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Ichthyostegalia
Ichthyostegalia is an obsolete order of early amphibians, representing the earliest landliving vertebrates. The group is thus an evolutionary grade rather than a clade. While the group are recognized as having feet rather than fins, most, if not all, had internal gills in adulthood and lived primarily as shallow water fish and spent minimal time on land. The group evolved from elpistostegalian fish in the late Devonian, or possibly in the middle Devonian. They continued to thrive as denizens of swampland and tidal channels throughout the period. They gave rise to the Temnospondyli and then disappeared during the transition to the Carboniferous. Classification *Ichthyostegalia ** Acanthostegidae ***'' Acanthostega'' ** Crassigyrinidae ***'' Crassigyrinus'' ** Densignathidae ***'' Densignathus'' ** Elginerpetontidae ***'' Elginerpeton'' ***'' Obruchevichthys'' ** Ichthyostegidae ***'' Hynerpeton'' ***'' Ichthyostega'' ** Jakubsonidae ***'' Jakubsonia'' ** Metaxygnathidae * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hynerpeton
''Hynerpeton'' ( ) is an extinct genus of early four-limbed vertebrate that lived in the rivers and ponds of Pennsylvania during the Late Devonian period, around 365 to 363 million years ago. The only known species of ''Hynerpeton'' is ''H. bassetti'', named after the describer's grandfather, city planner Edward Bassett. ''Hynerpeton'' is known for being the first Devonian four-limbed vertebrate discovered in the United States, as well as possibly being one of the first to have lost Fish gill, internal (fish-like) gills. This genus is known from few remains discovered at the Red Hill fossil site in Hyner, Pennsylvania. The most notable fossil is a large endochondral shoulder girdle consisting of the cleithrum, scapula, and coracoid (but not the interclavicle and clavicles), all connected into one shoulder bone. The inner surface of this shoulder bone possesses an array of depressions believed to have been attachment points for a unique set of powerful muscles around the chest. Thi ... [...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] |
Ichthyostega
''Ichthyostega'', from Ancient Greek ἰχθύς (''ikthús''), meaning "fish", and στέγη (''stégē''), meaning "roof", is an Extinction, extinct genus of limbed tetrapodomorpha, tetrapodomorphs from the Devonian, Late Devonian of what is now Greenland. It was among the earliest four-limbed vertebrates ever in the fossil record and was one of the first with weight-bearing adaptations for terrestrial locomotion. ''Ichthyostega'' possessed lungs and limbs that helped it navigate through shallow water in swamps. Although ''Ichthyostega'' is often labelled a 'tetrapod' because of its limbs and fingers, it evolved long before true crown group tetrapods and could more accurately be referred to as a stegocephalian or stem tetrapod. Likewise, while undoubtedly of amphibian build and habit, it is not a true member of the group in the narrow sense, as the first modern amphibians (members of the group Lissamphibia) appeared in the Triassic Period. Until finds of other early stegocephal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyostegidae
''Ichthyostega'', from Ancient Greek ἰχθύς (''ikthús''), meaning "fish", and στέγη (''stégē''), meaning "roof", is an extinct genus of limbed tetrapodomorphs from the Late Devonian of what is now Greenland. It was among the earliest four-limbed vertebrates ever in the fossil record and was one of the first with weight-bearing adaptations for terrestrial locomotion. ''Ichthyostega'' possessed lungs and limbs that helped it navigate through shallow water in swamps. Although ''Ichthyostega'' is often labelled a 'tetrapod' because of its limbs and fingers, it evolved long before true crown group tetrapods and could more accurately be referred to as a stegocephalian or stem tetrapod. Likewise, while undoubtedly of amphibian build and habit, it is not a true member of the group in the narrow sense, as the first modern amphibians (members of the group Lissamphibia) appeared in the Triassic Period. Until finds of other early stegocephalians and closely related fishes in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temnospondyli
