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Amniota
Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates. Amniotes evolved from amphibious stem tetrapod ancestors during the Carboniferous period. Amniota is defined as the smallest crown clade containing humans, the Greek tortoise, and the Nile crocodile. Amniotes are distinguished from the other living tetrapod clade — the non-amniote lissamphibians (frogs/ toads, salamanders/newts and caecilians) — by: the development of three extraembryonic membranes ( amnion for embryonic protection, chorion for gas exchange, and allantois for metabolic waste disposal or storage); thicker and keratinized skin; costal respiration (breathing by expanding/constricting the rib cage); the presence of adrenocortical and chromaffin tissues as a discrete pair of glands near their kidneys; more complex kidneys; the presence of an astragalus for better extremity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauropsida
Sauropsida (Greek language, Greek for "lizard faces") is a clade of amniotes, broadly equivalent to the Class (biology), class Reptile, Reptilia, though typically used in a broader sense to also include extinct stem-group relatives of modern reptiles and birds (which, as theropod dinosaurs, are nested within reptiles as more closely related to crocodilians than to lizards or turtles).Gauthier J.A. (1994): ''The diversification of the amniotes''. In: D.R. Prothero and R.M. Schoch (ed.) Major Features of Vertebrate Evolution: 129–159. Knoxville, Tennessee: The Paleontological Society. The most popular definition states that Sauropsida is the Sister group, sibling taxon to Synapsida, the other clade of amniotes which includes mammals as its only modern representatives. Although early synapsids have historically been referred to as "mammal-like reptiles", all synapsids are more closely related to mammals than to any modern reptile. Sauropsids, on the other hand, include all amniotes m ... [...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] |
Diadectomorpha
Diadectomorpha is a clade of large tetrapods that lived in Euramerica during the Carboniferous and Early Permian periods and in Asia during Late Permian (Wuchiapingian), They have typically been classified as advanced reptiliomorphs (transitional between "amphibians" ''sensu lato'' and amniotes) positioned close to, but outside of the clade Amniota, though some recent research has recovered them as the sister group to the traditional Synapsida within Amniota, based on inner ear anatomy and cladistic analyses. They include both large (up to 2 meters long) carnivorous and even larger (to 3 meters) herbivorous forms, some semi-aquatic and others fully terrestrial. The diadectomorphs seem to have originated during late Mississippian times, although they only became common after the Carboniferous rainforest collapse and flourished during the Late Pennsylvanian and Early Permian periods. Anatomy Diadectomorphs possessed both amphibian-like and amniote-like characteristics. Origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapsid
Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant reptiles and therefore, birds). Unlike other amniotes, synapsids have a single temporal fenestra, an opening low in the skull roof behind each eye socket, leaving a zygomatic arch, bony arch beneath each; this accounts for the name "synapsid". The distinctive temporal fenestra developed about 318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals. The basal (phylogenetics), basal amniotes (reptiliomorphs) from which synapsids evolved were historically simply called "reptiles". Therefore, stem group synapsids were then described as mammal-like reptiles in classical systematics, and non-therapsid synapsids were also referred to as pelyco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapsida
Synapsida is a diverse group of tetrapod vertebrates that includes all mammals and their extinct relatives. It is one of the two major clades of the group Amniota, the other being the more diverse group Sauropsida (which includes all extant reptiles and therefore, birds). Unlike other amniotes, synapsids have a single temporal fenestra, an opening low in the skull roof behind each eye socket, leaving a bony arch beneath each; this accounts for the name "synapsid". The distinctive temporal fenestra developed about 318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals. The basal amniotes ( reptiliomorphs) from which synapsids evolved were historically simply called "reptiles". Therefore, stem group synapsids were then described as mammal-like reptiles in classical systematics, and non- therapsid synapsids were also referred to as pelycosaurs or pelycosaur- grade syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Captorhinidae
Captorhinidae is an extinct family of tetrapods, traditionally considered primitive Reptile, reptiles, known from the late Carboniferous to the Late Permian. They had a cosmopolitan distribution across Pangea. Description Captorhinids are a clade of small to very large lizard-like animals that date from the Late Carboniferous through the Permian. Their skulls were much stronger than those of their relatives, the protorothyridids, and had teeth that were better able to deal with tough plant material. The postcranial skeleton is similar to those of seymouriamorphs and diadectomorphs; these animals were grouped together with the captorhinids in the order Cotylosauria as the first reptiles in the early 20th century, but are now usually regarded as Stem group, stem-amniotes no closer to reptiles than to mammals. Captorhinids have broad, robust skulls that are generally triangular in shape when seen in dorsal view. The premaxillae are characteristically downturned. The largest captorh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kraterokheirodon
