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Porolepiformes
Porolepiformes is an order of prehistoric lobe-finned fish which lived during the Devonian period (about 416 to 359 million years ago). They are thought to represent the sister group to lungfish (class Dipnoi). The group contains two families: Holoptychiidae and Porolepididae. Porolepiformes was established by the Swedish paleontologist Erik Jarvik, and were thought to have given rise to the salamanders and caecilians independently of the other tetrapods. He based this conclusion on the shapes of the snouts of the aforementioned groups. This view is no longer in favour in Paleontology Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure ge .... Jarvik also claimed the existence of choanae in porolepiformes which linked them to tetrapods, but this has remained controversial. Recent phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holoptychiidae
Porolepiformes is an Order (biology), order of prehistoric lobe-finned fish which lived during the Devonian geological period, period (about 416 to 359 million years ago). They are thought to represent the sister group to lungfish (class Dipnoi). The group contains two family (biology), families: Holoptychiidae and Porolepididae. Porolepiformes was established by the Swedish paleontologist Erik Jarvik, and were thought to have given rise to the salamanders and caecilians independently of the other tetrapods. He based this conclusion on the shapes of the snouts of the aforementioned groups. This view is no longer in favour in Paleontology. Jarvik also claimed the existence of choanae in porolepiformes which linked them to tetrapods, but this has remained controversial. Recent phylogenetic reconstruction places porolepiformes close to lungfishes. More recent evidence has shown that at least one genus ''Laccognathus'' was most likely amphibious fish, amphibious. Phylogeny Mikko' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porolepidae
Porolepiformes is an order of prehistoric lobe-finned fish which lived during the Devonian period (about 416 to 359 million years ago). They are thought to represent the sister group to lungfish (class Dipnoi). The group contains two families: Holoptychiidae and Porolepididae. Porolepiformes was established by the Swedish paleontologist Erik Jarvik, and were thought to have given rise to the salamanders and caecilians independently of the other tetrapods. He based this conclusion on the shapes of the snouts of the aforementioned groups. This view is no longer in favour in Paleontology. Jarvik also claimed the existence of choanae The choanae (: choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the pharynx, in humans and other mammals (as well as crocodilians and most skinks). They ... in porolepiformes which linked them to tetrapods, but this has remained controversial. Recent phylog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago (Megaannum, Ma), to the beginning of the succeeding Carboniferous period at Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of history of life#Colonization of land, life on land occurred during the Devonian, as free-spore, sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaf, leaves and true roots, and by the end of the period the first seed-bearing plants (Pteridospermatophyta, pteridospermatophyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lungfish
Lungfish are freshwater vertebrates belonging to the class Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods (which includes living amphibians, reptiles, birds and mammals). The mouths of lungfish typically bear tooth plates, which are used to crush hard shelled organisms. Today there are only six known species of lungfish, living in Africa, South America, and Australia, though they were formerly globally distributed. The fossil record of the group extends into the Early Devonian, over 410 million years ago. The earliest known members of the group were marine, while almost all post-Carboniferous representatives inhabit freshwater environments. Etymology Dipnoi is Modern Latin derived from the Greek δίπν ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porolepis Brevis
''Porolepis'' is an extinct genus of porolepiform sarcopterygian fish, from the Early Devonian Dniester Series of Ukraine, which is rich in ''Porolepis'' remains, and also the Nellen Koepfchen Beds of Germany. It lived alongside the dubious lophotrochozoan ''Macrodontophion''. It was first described in 1858 but ''Porolepis'' was not named as a sufficient species until 1891. A. S. Woodward. (1891) Catalogue of the Fossil Fishes in the British Museum (Natural History). Part II. ''Catalogue of the Fossil Fishes in the British Museum (Natural History)'' 2 See also * Sarcopterygii * List of sarcopterygians * List of prehistoric bony fish This list of prehistoric bony fish is an attempt to create a comprehensive listing of all Genus, genera from the fossil record that have ever been considered to be bony fish (class Osteichthyes), excluding purely vernacular terms. The list includ ... References Porolepiformes Prehistoric lobe-finned fish genera Early Devonian sarcopter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holoptychius Quebecensis -"salamanderfisk"
''Holoptychius'' (from , 'whole' and 'fold') is an extinct genus of porolepiform lobe-finned fish from the Middle Devonian to Carboniferous ( Mississippian) periods. It is known from fossils worldwide. The genus was first described by Louis Agassiz in 1839. Description ''Holoptychius'' was a streamlined predator about long (though largest specimen could grow up to ), which fed on other bony fish. Its rounded scales and body form indicate that it could have swum quickly through the water to catch prey. Similar to other rhipidistians, it had fang-like teeth on its palate in addition to smaller teeth on the jaws. Its asymmetrical tail sported a caudal fin on its lower end. To compensate for the downward push caused by this fin placement, the pectoral fins of ''Holoptychius'' were placed high on the body. Species Of the genus ''Holoptychius'' the following species have been described: * ''H. americanus'' * ''H. andersoni'' * ''H. bergmanni'' (Downs et al, 2013) from the Fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleontological Journal