Temnospondyli (from Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') or temnospondyls is a diverse ancient order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian and Triassic periods, with fossils being found on every continent. A few species continued into the Jurassic and Early Cretaceous periods, but all had gone extinct by the Late Cretaceous. During about 210 million years of evolutionary history, they adapted to a wide range of habitats, including freshwater, terrestrial, and even coastal marine environments. Their life history is well understood, with fossils known from the larval stage, metamorphosis and maturity. Most temnospondyls were semiaquatic, although some were almost fully terrestrial, returning to the water only to breed. These temnospondyls were some of the first vertebrates fully adapted to life on land. Although temnospondyls are amph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crassigyrinidae
''Crassigyrinus'' (from , 'thick' and , 'tadpole') is an extinct genus of carnivorous stem tetrapod from the Early Carboniferous Clackmannan Group of Scotland and possibly Greer, West Virginia. Discovery The type specimen was originally described as ''Macromerium scoticum'' and lacked a complete skull. With subsequent discoveries, ''Crassigyrinus'' is now known from three skulls, one of which is in articulation with a fairly complete skeleton, and two incomplete lower jaws. ''Crassigyrinus'' grew up to 2 meters in length, coupled with tiny limbs and unusually large jaws. ''Crassigyrinus'' is taxonomically enigmatic, having confused paleontologists for decades with its apparent fish-like and tetrapod features.Chapter on ''Crassigyrinus'' from ''Gaining ground: the origin and evolution of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaxygnathus
''Metaxygnathus'' is an extinct genus of ichthyostegalian found in Late Devonian deposits of New South Wales, Australia. It is known only from a lower jawbone. Previously thought to be a lobe-finned fish Sarcopterygii (; )—sometimes considered synonymous with Crossopterygii ()—is a clade (traditionally a class or subclass) of vertebrate animals which includes a group of bony fish commonly referred to as lobe-finned fish. These vertebrates ar ..., it has now been reassigned to the earliest group of tetrapodomorphs. References *Campbell, K.S.W. and M.W. Bell. 1977. "A primitive amphibian from the Late Devonian of New South Wales." Alcheringa 1: 369–382. External links ''Metaxygnathus denticulatus''at Devonian Times Stegocephali Prehistoric lobe-finned fish genera Late Devonian sarcopterygians Devonian sarcopterygians of Australia Fossil taxa described in 1977 Fauna of New South Wales Famennian genera {{Paleo-tetrapodomorph-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jakubsonia
''Jakubsonia'' is an extinct genus of early tetrapod from the Late Devonian of Russia. The type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ..., ''Jakubsonia livnensis'', was described and named in 2004. References Stegocephali Prehistoric lobe-finned fish genera Late Devonian sarcopterygians Devonian sarcopterygians of Asia Devonian sarcopterygians of Europe Fossil taxa described in 2004 Extinct animals of Russia {{Paleo-tetrapodomorph-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obruchevichthys
''Obruchevichthys'' is an extinct genus of stem-tetrapod from Latvia during the Late Devonian. When the jawbone, the only known fossil of this creature, was uncovered in Latvia, it was mistaken as a lobe-fin fish. However, when it was analyzed, it proved to hold many similarities to '' Elginerpeton'', from Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac .... It was then declared belonging to the earliest group of tetrapods. References External links ''Devonian Times'' article on ''Obruchevichthys gracilis'' Further reading * ''Gaining Ground: The Origin and Early Evolution of Tetrapods'' by Jennifer A. Clack * ''Origins of the Higher Groups of Tetrapods: Controversy and Consensus'' by Hans-Peter Schultze and Linda Trueb * ''Air-Breathing Fishes: Evolution, Diversity, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elginerpeton
''Elginerpeton'' is a genus of stegocephalian ( stem-tetrapod), the fossils of which were recovered from Scat Craig, Morayshire in the UK, from rocks dating to the late Devonian Period (Late Frasnian stage, 375 million years ago). The type species is ''Elginerpeton pancheni''. ''Elginerpeton'' is known from skeletal fragments including a partial shoulder and hip, a femur, tibia (lower hind limb), and jaw fragments. The holotype is a lower jaw fragment estimated at 40 centimeters in total length. The total body is estimated to have measured about 1.5 m (5 ft) in length. Upon its description, ''Elginerpeton'' was allied with ''Obruchevichthys ''Obruchevichthys'' is an extinct genus of stem-tetrapod from Latvia during the Late Devonian. When the jawbone, the only known fossil of this creature, was uncovered in Latvia, it was mistaken as a lobe-fin fish. However, when it was analyze ...'' in the family Elginerpetontidae. A biomechanical analysis of stegocephali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
