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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] |
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] |
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] |
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] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland, and many smaller islands within the British Isles. Northern Ireland shares a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. The total area of the United Kingdom is , with an estimated 2020 population of more than 67 million people. The United Kingdom has evolved from a series of annexations, unions and separations of constituent countries over several hundred years. The Treaty of Union between the Kingdom of England (which included Wales, annexed in 1542) and the Kingdom of Scotland in 170 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Eurypterids
This list of eurypterid genera is a comprehensive listing of all genera that have ever been included in the order Eurypterida, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful ('' nomen dubium''), or were not formally published ('' nomen nudum''), as well as junior synonyms of more established names and genera that are no longer considered eurypterids. The list currently includes 115 names out of which 74 are considered valid eurypterid genera. There are approximately 250 species of eurypterids recognized as valid. Naming conventions and terminology There is no "official" or "canonical" list of eurypterid genera. The closest thing is found contained in the regularly updated ''Summary list'' ''of fossil spiders and their relatives'' in the World Spider Catalog. The vast majority of the content of the list below, including the valid genera, preoccupied names, junior synonyms, taxonomical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian Eurypterids
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] |
Telson
The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on account of not arising in the embryo from teloblast areas as other segments. It never carries any appendages, but a forked "tail" called the caudal furca may be present. The shape and composition of the telson differs between arthropod groups. Crustaceans In lobsters, shrimp and other decapods, the telson, along with the uropods, forms the tail fan. This is used as a paddle in the caridoid escape reaction ("lobstering"), whereby an alarmed animal rapidly flexes its tail, causing it to dart backwards. Krill can reach speeds of over 60 cm per second by this means. The trigger time to optical stimulus is, in spite of the low temperatures, only 55 milliseconds. In the Isopoda and Tanaidacea (superorder Peracarida), the last abdominal b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prosoma
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 Afr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypterid
Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the Order (biology), order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 Myr, million years ago. The group is likely to have appeared first either during the Early Ordovician or Late Cambrian period. With approximately 250 species, the Eurypterida is the most diverse Paleozoic Chelicerata, chelicerate order. Following their appearance during the Ordovician, eurypterids became major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described. The Silurian genus ''Eurypterus'' accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event. They declined in numbers and diversity until becoming extinct during the Permian–Tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Page (geologist)
David Page FRSE FGS LLD (1814–1879) was a 19th-century Scottish geologist and scientific author. He was President of the Edinburgh Geological Society. Page was born on 24 August 1814 in Lochgelly, Fifeshire, where his father was a mason and builder. After being educated locally he was sent, at age 14, to the University of St Andrews, to be study divinity. However, he never joined the ministry and instead worked in scientific lecturing and journalism, acting for a time as editor of a Fifeshire newspaper. In 1843 Page became the Scientific Editor to W. & R. Chambers, publishers in Edinburgh. He is supposed to have assisted Robert Chambers in writing the ''Vestiges of the Natural History of Creation''. He was recruited to Chambers in 1843, while ''Vestiges'', published 1844, was being written. His role is said, in fact, to have been to correct mistakes in science, in the first few editions. Later Page was in dispute with Chambers over his conditions of employment, wishing to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old Red Sandstone
The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also extends northwards into Greenland and Svalbard. These areas were a part of the ancient continent of Euramerica, Euramerica/Laurussia. In Britain it is a lithostratigraphy, lithostratigraphic unit (a sequence of rock strata) to which Stratigraphy, stratigraphers accord Geological unit#Lithostratigraphic units, supergroup status and which is of considerable importance to early paleontology. For convenience the short version of the term, ORS is often used in literature on the subject. The term was coined to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain. Sedimentology The Old Red Sandstone describes a suite of sedimentary rocks deposited in a variety of environments during the Devonian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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