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Therocephalia
Therocephalia is an extinct clade of therapsids (mammals and their close extinct relatives) from the Permian and Triassic periods. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their teeth, suggest that they were carnivores. Like other non-mammalian synapsids, therocephalians were once described as "mammal-like reptiles". Therocephalia is the group most closely related to the cynodonts, which gave rise to the mammals. Indeed, it had been proposed that therocephalians themselves may have given rise to the cynodonts, and therefore that therocephalians as recognised are paraphyletic in relation to cynodonts and so not a clade. Conventionally, however, Therocephalia is regarded as the sister clade of Cynodontia, together forming the clade Eutheriodontia. The close relationship of Therocephalia to Cynodontia takes evidence in a variety of skeletal features. Most notable is that the skull roof is narrowed between two enlarged ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycosuchidae
Lycosuchidae is a Family (biology), family of therocephalians (an extinct type of therapsids, broader group which modern mammals belong to) known from fossils from what is now the Beaufort Group of South Africa and that lived during the Middle Permian, Middle to Late Permian between roughly 265 to 258 million years ago. It currently includes only two genera each with a single species, ''Lycosuchus'', represented by ''L. vanderrieti'', and ''Simorhinella'', represented by ''S. baini'', both named by paleontologist Robert Broom in 1903 and 1915, respectively (though ''Simorhinella'' was not recognised as a lycosuchid until 2014). Both species are large predators characterised by their size, reduced tooth counts with large, almost "Saber-toothed predator, sabre toothed" canine teeth, and relatively short, broad and low snouts. Lycosuchids were once thought to be defined by having two simultaneously functional pairs of canines, so-called "double canines", instead of a single pair of l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutherocephalia
Eutherocephalia ("true beast head") is an extinct clade of advanced therocephalian therapsids. Eutherocephalians are distinguished from the lycosuchids and scylacosaurids, two early therocephalian families. While lycosuchids and scyalosaurids became extinct by the end of the Permian period, eutherocephalians survived the Permian–Triassic extinction event. The group eventually became extinct in the Middle Triassic. Characteristics The Eutherocephalians evolved several mammal-like traits through convergent evolution with Cynodontia. Among those traits were the loss of palatine teeth and the reduction of the parietal eye. The latter organ is instrumental in thermoregulation among lizards and snakes, indicating both eutherocephalians and cynodonts were evolving toward a more active, homeothermic lifestyle, though the eye never fully disappeared in the eutherocephalians. Classification The clade Eutherocephalia contains the majority of therocephalians, yet the phylogenetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Therapsids
Therapsida is a clade comprising a major group of eupelycosaurian synapsids that includes mammals and their ancestors and close relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more underneath the body, resulting in a more "standing" quadrupedal posture, as opposed to the lower sprawling posture of many reptiles and amphibians. Therapsids evolved from earlier synapsids commonly called "pelycosaurs", specifically within the Sphenacodontia, more than 279.5 million years ago. They replaced the pelycosaurs as the dominant large land animals in the Guadalupian through to the Early Triassic. In the aftermath of the Permian–Triassic extinction event, therapsids declined in relative importance to the rapidly diversifying archosaurian sauropsids (pseudosuchians, dinosaurs and pterosaurs, etc.) during the Middle Triassic. The therapsids include the cynodonts, the group that gave rise to mammals (M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scylacosauria
Scylacosauria is a clade of therocephalian therapsids. It includes the basal family Scylacosauridae and the infraorder Eutherocephalia. Scylacosauridae and Eutherocephalia form this clade to the exclusion of Lycosuchidae, the most basal therocephalian family. Thus, Scylacosauria includes all therocephalians except lycosuchids. Below is a cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ... showing the phylogenetic position of Scylacosauria: References Therocephalia Guadalupian first appearances Middle Triassic extinctions Tetrapod unranked clades {{paleo-Therapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorynychus
''Gorynychus'' is a genus of therocephalian from the mid-Permian from Kotelnich, Russia. The genus contains two species, ''G. masyutinae'' and ''G. sundyrensis''. It was named after the three-headed dragon Zmey Gorynych (Змей Горыныч) from Russian mythology. Description ''G. masyutinae'', only known from its holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ..., was wolf-sized and appears to have represented the largest predator in the Kotelnich fauna. Like many theriodonts, it had strongly developed and prominent canine teeth. Paleoecology The discovery of such a large therocephalian as the apex predator of its environment coupled with the discovery of a smaller gorgonopsid, the smaller and nocturnal '' Nochnitsa'', in the same formation indicates that a fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutheriodontia
Eutheriodontia is a clade of therapsids which appear during the Middle Permian and which includes therocephalians and cynodonts, this latter group including mammals and related forms. With the dicynodonts, they form one of two lineages of therapsids that survived the End-Permian extinction and which diversified again during the Triassic, before the majority of them disappeared before or during the Triassic–Jurassic extinction, except for a lineage of cynodonts that later gave rise to mammals. Classification The clade was named in 1986 by James Allen Hopson and Herbert Richard Barghusen, the name meaning the "true Theriodontia". Within Hopson's system, the Eutheriodontia are the sister group of the Gorgonopsia within the Theriodontia. A close relationship between therocephalians and cynodonts had been recognized for many years. In 2001 the Eutheriodontia were defined as the least inclusive clade including Mammalia and '' Bauria''.James A. Hopson and James W. Kitching, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynodontia
Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extinct ancestors and close relatives (Mammaliaformes), having evolved from advanced probainognathian cynodonts during the Late Triassic. Non-mammalian cynodonts occupied a variety of ecological niches, both as carnivores and as herbivores. Following the emergence of mammals, most other cynodont lines went extinct, with the last known non-mammaliaform cynodont group, the Tritylodontidae, having its youngest records in the Early Cretaceous. Description Early cynodonts have many of the skeletal characteristics of mammals. The teeth were fully differentiated and the braincase bulged at the back of the head. Outside of some crown-group mammals (notably the therians), all cynodonts probably laid eggs. The temporal fenestrae were much larger than thos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynodont
Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extinct ancestors and close relatives (Mammaliaformes), having evolved from advanced probainognathian cynodonts during the Late Triassic. Non-mammalian cynodonts occupied a variety of ecological niches, both as carnivores and as herbivores. Following the emergence of mammals, most other cynodont lines went extinct, with the last known non-mammaliaform cynodont group, the Tritylodontidae, having its youngest records in the Early Cretaceous. Description Early cynodonts have many of the skeletal characteristics of mammals. The teeth were fully differentiated and the braincase bulged at the back of the head. Outside of some Crown group, crown-group mammals (notably the therians), all cynodonts probably laid eggs. The temporal fenestrae#Fenestra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scylacosauridae
Scylacosauridae is an extinct family of therocephalian therapsids. Scylacosaurids lived during the Permian period and were among the most basal therocephalians. The family was named by South African paleontologist Robert Broom in 1903. Scylacosaurids have long snouts and unusual saber-like canine teeth. References External links Scylacosauridaein the Paleobiology Database The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ... Prehistoric therapsid families Guadalupian first appearances Lopingian extinctions {{Paleo-therapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the Perm Governorate, region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the Sauropsida, sauropsids (reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal-like Reptiles
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 synap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
