|
Phacopida Genera
Phacopida ("lens-face") is an order of trilobites that lived from the Late Cambrian to the Late Devonian. It is made up of a morphologically diverse assemblage of taxa in three related suborders. Characteristics Phacopida had 8 to 19 thoracic segments and are distinguishable by the expanded glabella, short or absent preglabellar area, and schizochroal (Phacopina) or holochroal (Cheirurina and Calymenina) eyes. Schizochroal eyes are compound eyes with up to around 700 separate lenses. Each lens has an individual cornea which extended into a rather large sclera. The development of schizochroal eyes in phacopid trilobites is an example of post-displacement paedomorphosis. The eyes of immature holochroal Cambrian trilobites were basically miniature schizochroal eyes. In Phacopida, these were retained, via delayed growth of these immature structures (post-displacement), into the adult form. '' Eldredgeops rana'' (Phacopidae) and ''Dalmanites limulurus'' (Dalmanitidae) are two o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furongian
The Furongian is the fourth and final epoch and series of the Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov .... It lasted from to million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three stages: the Paibian, Jiangshanian and the unnamed Cambrian Stage 10, 10th stage of the Cambrian. History and naming The Furongian was also known as the Cambrian Series 4, and the name replaced the older term Upper Cambrian and equivalent to the local term Hunanian. The present name was ratified by the International Commission on Stratigraphy in 2003. () means 'lotus (genus), lotus' in Mandarin and refers to Hunan which is known as the "lotus state". Definition The lower boundary is defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paedomorphosis
Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the Physiology, physiological, or Somatic (biology), somatic, development of an organism, typically an animal. Neoteny in humans, Neoteny in modern humans is more significant than in other primates. In progenesis or paedogenesis, sexual development is accelerated. Both neoteny and progenesis result in paedomorphism (as having the form typical of children) or paedomorphosis (changing towards forms typical of children), a type of heterochrony. It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication, and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders.Schell, S. C. ''Handbook of Trematodes of North America North of Mexico'', 1985, pg. 22 History and etymology Julius Kollmann created the term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Termi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protaspis (trilobite)
''Protaspis'' is an extinct genus of pteraspidid heterostracan agnathan which lived during the Early Devonian of the United States, with fossils found in marine strata in what is now Utah, Wyoming and Idaho Idaho ( ) is a landlocked U.S. state, state in the Pacific Northwest and Mountain states, Mountain West subregions of the Western United States. It borders Montana and Wyoming to the east, Nevada and Utah to the south, and Washington (state), .... References Pteraspidiformes genera Devonian jawless fish Devonian fish of North America Fossils of the United States {{Devonian-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceraurinella
''Ceraurinella'' is an extinct genus of trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ... in the family Cheiruridae. There are about 19 described species in ''Ceraurinella''. Species These 19 species belong to the genus ''Ceraurinella'': * † ''Ceraurinella arctica'' Ludvigsen, 1979 * † ''Ceraurinella brevispina'' Ludvigsen, 1979 * † ''Ceraurinella buttsi'' Cooper * † ''Ceraurinella chondra'' Whittington & Evitt, 1953 * † ''Ceraurinella kingstoni'' Chatterton & Ludvigsen, 1976 * † ''Ceraurinella latipyga'' Shaw, 1968 * † ''Ceraurinella longispina'' Ludvigsen, 1979 * † ''Ceraurinella media'' Ludvigsen, 1979 * † ''Ceraurinella nahanniensis'' Chatterton & Ludvigsen, 1976 * † ''Ceraurinella necra'' Ludvigsen, 1979 * † ''Ceraurinella oepiki'' Edgecombe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flexicalymene
''Flexicalymene'' is a genus of trilobites belonging to the order Phacopida, suborder Calymenina and family Calymenidae. ''Flexicalymene'' specimens can be mistaken for ''Calymene'', '' Gravicalymene'', '' Diacalymene'' and a few other Calymenina genera. They are used as an index fossil in the Ordovician. Ohio and North America are particularly known for being rich with ''Flexicalymene'' fossils. Diagnosis "Glabella parabolic to bell-shaped in outline, with three or four lateral lobes and furrows. Lacks buttress(es) from fixed cheek to lateral glabellar lobe(s). Does not have preglabellar field. No distinct crescentic area outside lateral lobe l p. Facial sutures gonatoparian (exceptionally, can be proparian in Flexicalymene). Genal spines absent. Hypostome without discrete protuberance on anterior lobe of median body." (Siveter, 1976, p. 353) Type species * ''Flexicalymene caractaci'' ( Salter, 1865). By original designation and by monotypy, ''Calymene blumenbachii'' var. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calymenidae
