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Pseudoasaphus
''Pseudoasaphus'' is an extinct genus of trilobites from the Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. .... References Asaphidae Asaphida genera Taxa described in 1904 {{Asaphida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asaphidae
Asaphidae is a family of asaphid trilobites. Although the first genera originate in Upper Cambrian marine strata, the family becomes the most widely distributed and most species-rich trilobite family during the Ordovician. 754 species assigned to 146 genera are included in Asaphidae. Distribution Most Asaphinae are characteristic of Baltica. Isotelinae genera are concentrated in Laurentia. The genera of Nobiliasaphinae are distributed in tropical Gondwana and South China. The genera of Ogygiocaridinae occur in Avalonia, Gondwana and Baltica. Asaphidae asaphids were already fairly common during the Upper-Cambrian, when 14 genera are known from Australia, North- and South-China. The last members of the family died-out at the end of the Ordovician. Assigned genera Asaphidae contains the following genera: *'' Anataphrus'' *'' Araiocaris'' *'' Asaphellus'' *'' Asaphus'' *'' Atopasaphus'' *'' Aulacoparia'' *'' Aulacoparina'' *'' Australopyge'' *'' Baltiites'' *'' Banqiaoites'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trilobite
Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period () and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. By the time trilobites first appeared in the fossil record, they were already highly diversified and geographically dispersed. Because trilobites had wide diversity and an easily fossilized exoskeleton, they left an extensive fossil record. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively. Lapworth recognized that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian systems, and placed them in a system of their own. The Ordovician received international approval in 1960 (forty years after Lapworth's death), when it was adopted as an official period of the Paleozoic Era by the International Geological Congress. Life continued to flourish during the Ordovician as it did in the earlier C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asaphida Genera
Asaphida is a large, morphologically diverse order (biology), order of trilobites found in marine Stratum, strata dated from the Middle Cambrian until their extinction during the Silurian. Asaphida contains six Superfamily (zoology), superfamilies (Anomocaroidea, Asaphoidea, Cyclopygoidea, Dikelocephaloidea, Remopleuridoidea and Trinucleioidea), but no suborders. Asaphids comprise some 20% of described fossil trilobites. In 2020, the superfamily Trinucleoidea was proposed to be raised to an order (Trinucleida) and removed from Asaphida. Morphology The Asaphids generally have cephalon (arthropod anatomy), cephalon (head) and pygidium (tail) parts similar in size, and most species have a prominent median ventral suture. Heads are often flat, and carapace furrows in the head area are often faint or not visible. Thoracic segments typically number 5 - 12, though some species have as few as two and some as many as 30. They also generally have a wide doublure, or rim, that surrounds t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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