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Drepanopteridae
''Drepanopterus'' is an extinct genus of eurypterid and the only member of the family Drepanopteridae within the Mycteropoidea superfamily. There are currently three species assigned to the genus. The genus has historically included more species, with nine species associated with the genus ''Drepanopterus'', however five of these have since been proven to be synonyms of pre-existing species, assigned to their own genera, or found to be based on insubstantial fossil data. The holotype of one species proved to be a lithic clast. ''Drepanopterus pentlandicus'' was first described from the Silurian strata of the Pentland Hills in Scotland. The only other fully described valid species is ''Drepanopterus abonensis'', from the Upper Devonian of Portishead, Somerset. The exact relationship of ''Drepanopterus'' to other Eurypterids has long been unclear, however it is now apparent that it is a primitive mycteropoid, and an early relative of the Carboniferous ''Hibbertopterus''. Descripti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycteropoidea
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 o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drepanopterus Size
''Drepanopterus'' is an extinct genus of eurypterid and the only member of the family Drepanopteridae within the Mycteropoidea superfamily. There are currently three species assigned to the genus. The genus has historically included more species, with nine species associated with the genus ''Drepanopterus'', however five of these have since been proven to be synonyms of pre-existing species, assigned to their own genera, or found to be based on insubstantial fossil data. The holotype of one species proved to be a lithic clast. ''Drepanopterus pentlandicus'' was first described from the Silurian strata of the Pentland Hills in Scotland. The only other fully described valid species is ''Drepanopterus abonensis'', from the Upper Devonian of Portishead, Somerset. The exact relationship of ''Drepanopterus'' to other Eurypterids has long been unclear, however it is now apparent that it is a primitive mycteropoid, and an early relative of the Carboniferous ''Hibbertopterus''. Descripti ... [...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] |
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] |
Hibbertopterus
''Hibbertopterus'' is a genus of eurypterid, a group of extinct aquatic arthropods. Fossils of ''Hibbertopterus'' have been discovered in deposits ranging from the Devonian period in Belgium, Scotland and the United States to the Carboniferous period in Scotland, Ireland, the Czech Republic and South Africa. The type species, ''H. scouleri'', was first named as a species of the significantly different ''Eurypterus'' by Samuel Hibbert in 1836. The generic name ''Hibbertopterus'', coined more than a century later, combines his name and the Greek word πτερόν (''pteron'') meaning "wing". ''Hibbertopterus'' was the largest eurypterid within the stylonurine suborder, with the largest fossil specimens suggesting that ''H. scouleri'' could reach lengths around 180–200 centimetres (5.9–6.6 ft). Though this is significantly smaller than the largest eurypterid overall, ''Jaekelopterus'', which could reach lengths of around , ''Hibbertopterus'' is likely to have been the h ... [...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] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypterina
Eurypterina is one of two suborders of eurypterids, an extinct group of chelicerate arthropods commonly known as "sea scorpions". Eurypterine eurypterids are sometimes informally known as "swimming eurypterids". They are known from fossil deposits worldwide, though primarily in North America and Europe. Seventy-five percent of eurypterid species are eurypterines; this represents 99% of specimens. The superfamily Pterygotioidea is the most species-rich clade, with 56 species, followed by the Adelophthalmoidea with 43 species; as sister taxa, they comprise the most derived eurypterines. Pterygotioidea includes the pterygotids, which are the only eurypterids known to have a cosmopolitan distribution. Though more numerous both in specimens and taxa, the eurypterines have the shorter temporal range of the two eurypterid suborders. They first appeared around the same time as the Stylonurina in the Middle Ordovician. The suborder faced a slow extinction during the Middle and Late Devo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanahughmilleria
''Nanahughmilleria'' ("dwarf ''Hughmilleria''") is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of ''Nanahughmilleria'' have been discovered in deposits of Devonian and Silurian age in the United States, Norway, Russia, England and Scotland, and have been referred to several different species. ''Nanahughmilleria'' is classified in the family Adelophthalmidae, the only clade in the superfamily Adelophthalmoidea. This clade was characterised by their small size, their parabolic (approximately U-shaped) carapaces and the presence of epimera (lateral "extensions" of the segment) on the seventh segment, among others. ''Nanahughmilleria'' was different from its relatives by the presence of more spines in its appendages (limbs) and by its genital morphology. The largest species confidently assigned to the genus was ''N. norvegica'' at 10 cm (3.9 in), making it a comparatively small eurypterid. Description Like the other adelophthalmid eurypterids, ''Nanahug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithic Fragment (geology)
Lithic fragments, or lithics, are pieces of other rocks that have been eroded down to sand size and now are sand grains in a sedimentary rock. They were first described and named (in their modern definitions) by Bill Dickinson in 1970. Lithic fragments can be derived from sedimentary, igneous or metamorphic rocks. A lithic fragment is defined using the Gazzi-Dickinson point-counting method and being in the sand-size fraction. Sand grains in sedimentary rocks that are fragments of larger rocks that are not identified using the Gazzi-Dickinson method are usually called rock fragments instead of lithic fragments. Sandstones rich in lithic fragments are called lithic sandstones.Lithic fragments can also be define as the breakdown of preexisting ,fine -to medium grained igneous . metamorphic and sedimentary rocks results in sand -sized fragments.. Types Igneous (Lv) These can include granular (~rhyolitic), microlitic (~andesitic), lathwork (~basaltic), and vitric ( glassy). These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kokomopterus
''Kokomopterus'' is a genus of prehistoric eurypterid. The genus contains a single species, ''Kokomopterus longicaudatus'', known from the Silurian of Kokomo, Indiana.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). See also * 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 conside ... References Stylonurina Silurian eurypterids Silurian arthropods of North America Eurypterids of North America {{eurypterid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
