|
Chimaeroidei
Chimaeras are cartilaginous fish in the 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 Opisthoproctidae and Siganidae, respectively. At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks and 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 gill arches are condensed into a pouch-like bundle covered by a sheet of skin (an opercul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protochimaera
''Protochimaera'' is an extinct genus of chimaeriform fish from the Mississippian (Early Carboniferous) of central Russia. It is the oldest known representative of the order Chimaeriformes, approximately 10 million years older than ''Echinochimaera'' (from the late Serpukhovian of Montana), and far older than the Mesozoic radiation which would lead to modern chimaeriforms, commonly known as chimaeras, rat fish, or ghost sharks. ''Protochimaera'' is known from tooth plates found at five sites southwest of the Moscow Basin. These sites correspond to the Olkhovets Formation (Tulian and Aleksinian regional stages, equivalent to the middle of the global Viséan stage) and Dashkovo Formation (Steshevian regional stage, the lower-middle part of the Serpukhovian). Like modern chimaeras (Chimaeroidei), there are three pairs of tooth plates, each developing a cutting or shearing edge. This degree of similarity suggests that ''Protochimaera'' is the sister taxon to Chimaeroidei, a propos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squaloraja
''Squaloraja'' (Latin for "shark- skate") is an extinct genus of ray-like marine chimaeriform fish from the Early Jurassic of Europe. Taxonomy It contains a single named species known from the Sinemurian-aged Blue Lias of Lyme Regis, England: ''S. polyspondyla'' Agassiz, 1836, with complete specimens representing both males and females. A second species from the same locality, ''S. tenuispina'' Woodward, 1886 (known from an isolated horn of a male), is now considered conspecific with ''S. polyspondyla''. In addition, the complete specimen of the female of an indeterminate species is known from the Sinemurian-aged Moltrasio Formation of Osteno, Italy, and indeterminate teeth are known from the earlier Hettangian of Belgium. Divergence estimates suggest that ''Squaloraja'' was a relict taxon and the last surviving member of a chimaera lineage that had diverged from the Chimaeroidei by the late Mississippian stage of the Carboniferous period, as stem-chimaeroids already app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myriacanthidae
Myriacanthidae is an extinct family of holocephalan cartilaginous fish, closely related to living chimaeras. Fossils are known from the latest Triassic (Rhaetian) and Early Jurassic of Europe. Description Like other cartilaginous fish, most myriacanthids are only known from their teeth (and in a few cases their fin spines), though a handful of species are known from partial skeletons which preserve the cartilage. Members of Myriacanthidae generally have elongate rostra with long frontal claspers. On the lower jaw, there is a dermal plate, and parts of the head are covered in dermal plates in some genera. There are three pairs of tooth plates in the upper jaw, of which the pair furthest back in the mouth are the largest. Like other members of Myriacanthoidei, they have dorsal fins supported by fin spines which are ornamented with tubercles. The synarcual is articulated with a basal cartilage. The notochord is surrounded by calcified rings (or alternatively paired half rings). T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolagus Colliei
The spotted ratfish (''Hydrolagus colliei'') is a chimaera found in the north-eastern Pacific Ocean. Often seen by divers at night in the Pacific Northwest, this cartilaginous fish gets its characteristic name from a pointed rat-like tail. The ratfish lays leathery egg case (Chondrichthyes), egg cases on the bottom of muddy or sandy areas, which are often mistaken by divers as something inanimate. While mainly a deep-water species, it occurs at shallower depths in the northern part of its range. The generic name, ''Hydrolagus'', comes from the Greek words ὕδωρ, meaning water,Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with the assistance of. Roderick McKenzie.'' Oxford: Clarendon Press. and λαγώς/λαγῶς, meaning hare, and the specific name honors Alexander Collie, who was a ship surgeon and early naturalist. The spotted ratfish is common in much of its range, not typically eaten by humans, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (: branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamella (surface anatomy), lamellae (folds) contain blood or Coelom#Coelomic fluid, coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including Mollusc, molluscs, crustaceans, insects, fish, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Sea Chimaera
Deep or The Deep may refer to: Places United States * Deep Creek (Appomattox River tributary), Virginia * Deep Creek (Great Salt Lake), Idaho and Utah * Deep Creek (Mahantango Creek tributary), Pennsylvania * Deep Creek (Mojave River tributary), California * Deep Creek (Pine Creek tributary), Pennsylvania * Deep Creek (Soque River tributary), Georgia * Deep Creek (Texas), a tributary of the Colorado River * Deep Creek (Washington), a tributary of the Spokane River * Deep River (Indiana), a tributary of the Little Calumet River * Deep River (Iowa), a minor tributary of the English River * Deep River (North Carolina) * Deep River (Washington), a minor tributary of the Columbia River * Deep Voll Brook, New Jersey, also known as Deep Brook Elsewhere * Deep Creek (Bahamas) * Deep Creek (Melbourne, Victoria), Australia, a tributary of the Maribyrnong River * Deep River (Western Australia) People * Deep (given name) * Deep (rapper), Punjabi rapper from Houston, Texas * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartilage
Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck and the bronchial tubes, and the intervertebral discs. In other taxa, such as chondrichthyans and cyclostomes, it constitutes a much greater proportion of the skeleton. It is not as hard and rigid as bone, but it is much stiffer and much less flexible than muscle. The matrix of cartilage is made up of glycosaminoglycans, proteoglycans, collagen fibers and, sometimes, elastin. It usually grows quicker than bone. Because of its rigidity, cartilage often serves the purpose of holding tubes open in the body. Examples include the rings of the trachea, such as the cricoid cartilage and carina. Cartilage is composed of specialized c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branchial Arch
Branchial arches or gill arches are a series of paired bony/ cartilaginous "loops" behind the throat ( pharyngeal cavity) of fish, which support the fish gills. As chordates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arches varies between taxa. In all jawed fish (gnathostomes), the first arch pair (mandibular arches) develops into the jaw, the second gill arches (the hyoid arches) develop into the hyomandibular complex (which supports the back of the jaw and the front of the gill series), and the remaining posterior arches (simply called branchial arches) support the gills. In tetrapods, a mostly terrestrial clade evolved from lobe-finned fish, many pharyngeal arch elements are lost, including the gill arches. In amphibians and reptiles, only the oral jaws and a hyoid apparatus remains, and in mammals and birds the hyoid is simplified further to support the tongue and floor of the mouth. In mammals, the first and second pharyng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (fish)
The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bone segments known as the preoperculum, suboperculum, interoperculum and operculum. The preoperculum is a crescent-shaped structure that has a series of ridges directed posterodorsally to the organism’s canal pores. The preoperculum can be located through an exposed condyle that is present immediately under its ventral margin; it also borders the operculum, suboperculum, and interoperculum posteriorly. The suboperculum is rectangular in shape in most bony fish and is located ventral to the preoperculum and operculum components. It is the thinnest bone segment out of the opercular series and is located directly above the gills. The interoperculum is triangular shaped and borders the suboperculum posterodorsally and the preoperculum anterodo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anal Fin
Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only by muscles. Fish fins are distinctive anatomical features with varying structures among different clades: in ray-finned fish (Actinopterygii), fins are mainly composed of bony spines or rays covered by a thin stretch of scaleless skin; in lobe-finned fish ( Sarcopterygii) such as coelacanths and lungfish, fins are short rays based around a muscular central bud supported by jointed bones; in cartilaginous fish ( Chondrichthyes) and jawless fish ( Agnatha), fins are fleshy " flippers" supported by a cartilaginous skeleton. Fins at different locations of the fish body serve different purposes, and are divided into two groups: the midsagittal ''unpaired fins'' and the more laterally located ''paired fins''. Unpaired fins are pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pectoral Fin
Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column, back bone and are supported only by muscles. Fish fins are distinctive anatomical features with varying structures among different clades: in ray-finned fish (Actinopterygii), fins are mainly composed of bone, bony spine (zoology), spines or ray (fish fin anatomy), rays covered by a thin stretch of fish scale, scaleless skin; in lobe-finned fish (Sarcopterygii) such as coelacanths and lungfish, fins are short rays based around a muscular central limb bud, bud supported by appendicular skeleton, jointed bones; in cartilaginous fish (Chondrichthyes) and jawless fish (Agnatha), fins are fleshy "flipper (anatomy), flippers" supported by a cartilaginous skeleton. Fins at different locations of the fish body serve different purposes, and are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelvic Fin
Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hindlimbs of tetrapods, which evolved from lobe-finned fish during the Middle Devonian. Structure and function Structure In actinopterygians, the pelvic fin consists of two endochondrally-derived bony girdles attached to bony radials. Dermal fin rays ( lepidotrichia) are positioned distally from the radials. There are three pairs of muscles each on the dorsal and ventral side of the pelvic fin girdle that abduct and adduct the fin from the body. Pelvic fin structures can be extremely specialized in actinopterygians. Gobiids and lumpsuckers modify their pelvic fins into a sucker disk that allow them to adhere to the substrate or climb structures, such as waterfalls. In priapiumfish, males have modified their pelvic structures into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