''Paleontological Journal'' () is a monthly peer-reviewed Russian journal of paleontology Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure ge ... established in 1959. It focuses on the paleontology and the fossil records of Eastern Europe and Asia. Articles are published simultaneously in Russian and English. The journal is edited by Alexei Yu. Rozanov and published by MAIK Nauka/Interperiodica. Editors-in-Chief *Academician, Acad. Yuri Alexandrovich Orlov, Yuri A. Orlov (1959–1966) *Dr. Vasily Ruzhentsev, Vasily E. Ruzhentsev (1967–1978) *Acad. Leonid Petrovich Tatarinov, Leonid P. Tatarinov (1978–1988, 1994–2001) *Dr. Igor S. Barskov (1988–1993) *Acad. Alexei Yu. Rozanov (since 2001) Abstracting and indexing ''Paleonotological Journal'' is indexed and abstracted in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibious Fish
Amphibious fish are fish that are able to leave water for extended periods of time. About 11 distantly related genera of fish are considered amphibious. This suggests that many fish genera independently evolved amphibious traits, a process known as convergent evolution. These fish use a range of methods for land movement, such as lateral undulation, tripod-like walking (using paired fins and tail), and jumping. Many of these methods of locomotion incorporate multiple combinations of pectoral-, pelvic-, and tail-fin movement. Many ancient fish had lung-like organs, and a few, such as the lungfish and bichir, still do. Some of these ancient "lunged" fish were the ancestors of tetrapods. In most recent fish species, though, these organs evolved into the swim bladders, which help control buoyancy. Having no lung-like organs, modern amphibious fish and many fish in oxygen-poor water use other methods, such as their gills or their skin to breathe air. Amphibious fish may also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Choanae
The choanae (: choana), posterior nasal apertures or internal nostrils are two openings found at the back of the nasal passage between the nasal cavity and the pharynx, in humans and other mammals (as well as crocodilians and most skinks). They are considered one of the most important synapomorphies of tetrapodomorphs, that allowed the passage from water to land. In animals with secondary palates, they allow breathing when the mouth is closed. Janvier, Philippe (2004) "Wandering nostrils". ''Nature'', 432 (7013): 23–24. In tetrapods without secondary palates their function relates primarily to olfaction (sense of smell). The choanae are separated in two by the vomer. Boundaries A choana is the opening between the nasal cavity and the nasopharynx. It is therefore not a structure but a space bounded as follows: * anteriorly and inferiorly by the horizontal plate of palatine bone, * superiorly and posteriorly by the sphenoid bone * laterally by the medial pterygoid pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleontology
Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geologic time, and assess the interactions between prehistoric organisms and their natural environment. While paleontological observations are known from at least the 6th century BC, the foundation of paleontology as a science dates back to the work of Georges Cuvier in 1796. Cuvier demonstrated evidence for the concept of extinction and how life of the past was not necessarily the same as that of the present. The field developed rapidly over the course of the following decades, and the French word ''paléontologie'' was introduced for the study in 1822, which was derived from the Ancient Greek word for "ancient" and words describing relatedness and a field of study. Further advances in the field accompanied the work of Charles Darwin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapod
A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetrapoda (). Tetrapods include all Neontology#Extant taxa versus extinct taxa, extant and Extinction, extinct amphibians and amniotes, with the latter in turn Evolution, evolving into two major clades, the Sauropsida, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (extinct pelycosaur, "pelycosaurs", therapsids and all extant mammals, including Homo sapiens, humans). Hox gene mutations have resulted in some tetrapods becoming Limbless vertebrate, limbless (snakes, legless lizards, and caecilians) or two-limbed (cetaceans, sirenians, Bipedidae, some lizards, kiwi (bird), kiwis, and the extinct moa and elephant birds). Nevertheless, they still qualify as tetrapods through their ancestry, and some retain a pair of ves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caecilian
Caecilians (; ) are a group of limbless, vermiform (worm-shaped) or serpentine (snake-shaped) amphibians with small or sometimes nonexistent eyes. They mostly live hidden in soil or in streambeds, and this cryptic lifestyle renders caecilians among the least familiar amphibians. Modern caecilians live in the tropics of South America, South and Central America, Africa, and southern Asia. Caecilians feed on small subterranean creatures, such as earthworms. The body is cylindrical and often darkly coloured, and the skull is bullet-shaped and strongly built. Caecilian heads have several unique adaptations, including fused cranial and jaw bones, a two-part system of jaw muscles, and a Chemoreceptor, chemosensory tentacle in front of the eye. The skin is slimy and bears ringlike markings or grooves and may contain scales. Modern caecilians are a clade, the Order (biology), order Gymnophiona (or Apoda ), one of the three living amphibian groups alongside Anura (frogs) and Urodela (sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
