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Chondrenchelyiformes
Chondrenchelyiformes is an extinct order of holocephalan cartilaginous fish, known from the Early Carboniferous of Europe and North America. There are currently two recognised genera known from largely complete remains, ''Chondrenchelys'' from the Visean of Scotland, and ''Harpagofututor'' from the Serpukhovian aged Bear Gulch Limestone of Montana, United States. Both genera have elongate, eel-like bodies, with their mouths having tooth plates similar to those of living chimaeras, to which they share numerous anatomical similarities indicating a close relationship. Isolated tooth plates assigned to the genus '' Platyxystrodus'' likely belong to members of the family, which would extend the range of the group into the late Carboniferous. Anatomy Chondrenchelyiformes generally have elongate bodies with tapered heads, the lower jaw (mandible) is elongate, and articulates with the quadrate bone of the skull below the posteior edge of the eye socket. The dentition is composed of toot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocephalan
Holocephali (Sometimes spelled Holocephala; Romanization of Greek, Greek for "complete head" in reference to the fusion of Palatoquadrate, upper jaw with the rest of the skull) is a Subclass (biology), subclass of Chondrichthyes, cartilaginous fish. While the only living holocephalans are three families within a single Order (biology), order which together are commonly known as chimaeras, the group includes many extinct orders and was far more diverse during the Paleozoic and Mesozoic Era (geology), eras. The earliest known fossils of holocephalans date to the Middle Devonian period, and the group likely reached its peak diversity during the following Carboniferous period. Molecular clock studies suggest that the subclass diverged from its closest relatives, Elasmobranchii, elasmobranchs such as sharks and Batomorphi, rays, during the Early Devonian or Silurian period. Extinct holocephalans are typically divided into a number of orders, although the interrelationships of these gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrenchelys
''Chondrenchelys'' is an extinct genus of cartilaginous fish and the earliest member of Holocephali known from complete skeletons. ''Chondrenchelys'' would have been quite a relatively medium-sized fish with an elongated body up to in length, it had a dorsal fin which was indeed long and a body which tapered to a point. ''Chondrenchelys'' had one large pair, one middle-sized pair, and three small pair of tooth plates in each jaw. The genus name derives from the Greek word ''χόνδρος'', meaning “gristle” or “cartilage”, and ''ἔγχελυς'', meaning “eel”. The speciea name, ''problematicus'', is likely derived from the lack of scales setting it apart from all other fish known at the time of discovery. See also * List of prehistoric cartilaginous fish This list of prehistoric cartilaginous fish genera is an attempt to create a comprehensive listing of all Genus, genera that have ever been included in the class chondrichthyes ''and'' are known from the fossi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bear Gulch Limestone
The Bear Gulch Limestone is a limestone-rich Lens (geology), geological lens in central Montana, renowned for the quality of its marine fossils from the late Mississippian (geology), Mississippian subperiod, about 324 million years ago. It is exposed over a number of outcrops northeast of the Big Snowy Mountains, and is often considered a component of the more widespread Heath Formation. The Bear Gulch Limestone reconstructs a diverse, though isolated, marine ecosystem which developed near the end of the Serpukhovian age in the Carboniferous period. It is a lagerstätte, a particular type of rock unit with exceptional fossil preservation of both articulated skeletons and soft tissues. Bear Gulch fossils include a variety of fish, invertebrates, and algae occupying a number of different habitats within a preserved shallow bay. Fish include a high diversity of unusual Chondrichthyes, chondrichthyans (cartilaginous fish) and one of the oldest known lampreys, along with other vertebrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harpagofututor Volsellorhinus
''Harpagofututor'' is an extinct genus of eel-like cartilaginous fish from the Early Carboniferous ( Mississippian). It is primarily known from complete specimens discovered in the Bear Gulch Limestone of Montana, as well as an isolated tooth from Whitrope, Scotland. Discovery and taxonomy ''Harpagofututor'' was first described in 1982, from several complete specimens discovered in the Bear Gulch Limestone of Montana by Adelphi University palaeontologist Richard Lund.Lund, Richard. "Harpagofututor volsellorhinus New Genus and Species (Chondrichthyes, Chondrenchelyiformes) from the Namurian Bear Gulch Limestone, Chondrenchelys problematica Traquair (Visean), and Their Sexual Dimorphism," ''Journal of Paleontology'', Vol. 56, No. 4, July 1982, pp. 938-958. There is only one named species, ''H. volsellorhinus'', which was described by Lund in 1982. A single specimen of indeterminate species is also known from a single tooth plate discovered in Whitrope, Scotland. The genus is pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Carboniferous
Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican dancehall and reggae deejay Earlando Arrington Neil (1957–1994) * Early James, stage name of American singer-songwriter Fredrick Mullis Jr. (born 1993) * Early (Scritti Politti album), ''Early'' (Scritti Politti album), 2005 * Early (A Certain Ratio album), ''Early'' (A Certain Ratio album), 2002 * Early Records, a record label Other uses * Early (name), a list of people and fictional characters with the given name or surname * Early effect, an effect in transistor physics * Early, a synonym for ''hotter'' in Stellar classification#"Early" and "late" nomenclature, stellar classification See also * * The Earlies, a 21st century band * Earley (other) * Earlie, a given name {{disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serpukhovian
The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from Ma to Ma. It is preceded by the Visean and is followed by the Bashkirian. The Serpukhovian correlates with the lower part of the Namurian Stage of European stratigraphy and the middle and upper parts of the Chesterian Stage of North American stratigraphy. Name and definition The Serpukhovian Stage was proposed in 1890 by Russian stratigrapher Sergei Nikitin and was introduced in the official stratigraphy of European Russia in 1974. It was named after the city of Serpukhov, near Moscow. The ICS later used the upper Russian subdivisions of the Carboniferous in its international geologic time scale. The base of the Serpukhovian is informally defined by the first appearance of the conodont '' Lochriea ziegleri'', though the utility and systematic stability of this species is not yet certain. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chimaera
Chimaeras are Chondrichthyes, cartilaginous fish in the order (biology), order Chimaeriformes (), known informally as ghost sharks, rat fish (not to be confused with rattails), spookfish, or rabbit fish; the last two names are also applied to Barreleye, Opisthoproctidae and Rabbitfish, Siganidae, respectively. At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks and ray (fish), rays, though their last common ancestor with them lived nearly 400 million years ago. Living species (aside from plough-nose chimaeras) are largely confined to deep water. Anatomy Chimaeras are soft-bodied, shark-like fish with bulky heads and long, tapered tails; measured from the tail, they can grow up to in length. Like other members of the class Chondrichthyes, chimaera skeletons are entirely cartilaginous, or composed of cartilage. Males use forehead denticles to grasp a female by a fin during copulation. The Branchial arch, gill arche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clasper
In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's cloaca during mating. The act of mating in some fish including sharks usually includes one of the claspers raised to allow water into the siphon through a specific orifice. The clasper is then inserted into the cloaca, where it opens like an umbrella to anchor its position. The siphon then begins to contract, expelling water and sperm. The claspers of many shark species have spines or hooks, which may hold them in place during copulation. Many male holocephalans, including living chimaeras, have cephalic claspers (tenacula) on their heads, which are thought to aid in holding the female during mating. In entomology Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos'') ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
