), Era. As with other geologic periods, the Rock (geology), rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods (myriapods, arachnids and Hexapoda, hexapods) became fully t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludlow Life
Ludlow () is a market town in Shropshire, England. The town is significant in the history of the Welsh Marches and in relation to Wales. It is located south of Shrewsbury and north of Hereford, on the A49 road which bypasses the town. The town is near the confluence of the rivers Corve and Teme. The oldest part is the medieval walled town, founded in the late 11th century after the Norman conquest of England. It is centred on a small hill which lies on the eastern bank of a bend of the River Teme. Situated on this hill are Ludlow Castle and the parish church, St Laurence's, the largest in the county. From there the streets slope downward to the rivers Corve and Teme, to the north and south respectively. The town is in a sheltered spot beneath Mortimer Forest and the Clee Hills, which are clearly visible from the town. Ludlow has nearly 500 listed buildings, including examples of medieval and Tudor-style half-timbered buildings. The town was described by Sir John Betjeman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
