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Stylonuroid
Stylonuroidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina. Stylonuroidea, which lived from the Early Silurian to the Late Devonian, were characterized by their last pair of prosomal (head) appendages, which were developed as walking legs, or less commonly developed as swimming legs with paddles formed by the expansion of the two or three penultimate joints. 1955. Merostomata. ''Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata'', P36. as Stylonuracea Description Stylonuroids are designated as stylonurines with flattened or truncated posterior metastomata margins. Of the four stylonurine superfamilies, the Stylonuroidea is the most poorly known. Whilst the topology of most stylonurine clades fit well with the stratigraphic record, Stylonuroidea is an exception in that the earliest record of the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stylonurina
Stylonurina is one of two suborders of eurypterids, a group of extinct arthropods commonly known as "sea scorpions". Members of the suborder are collectively and informally known as "stylonurine eurypterids" or "stylonurines". They are known from deposits primarily in Europe and North America, but also in Siberia. Compared to the other suborder, Eurypterina, the stylonurines were comparatively rare and retained their posterior prosomal appendages for walking. Despite their rarity, the stylonurines have the longest temporal range of the two suborders. The suborder contains some of the oldest known eurypterids, such as ''Brachyopterus'', from the Middle Ordovician as well as the youngest known eurypterids, from the Late Permian. They remained rare throughout the Ordovician and Silurian, though the radiation of the mycteropoids (a group of large sweep-feeding forms) in the Late Devonian and Carboniferous is the last major radiation of the eurypterids before their extinction in the Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stylonurella
''Stylonurella'' is a genus of prehistoric eurypterid. It is classified within the Parastylonuridae family and contains three species, ''S. arnoldi'' and ''S. beecheri'' from the Devonian of Pennsylvania, United States and ''S. spinipes'' from the Silurian of Kip Burn, Scotland.Dunlop, J. A., Penney, D. & Jekel, D. 2015. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch, version 16.0 http://www.wsc.nmbe.ch/resources/fossils/Fossils16.0.pdf (PDF). Description ''Stylonurella'' was a small stylonuroid, possessing a subquadrate prosoma with approximately the same length as width. The midsection was slightly constricted and the eyes were parallel and anteriorly located in the anterior half of the carapace. The metastoma and first two appendages are unknown, the third and fourth prosomal legs are very short and the last two walking legs are very long. The metasoma is very narrow. A revision of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parastylonuridae
The Parastylonuridae are a family of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". The family is one of two families contained in the superfamily Stylonuroidea (along with Stylonuridae), which in turn is one of four superfamilies classified as part of the suborder Stylonurina. Description Parastylonurids are stylonuroids with a posterior second order opisthosomal differentiation and with spiniferous appendages II-IV akin to the genus '' Hughmilleria'' and non-spiniferous appendages V-VI akin to the genus '' Parastylonurus'' or '' Pagea''. Unlike the close relatives in the Stylonuridae, there are no adaptations towards sweep-feeding within the Parastylonuridae. They retain primitive ''Hughmilleria''-like prosomal appendages II-IV unsuited for such a lifestyle, and they were likely scavengers instead of sweep-feeders. Systematics and genera The Stylonuridae is classified within the superfamily Stylonuroidea within the Stylonur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stylonuridae
Stylonuridae is a family of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". The family is one of two families contained in the superfamily Stylonuroidea (along with Parastylonuridae), which in turn is one of four superfamilies classified as part of the suborder Stylonurina. Stylonuridae, which lived from Early Silurian to the Late Devonian, were small to very large forms with scales developing into tubercules and knobs. The prosoma (head) exhibited variable shape, with arcuate compound eyes located subcentrally, or anteriorly. Their abdomens were slender. Their walking legs were long and powerful, sometimes characterized by spines. Most genera did not have swimming legs. 1955. Merostomata. ''Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata'', P: 36. Description Stylonurids are stylonuroids with undifferentiated opisthosoma with appendages II-IV being spiniferous akin to the genus '' Ctenopterus'', whilst append ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soligorskopterus
''Soligorskopterus'' is a genus of eurypterid, a group of extinct aquatic arthropods. Fossils of ''Soligorskopterus'' have been discovered in deposits from the Late Devonian. The genus contains two species: ''S. tchepeliensis'', the type species, from the Middle Famennian stage of Belarus, and ''S. shpinevi'', from the Lower Frasnian stage of Russia. Its name derives from Soligorsk, the closest city from the fossil site of the type species, and the Greek word πτερόν (''pteron''), which means wing. See also * List of eurypterid genera * Timeline of eurypterid research This timeline of eurypterid research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of eurypterids, a group of extinct aquatic arthropods closely related to modern arac ... References Devonian eurypterids Eurypterids of Europe Frasnian life Famennian life Fossils of Russia Fossil taxa described in 2018 Stylonuroidea [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hibbertopteroidea
Mycteropoidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina. Mycteropoids have been recovered from Europe, Russia, South America and South Africa. Mycteropoid specimens are often fragmentary, making it difficult to establish relationships between the included taxa. Only two mycteropoid taxa are known from reasonable complete remains, ''Hibbertopterus scouleri'' and ''H. wittebergensis''. Mycteropoids were large bizarre Eurypterids found from the Early Silurian to the end of the Permian period. They were sweep feeders, inhabiting freshwater swamps and rivers, feeding by raking through the soft sediment with blades on their anterior appendages to capture small invertebrates. Their morphology was so unusual that they have been thought to be an order separate to Eurypterida. Recent work however confirms them to be derived members of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parastylonurus
''Parastylonurus'' is a genus of prehistoric eurypterid. It is classified within the Parastylonuridae family and contains three species, ''P. hendersoni'' and ''P. ornatus'' from the Silurian of Scotland and ''P. sigmoidalis'' from the Silurian of England.Dunlop, J. A., Penney, D. & Jekel, D. 2015. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch, version 16.0 http://www.wsc.nmbe.ch/resources/fossils/Fossils16.0.pdf (PDF). Description ''Parastylonurus'' was a stylonuroid of small to medium size with a rounded prosoma wider than it was long. The eyes were located on the anterior half of the carapace and the metasoma was very long. The first three walking legs were very short with single opposable spines on every joint. The last two walking legs were very long, reaching to the last tergite. The opisthosoma was narrow and undifferentiated and the telson was spike-like. Classification ''Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhuddanian
In the geologic timescale, the Rhuddanian is the first age of the Silurian Period and of the Llandovery Epoch. The Silurian is in the Paleozoic Era of the Phanerozoic Eon. The Rhuddanian Age began 443.8 ± 1.5 Ma and ended 440.8 ± 1.2 Ma (million years ago). It succeeds the Himantian Age (the last age of the Ordovician Period) and precedes the Aeronian Age. GSSP The GSSP for the Silurian is located in a section at Dob's Linn, Scotland, in an artificial excavation created just north of the Linn Branch Stream. Two lithological units ( formations) occur near the boundary. The lower is the Hartfell Shale ( thick), consisting chiefly of pale gray mudstone with subordinate black shales and several interbedded meta-bentonites. Above this is the thick Birkhill Shale, which consist predominantly of black graptolitic shale with subordinate gray mudstones and meta-bentonites. See also * Ordovician-Silurian extinction events * Early Palaeozoic Icehouse The Andean-Saharan glaciatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laurieipterus
''Laurieipterus'' is a genus of a eurypterid classified as part of the family Stylonuridae. It contains one species, ''L. elegans'' from the Early Silurian of Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ....Dunlop, J. A., Penney, D. & Jekel, D. 2015. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch, version 16.0 http://www.wsc.nmbe.ch/resources/fossils/Fossils16.0.pdf (PDF). References Silurian arthropods of Europe Silurian eurypterids Stylonuroidea Eurypterids of Europe {{eurypterid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stylonuroidea
Stylonuroidea is an extinct superfamily of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". It is one of four superfamilies classified as part of the suborder Stylonurina. Stylonuroidea, which lived from the Early Silurian to the Late Devonian, were characterized by their last pair of prosomal (head) appendages, which were developed as walking legs, or less commonly developed as swimming legs with paddles formed by the expansion of the two or three penultimate joints. 1955. Merostomata. ''Treatise on Invertebrate Paleontology, Part P Arthropoda 2, Chelicerata'', P36. as Stylonuracea Description Stylonuroids are designated as stylonurines with flattened or truncated posterior metastomata margins. Of the four stylonurine superfamilies, the Stylonuroidea is the most poorly known. Whilst the topology of most stylonurine clades fit well with the stratigraphic record, Stylonuroidea is an exception in that the earliest record of the most der ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyly
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic group (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term was coined by Willi Hennig to apply to well-known taxa like Reptilia ( reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor, including all extant reptiles as well as the extinct synapsids, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pagea
''Pagea'' is a genus of prehistoric eurypterid classified as part of the family Stylonuridae. It contains three species, all from the Devonian (Lochkovian to Pragian); ''P. plotnicki'' from Nunavut, Canada and ''P. sturrocki'' and ''P. symondsii'' from the Old Red Sandstone of the United Kingdom.Dunlop, J. A., Penney, D. & Jekel, D. 2015. A summary list of fossil spiders and their relatives. In World Spider Catalog. Natural History Museum Bern, online at http://wsc.nmbe.ch, version 16.0 http://www.wsc.nmbe.ch/resources/fossils/Fossils16.0.pdf (PDF). The genus is named in honor of David Page, an early worker on the fauna of the Old Red Sandstone and describer of the first Stylonurine eurypterid. Description ''Pagea'' was a large stylonurid eurypterid. The third and fourth prosomal appendages bore double rows of flat spines. The prosoma was subrectangularly shaped, with the eyes located on the anterior half. The metastoma was narrow in relation to the width of the prosoma, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