Calymenidae is a family (biology), family of trilobites, containing the following genera: *''Alcymene'' *''Apocalymene'' *''Arcticalymene'' *''Calymene'' *''Calymenella'' *''Calymenesum'' *''Colpocoryphe'' *''Dekalymene'' *''Diacalymene'' *''Flexicalymene'' *''Gravicalymene'' *''Limbocalymene'' *''Linguocalymene'' *''Liocalymene'' *''Metacalymene'' *''Neseuretinus'' *''Neseuretus'' *''Nipponocalymene'' *''Onnicalymene'' *''Papillicalymene'' *''Paracalymene'' *''Platycalymene'' *''Pradoella'' *''Protocalymene'' *''Reacalymene'' *''Reedocalymene'' *''Salterocoryphe'' *''Sarrabesia'' *''Spathacalymene'' *''Sthenarocalymene'' *''Tapinocalymene'' *''Thelecalymene'' *''Vietnamia'' References Calymenidae, Calymenina Trilobite families {{Phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calymene
''Calymene'' is a genus of trilobites in the order Phacopida, suborder Calymenina, that are found throughout North America, North Africa, and Europe in primarily Silurian outcrops. ''Calymene'' is closely related to ''Flexicalymene'', and both genera are frequently found enrolled. Calymene trilobites are small, typically 2 cm in length. The cephalon is the widest part of the animal and the thorax usually has 13 segments. The correct genus authorship is Brongniart (1822). A previously published genus description in Desmarest (1816) (often mis-cited as "Calymena" Desmarest, 1817) was suppressed by ICZN Opinion 1433. Etymology ''Calymene'' - meaning ''beautiful crescent'' as a reference to the Glabella (trilobite anatomy), glabella. Known species and locations *†''Calymene blumenbachii'', Dudley, England - Type *†''Calymene brevicapitata'', N. and S. Wales *†''Calymene breviceps'', Indiana and Illinois *†''Calymene celebra'', Illinois, Indiana, and Wisconsin. *† ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deiphon
''Deiphon'' is a distinctive genus of Silurian phacopid trilobites of the family Cheiruridae found in Western and Central Europe, and in Central and Eastern United States. The type species, ''D. forbesi'', from England, Bohemia, and Sweden, was discovered and described by the French paleontologist, Joachim Barrande in 1850. Description The glabella was inflated, and globular-shaped, and covered in small wart-like bumps. If it was filled with fat, or oil, the glabellum would have helped to have made the creature positively buoyant. On the other hand, trilobites with large glabellae are often suspected of being predatory, as the volume of glabella would be filled with digestive organs, or used to store captured/swallowed prey. The free cheeks of the cephalon formed a pair of long, curved spines, and the segments of the pleural lobes were separated and elongated to form rib-like struts. These modifications, along with the V-shaped pygidium give these trilobites a cartoon "fish-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheiruridae
Cheiruridae is a family of phacopid trilobites of the suborder Cheirurina. Its members, as with other members of the suborder, had distinctive pygidial modified into finger-like spines. They first appeared in the uppermost Cambrian (upper Furongian), and persisted until the end of the Middle Devonian (Givetian). Currently about 657 species assigned to 99 genera are included. Distribution The subfamily Cheirurina with 269 species in 38 genera occur from the Floian to the Givetian and are probably monophyletic. The 109 species in 15 genera of the Acanthoparyphinae are also probably monophyletic, and are known from the Floian to the Ludfordian. The Cyrtometopinae were present between the Floian and the Upper Katian, enveloping 22 species in 5 genera, of which the monophyly is unclear. The Deiphoninae are probably monophyletic, occur from the Dapingian to the Gorstian, having 71 species assigned to 6 genera. The possibly paraphyletic Eccoptochilinae with 67 species in 13 gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheirurus
''Cheirurus'' (from Greek ''χείρ, cheir'' meaning "hand" and ''ουρά, oura'' meaning "tail") is a genus of phacopid trilobites that lived from the Ordovician to the Devonian. Its remains have been found in Africa, Asia, Australia, Europe, and North America. ''Cheirurus'' is the type genus of Cheiruridae. References Further reading * ''Trilobite: Eyewitness to Evolution'' by Richard Fortey Richard Alan Fortey (15 February 1946 – 7 March 2025) was a British palaeontologist, natural historian, writer and television presenter, who served as president of the Geological Society of London for its bicentennial year of 2007. As a paleo ... External links * * Cheiruridae Phacopida genera Ordovician trilobites Silurian trilobites Devonian trilobites Trilobites of Africa Trilobites of Asia Trilobites of Oceania Trilobites of Europe Trilobites of North America Fossil taxa described in 1845 Middle Devonian genus extinctions Paleozoic life of Ontario Paleo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalmanitidae
Dalmanitidae is a family of trilobites in the order Phacopida that lived from the Floian (Ordovician) to the Devonian and includes 33 genera. References Dalmanitidae, Dalmanitoidea Trilobite families Early Ordovician first appearances Devonian extinctions Fossils of Georgia (U.S. state) {{phacopida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
