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Diadectes
''Diadectes'' (meaning ''crosswise-biter'') is an extinct genus of large reptiliomorphs or synapsids that lived during the early Permian period ( Artinskian- Kungurian stages of the Cisuralian epoch, between 290 and 272 million years ago). ''Diadectes'' was one of the first herbivorous tetrapods, and also one of the first fully terrestrial vertebrates to attain large size. Description ''Diadectes'' was a heavily built animal, up to long, with a thick-boned skull, heavy vertebrae and ribs, massive limb girdles, and short, robust limbs. The nature of the limbs and vertebrae clearly indicates a terrestrial animal. The rib cage was assumed to be barrel-shaped, but new fossils show the ribs were actually sticking out to the sides. Paleobiology It possesses some characteristics of reptilians and amphibians, combining a reptile-like skeleton with a more primitive, seymouriamorph-like skull. ''Diadectes'' has been classified as belonging to the sister group of the amniotes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diadectes Tenuitecus
''Diadectes'' (meaning ''crosswise-biter'') is an extinct genus of large reptiliomorphs or synapsids that lived during the early Permian period ( Artinskian- Kungurian stages of the Cisuralian epoch, between 290 and 272 million years ago). ''Diadectes'' was one of the first herbivorous tetrapods, and also one of the first fully terrestrial vertebrates to attain large size. Description ''Diadectes'' was a heavily built animal, up to long, with a thick-boned skull, heavy vertebrae and ribs, massive limb girdles, and short, robust limbs. The nature of the limbs and vertebrae clearly indicates a terrestrial animal. The rib cage was assumed to be barrel-shaped, but new fossils show the ribs were actually sticking out to the sides. Paleobiology It possesses some characteristics of reptilians and amphibians, combining a reptile-like skeleton with a more primitive, seymouriamorph-like skull. ''Diadectes'' has been classified as belonging to the sister group of the amniotes. Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artinskian
In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian Epoch or Series. The Artinskian likely lasted between and million years ago (Ma) according to the most recent revision of the International Commission on Stratigraphy (ICS) in 2022. It was preceded by the Sakmarian and followed by the Kungurian. Stratigraphy The Artinskian is named after the small Russian city of Arti (formerly ''Artinsk''), situated in the southern Ural mountains, about 200 km southwest of Yekaterinburg. The stage was introduced into scientific literature by Alexander Karpinsky in 1874. Base of the Artinskian The base of the Artinskian Stage is defined as the first appearance datum (FAD) of the conodont species '' Sweetognathus whitei'' and '' Mesogondolella bisselli''. In order to constrain this age, the ICS subcommission on Permian stratigraphy informally proposed a candidate GSSP in 2002, later followed by a formal proposal i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seymouriamorpha
Seymouriamorpha were a small but widespread group of limbed vertebrates (tetrapods). They have long been considered reptiliomorphs, and most paleontologists may still accept this point of view, but some analyses suggest that seymouriamorphs are stem-tetrapods (not more closely related to Amniota than to Lissamphibia). Many seymouriamorphs were terrestrial or semi-aquatic. However, aquatic larvae bearing external gills and grooves from the lateral line system have been found, making them unquestionably amphibians. The adults were terrestrial. They ranged from lizard-sized creatures (30 centimeters) to crocodile-sized 150 centimeter long animals. They were reptile-like. If seymouriamorphs are reptiliomorphs, they were the distant relatives of amniotes. Seymouriamorphs form into three main groups, Kotlassiidae, Discosauriscidae, and Seymouriidae, a group that includes the best known genus, '' Seymouria''. The last seymouriamorph became extinct by the end of the Permian. Taxo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amniote
Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are distinguished from the other tetrapod clade — the amphibians — by the development of three extraembryonic membranes (amnion for embryoic protection, chorion for gas exchange, and allantois for metabolic waste disposal or storage), thicker and more keratinized skin, and costal respiration (breathing by expanding/constricting the rib cage). All three main features listed above, namely the presence of an amniotic buffer, water-impermeable cutes and a robust respiratory system, are very important for amniotes to live on land as true terrestrial animals – the ability to reproduce in locations away from water bodies, better homeostasis in drier environments, and more efficient air respiration to power terrestrial locomotions, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labyrinthodontia
"Labyrinthodontia" (Greek, 'maze-toothed') is an informal grouping of extinct predatory amphibians which were major components of ecosystems in the late Paleozoic and early Mesozoic eras (about 390 to 150 million years ago). Traditionally considered a subclass of the class Amphibia, modern classification systems recognize that labyrinthodonts are not a formal natural group ( clade) exclusive of other tetrapods. Instead, they consistute an evolutionary grade (a paraphyletic group), ancestral to living tetrapods such as lissamphibians (modern amphibians) and amniotes (reptiles, mammals, and kin). "Labyrinthodont"-grade vertebrates evolved from lobe-finned fishes in the Devonian, though a formal boundary between fish and amphibian is difficult to define at this point in time. "Labyrinthodont" generally refers to extinct four-limbed tetrapods with a large body size and a crocodile-like lifestyle. The name describes the pattern of infolding of the dentin and enamel of the teeth, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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