''Kraterokheirodon'' ("cupped hand tooth") is an extinct genus of enigmatic tetrapod, that was possibly an amniote, from the Late Triassic Chinle Formation of Arizona. The type and only species is ''K. colberti''. Although it is known only from two large teeth, their shape is so unlike those of any other animal that ''Kraterokheirodon'' cannot definitively be classified under any known group of tetrapods. Its discovery also indicates that our understanding of Late Triassic tetrapod diversity is still incomplete, with ''Kraterokheirodon'' representing an otherwise unknown lineage of large tetrapod in western North America. Description The teeth of ''Kraterokheirodon'' are broad and relatively large—27.7 mm across at their base and approximately 19 mm high—with an arched ridge across its crown. Without associated jaws, even the orientation of the teeth are unknown, but the ridge has been interpreted as running transversely across the tooth from side-to-side, rather th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edaphosaurus
''Edaphosaurus'' (, meaning "pavement lizard" for dense clusters of its teeth) is a genus of extinct edaphosaurid synapsids that lived in what is now North America and Europe around 303.4 to 272.5 million years ago, during the Late Carboniferous to Early Permian. The American paleontologist Edward Drinker Cope first described ''Edaphosaurus'' in 1882, naming it for the "dental pavement" on both the upper and lower jaws, from the Greek ' ("ground"; also "pavement") and (') ("lizard"). ''Edaphosaurus'' is important as one of the earliest-known, large, plant-eating ( herbivorous), amniote tetrapods (four-legged land-living vertebrates). In addition to the large tooth plates in its jaws, the most characteristic feature of ''Edaphosaurus'' is a sail on its back. A number of other synapsids from the same time period also have tall dorsal sails, most famously the large apex predator ''Dimetrodon''. However, the sail on ''Edaphosaurus'' is different in shape and morphology. The firs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanopidae
Varanopidae is an extinct family (biology), family of amniotes known from the Late Carboniferous to Middle Permian that resembled monitor lizards (with the name of the group deriving from the monitor lizard genus ''Varanus'') and may have filled a similar niche. Typically, they are considered to be relatively Basal (phylogenetics), basal Synapsida, synapsids (and thus more closely related to mammals than to reptiles), although some studies from the late 2010s recovered them being taxonomically closer to diapsid reptiles, recent studies from the early 2020s support their traditional placement as synapsids on the basis of high degree of bone labyrinth ossification, maxillary canal morphology and phylogenetic analyses. A varanopid from the late Middle Permian Pristerognathus Assemblage Zone, ''Pristerognathus'' Assemblage Zone (Capitanian) is the youngest known varanopid and the last member of the "pelycosaur" group of synapsids. Thus, Varanopidae vanishes from the fossil record at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Araeoscelidia
Araeoscelidia or Araeoscelida is a clade of extinct tetrapods (traditionally classified as diapsid reptiles) superficially resembling lizards, extending from the Late Carboniferous to the Early Permian. The group contains the genera '' Araeoscelis'', ''Petrolacosaurus'', the possibly aquatic '' Spinoaequalis'', and less well-known genera such as ''Kadaliosaurus'' and '' Zarcasaurus''. This clade is usually considered to be the sister group to all (currently known) later diapsids. Description Araeoscelidians were small animals (less than one meter in length) looking somewhat like lizards, though they are only distantly related to true lizards. They differ from other, earlier sauropsids by their slender limbs, their elongated tail, and of course by the presence of two temporal openings, the feature defining the diapsid condition. In '' Araeoscelis'', only the upper temporal opening remains, thus resulting in a derived euryapsid condition. Genera Araeoscelidia includes well-know ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incertae Sedis
or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty at specific taxonomic levels is indicated by (of uncertain family), (of uncertain suborder), (of uncertain order) and similar terms. Examples * The fossil plant ''Paradinandra, Paradinandra suecica'' could not be assigned to any family, but was placed ''incertae sedis'' within the order Ericales when described in 2001. * The fossil ''Gluteus minimus (fossil), Gluteus minimus'', described in 1975, could not be assigned to any known animal phylum. The genus is therefore ''incertae sedis'' within the kingdom Animalia. * While it was unclear to which order the New World vultures (family Cathartidae) should be assigned, they were placed in Aves ''incertae sedis''. It was later agreed to place them in a separate order, Cathartiformes. * Boc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casineria
''Casineria'' is an extinct genus of tetrapodomorph which lived about 340–334 million years ago in the Mississippian (geologic period), Mississippian epoch of the Carboniferous period. Its Generic name (biology), generic name, ''Casineria'', is a latinization of Cheese Bay, the site near Edinburgh, Scotland, where the holotype fossil was found. When originally described in 1999, it was identified as a transitional fossil noted for its mix of basal (amphibian-like) and advanced (reptile-like) characteristics, putting it at or very near the origin of the amniotes, the group containing all Mammal, mammals, Bird, birds, modern reptiles, and other descendants of their reptile-like Most recent common ancestor, common ancestor. However, the sole known fossil is lacking key elements such as a skull, making exact analysis difficult. As a result, the classification of ''Casineria'' has been more controversial in analyses conducted since 1999. Other proposed affinities include a placement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
