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Agnostidae
Agnostidae is a family (biology), family of Agnostida trilobites. Like all Agnostina, they were eyeless and had only two thorax, thoracic segments. These trilobites inhabited benthic waters worldwide from 508 to 461 million years ago. The family includes the following genera, among others: *''Acmarhachis'' *''Agnostus'' *''Aistagnostus'' *''Anglagnostus'' *''Biciragnostus'' *''Connagnostus'' *''Distagnostus'' *''Eolotagnostus'' *''Gymnagnostus'' *''Homagnostus'' *''Idolagnostus'' *''Innitagnostus'' *''Ivshinagnostus'' *''Kymagnostus'' *''Lotagnostus'' *''Micragnostus'' *''Obelagnostus'' *''Oncagnostus'' *''Phalacroma'' *''Phalagnostus'' *''Quadrahomagnostus'' *''Raragnostus'' *''Semagnostus'' *''Strictagnostus'' *''Trilobagnostus'' References Agnostidae, Agnostoidea Trilobite families Cambrian first appearances Middle Ordovician extinctions {{agnostida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnostus
''Agnostus'' is a genus of agnostid trilobites, belonging to the family Agnostidae, that lived during the late Middle Cambrian – Upper Cambrian (about 506 to 485 million years ago). It is the type genus of the family (biology), family Agnostidae and is subdivided into two subgenera, ''Agnostus'' and ''Homagnostus''. Etymology ''Agnostus'' is from the Ancient Greek άγνωστος (''ágnostos'') "unknown", and reflects the fact that early paleontologists did not know what type of animal with which they were confronted. The species epithet has this origin: * ''pisiformis'' derives from the Latin ''pīsum'' which means "pea", and ''forma'' meaning "shape", for its globe-like appearance when rolled. Description Like all Agnostida, ''Agnostus'' is diminutive and the headshield (or Cephalon (arthropod head)#Trilobites, cephalon) and tailshield (or pygidium) are around the same size (or Pygidium#Trilobites, isopygous) and outline. As in all Agnostina, ''Agnostus'' has two thor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homagnostus
''Homagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now north Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic .... It was described by Howell in 1935. The genus was originally considered to be ''Agnostus pisiformis var. obesus'' (Belt, 1867). P.A. Jell and J.M. Adrain. References Agnostidae Fossils of Wales[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eolotagnostus
''Eolotagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now Gansu, China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after .... It was described by Zhou in 1982, and the type species is ''Eolotagnostus gansuensis''. P.A. Jell and J.M. Adrain. References Agnostidae Fossils of China Agnost ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obelagnostus
''Obelagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. .... It was described by Shergold and Webers in 1992, and the type species is ''Obelagnostus imitor''. P.A. Jell and J.M. Adrain. References Agnostidae Trilobites of Antarctica[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micragnostus
''Micragnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now north Wales. It was described by Howell in 1935, and the type species is ''Micragnostus calvus'', which was originally described as a species of ''Agnostus ''Agnostus'' is a genus of agnostid trilobites, belonging to the family Agnostidae, that lived during the late Middle Cambrian – Upper Cambrian (about 506 to 485 million years ago). It is the type genus of the family (biology), family Agnostida ...'' by Lake in 1906. P.A. Jell and J.M. Adrain. References Agnostidae Trilobites of Europe[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lotagnostus
''Lotagnostus'' is a genus of very small trilobites in the order Agnostida, which lived on the outer continental shelves worldwide, during the late Upper Cambrian. It was described by Whitehouse in 1936, and the type species is ''Lotagnostus trisectus'', which was originally described as a species of ''Agnostus'' by Salter in 1864. Taxonomy The Treatise on Invertebrate Paleontology divides ''Lotagnostus'' into three subgenera that differ in the degree of effacement: ''L. (Lotagnostus)'' Whitehouse, 1936 (neither cephalon nor pygidium strongly effaced), ''L. (Distagnostus)'' Shergold, 1972 (strongly effaced on the outer/dorsal surface, but with clear furrows on the inner/ventral surface and ''L. (Eolotagnostus)'' Zhou ''in'' Zhiqiang Zhou, li & Qu, 1982 (with even the inner/ventral surface strongly effaced). Later authors however consider it likely that creating these subgenera would render the nominate subgenus paraphyletic. Biostratographic significance The first appearance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kymagnostus
''Kymagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ..., United States. It was described by Hohensee in 1989, and the type species is ''Kymagnostus harti''. P.A. Jell and J.M. Adrain. References Agnostidae Fossils of the United States[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivshinagnostus
''Ivshinagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th .... It was described by Ergaliev in 1980, and the type species is ''Ivshinagnostus ivshini''. P.A. Jell and J.M. Adrain. References Agnostidae Fossils of Kazakhstan[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Innitagnostus
''Innitagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now Queensland, Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl .... It was described by Öpik, 1967, and the type species is ''Innitagnostus innitens''. P.A. Jell and J.M. Adrain. References Agnostidae Agnostida genera[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Idolagnostus
''Idolagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now Queensland, Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl .... It was described by Öpik in 1967, and the type species is ''Idolagnostus agrestis''. P.A. Jell and J.M. Adrain. References Agnostidae Agnostida genera[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phalagnostus
''Phalagnostus'' is a genus of small trilobites, in the order Agnostida. It lived during the Middle Cambrian, in what are now Canada (Newfoundland and Northwest Territories), China, the Czech Republic, Denmark, England, France, the Russian Federation (Bennett Island, Yakutia), Wales, Sweden, and possibly the United States (Vermont). The headshield (or cephalon) is almost entirely effaced and wider than the tailshield (or pygidium). The pygidium is also very effaced, but the ovate pygidial axis (or rhachis) is well defined and a border furrow is also present. Taxonomy ''Phalagnostus nudus'', the type species, was originally described as a species of '' Battus'' by Beyrich in 1845, but that name had already been used for a butterfly, and the trilobite genus was also deemed polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnagnostus
''Gymnagnostus'' is a genus of trilobites in the order Agnostida, which existed in what is now Oaxaca Oaxaca, officially the Free and Sovereign State of Oaxaca, is one of the 32 states that compose the political divisions of Mexico, Federative Entities of the Mexico, United Mexican States. It is divided into municipalities of Oaxaca, 570 munici ..., Mexico. It was described by Robison and Pantoja-Alor, in 1968, and the type species is ''Gymnagnostus gongros''. P.A. Jell and J.M. Adrain. References Agnostidae Fossils of Mexico[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
