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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 of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Furongian
The Furongian is the fourth and final epoch and series of the Cambrian. 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 10th stage of the Cambrian. 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' in Mandarin and refers to Hunan which is known as the "lotus state". Definition The lower boundary is defined in the same way as the GSSP of the Paibian Stage. Both begin with the first appearance of the trilobite ''Glyptagnostus reticulatus'' around million years ago. The upper boundary is the lower boundary and GSSP of the Tremadocian Stage which is the first appearance of the conodont ''Iapetognathus f ... [...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 physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compared to 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 The origins of the concept of neoteny have been traced to the Bible (as argued by Ashley Montag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. 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 anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protaspis
''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 state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi .... 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 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 At ... 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'' Shirley, 1936. 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 blumenb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calymenidae
Calymenidae is a family of 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 ...s, 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 Calymenina Trilobite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calymene
''Calymene'' Brongniart, 1822, 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. 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. *†''Calymen ... [...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- ... [...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 pygidia 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 Cheirurinae 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 genera ... [...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 * ''Trilobite: Eyewitness to Evolution'' by Richard Fortey External links Trilobites.info in the Paleobiology Database
The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.
History
The Paleobiology Database (PBDB) originated in the ...
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Dalmanitidae
Dalmanitidae is a family of trilobites in the order Phacopida that lived from the Floian The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician epoch. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from to million years ago. The ... (Ordovician) to the Devonian and includes 33 genera. References 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] |
