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Mammaliaform
Mammaliaformes ("mammalian forms") is a clade of synapsid tetrapods that includes the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts during the Late Triassic. It is defined as the clade originating from the most recent common ancestor of Morganucodonta and the crown group mammals; the latter is the clade originating with the most recent common ancestor of extant Monotremata, Marsupialia and Placentalia. Besides Morganucodonta and the crown group mammals, Mammaliaformes also includes Docodonta and ''Hadrocodium''. Mammaliaformes is a term of phylogenetic nomenclature. In contrast, the assignment of organisms to class (biology), class Mammalia has traditionally been founded on phenotypic trait, traits and, on this basis, Mammalia is slightly more inclusive than Mammaliaformes. In particular, trait-based taxonomy generally includes ''Adelobasileus'' and ''Sinoconodon'' in Mammalia, though they fall outside the Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Docodonta
Docodonta is an Order (biology), order of extinct Mesozoic Mammaliaformes, mammaliaforms (advanced cynodonts closely related to true Crown group, crown-group mammals). They were among the most common mammaliaforms of their time, persisting from the Early Jurassic to the Early Cretaceous across the continent of Laurasia (modern-day North America, Europe, and Asia). They are distinguished from other early mammaliaforms by their relatively complex Molar (tooth), molar teeth. Docodontan teeth have been described as "pseudotribosphenic": a cusp on the inner half of the upper molar grinds into a basin on the front half of the lower molar, like a Mortar and pestle, mortar-and-pestle. This is a case of convergent evolution with the Tribosphenic molar, tribosphenic teeth of therian mammals. There is much uncertainty for how docodontan teeth developed from their simpler ancestors. Their closest relatives may have been certain Triassic "Symmetrodonta, symmetrodonts", namely ''Woutersia'', an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Castorocauda
''Castorocauda'' is an extinct, semi-aquatic, superficially otter-like genus of docodont mammaliaforms with one species, ''C. lutrasimilis''. It is part of the Yanliao Biota, found in the Daohugou Beds of Inner Mongolia, China dating to the Middle to Late Jurassic. It was part of an explosive Middle Jurassic radiation of Mammaliaformes moving into diverse habitats and niches. Its discovery in 2006, along with the discovery of other unusual mammaliaforms, disproves the previous hypothesis of Mammaliaformes remaining evolutionarily stagnant until the extinction of the non-avian dinosaurs at the end of the Mesozoic. Weighing an estimated , ''Castorocauda'' is the largest known Jurassic mammaliaform. It is the earliest known mammaliaform with aquatic adaptations or a fur pelt. It was also adapted for digging, and its teeth are similar to those of seals and Eocene whales, collectively suggesting it behaved similarly to the modern-day platypus and river otters and ate primarily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haramiyida
Haramiyida is a possibly Paraphyly, paraphyletic order of Mammaliaformes, mammaliaform cynodonts or mammals of controversial taxonomic affinites. Their teeth, which are by far the most common remains, resemble those of the multituberculates. However, based on ''Haramiyavia'', the jaw is less derived; and at the level of evolution of earlier basal mammals like ''Morganucodon'' and ''Kuehneotherium'', with a groove for Ossicles, ear ossicles on the dentary. Some authors have placed them in a clade with Multituberculata dubbed Allotheria within Mammalia. Other studies have disputed this and suggested the Haramiyida were not crown group mammals, but were part of an earlier offshoot of Mammaliaformes instead, either closely related or unrelated to Multituberculates. It is also disputed whether the Late Triassic species are closely related to the Jurassic and Cretaceous members belonging to Euharamiyida, Euharamiyida/Eleutherodontida, as some phylogenetic studies recover the two groups a ... [...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] |
Morganucodon
''Morganucodon'' ("Glamorgan tooth") is an early mammaliaform genus that lived from the Late Triassic to the Middle Jurassic. It first appeared about 205 million years ago. Unlike many other early mammaliaforms, ''Morganucodon'' is well represented by abundant and well-preserved (though in the vast majority of cases disarticulated) material. Most of this comes from Glamorgan in Wales (''Morganucodon watsoni''), but fossils have also been found in Yunnan Province in China (''Morganucodon oehleri'') and various parts of Europe and North America. Some closely related animals (''Megazostrodon'') are known from exquisite fossils from South Africa. The name comes from a Latinization of ''Morganuc'', the name for South Glamorgan in the Domesday Book, the county of Wales where it was discovered by Walter Georg Kühne,Walter G. Kühne, "On a Triconodont tooth of a new pattern from a Fissure-filling in South Glamorgan", ''Proceedings of the Zoological Society of London'', volume 119 (1949� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadrocodium
''Hadrocodium wui'' is an extinct mammaliaform that lived during the Sinemurian stage of the Early Jurassic approximately in the Lufeng Formation in what is now the Yunnan province in south-western China (, paleocoordinates ). It is considered as the closest relative of the class Mammalia. The fossil of this mouse-like, paper-clip sized animal was discovered in 1985 but was then interpreted as a juvenile morganucodontid. ''Hadrocodium'' remained undescribed until 2001; since then its large brain and advanced ear structure have greatly influenced the interpretation of the earliest stages of mammalian evolution, as these mammalian characters could previously be traced only to some . ''Hadrocodium'' is known only from a skull long, and its body would have measured long in total and weighed up to , making it one of the smallest Mesozoic mammaliaforms. The specimen is thought to have been that of a mature adult. The name ''Hadrocodium'' alludes to its large cranial cavity, de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bocaconodon
''Bocaconodon'' (meaning "La Boca conical tooth") is an early mammaliaform genus that lived during the Pliensbachian (Early Jurassic) of Mexico. The type and only species, ''Bocaconodon tamaulipensis'' (referring to Tamaulipas, where the holotype was found), was named and described in 2008. It is known from a single specimen, a partial right dentary bone preserving two nearly complete molar teeth and the rear portion of a third molar. The specimen was found at the Huizachal Canyon locality, "a Pliensbachian floodplain siltstone in the La Boca Formation". Description The only known specimen of ''Bocaconodon'' (IGM 6617) is a partial right dentary bone, which preserves most of the last two molar teeth and the rear portion of a third molar. The preserved part of the dentary was quite thin from top to bottom, with the thinnest part being beneath the last molar. Behind the tooth row there was a facet that may have housed the coronoid bone. At the rear end of the dentary, there w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megazostrodon
''Megazostrodon'' is an extinct genus of basal mammaliaforms belonging to the order Morganucodonta. It is approximately 200 million years old.Fur and Fangs: Mammal Origins . Palaeobiology and Biodiversity Research Group, University of Bristol. Two species are known: ''M. rudnerae'' from the Early Jurassic of Lesotho and South Africa, and ''M. chenali'' from the Late Triassic of France. Discovery The type species ''M. rudnerae'' was first discovered in 1966 in the Elliot Formation of Lesotho, southern Africa, by palaeontologist and archaeologist Ione Rudner. It was first described by Alfred W. Crompton, A. W. Crompton and Farish Jenkins, F. A. Jenkins Jr. in 1968. The generic name ''Mega ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shuotheriidae
Shuotheriidae is a small family of Jurassic mammaliaforms whose remains are found in China, Great Britain and possibly Russia. They have been proposed to be close relatives of Australosphenida (which often controversially includes monotremes), together forming the clade Yinotheria. However, some studies suggest shuotheres are closer to therians than to monotremes, or that australosphenidans and therians are more closely related to each other than either are to shuotheres, with a 2024 study suggesting that shuotheriids were closely related to Docodonta Docodonta is an Order (biology), order of extinct Mesozoic Mammaliaformes, mammaliaforms (advanced cynodonts closely related to true Crown group, crown-group mammals). They were among the most common mammaliaforms of their time, persisting from t ... outside of the Mammalia crown group. References Further reading * Zofia Kielan-Jaworowska, Richard L. Cifelli, and Zhe-Xi Luo, ''Mammals from the Age of Dinosaurs: Origins, Evolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three Evolution of mammalian auditory ossicles, middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors Genetic divergence, diverged in the Carboniferous Period over 300 million years ago. Around 6,640 Neontology#Extant taxon, extant species of mammals have been described and divided into 27 Order (biology), orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, Mole (animal), moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the Artiodactyl, even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including Felidae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammalia
A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including cats, dogs, and seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and birds), constitut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allotheria
Allotheria (meaning "other beasts", from the Ancient Greek language, Greek , '–other and , '–wild animal) is an extinct clade of mammals known from the Mesozoic and early Cenozoic. Shared characteristics of the group are the presence of lower Molar (tooth), molariform Tooth (animal), teeth equipped with longitudinal rows of cusps and enlarged incisors. Typically, the canine teeth are also lost. Allotheria includes Multituberculata, Gondwanatheria (which may be part of Multituberculata, as the sister group to Cimolodonta), and probably Haramiyida, (sometimes only including Euharamiyida) although some studies have recovered haramiyidans to be basal mammaliaforms unrelated to multituberculates. Allotherians are often placed as crown group mammals, more closely related to living marsupials and placentals (Theria) than to monotremes or Eutriconodonta, eutriconodonts, though some studies place the entirety of Allotheria outside of crown Mammalia. References Further reading Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
