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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] |
Hadrocodium Life Restoration
''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, deriv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution Of Mammals
The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian (geology), Pennsylvanian sub-period of the late Carboniferous period. By the mid-Triassic, there were many synapsid species that looked like mammals. The lineage leading to today's mammals split up in the Jurassic; synapsids from this period include ''Dryolestes'', more closely related to extant placentals and marsupials than to monotremes, as well as ''Ambondro mahabo, Ambondro'', more closely related to monotremes. Later on, the eutherian and metatherian lineages separated; the metatherians are the animals more closely related to the marsupials, while the eutherians are those more closely related to the placentals. Since ''Juramaia'', the earliest known eutherian, lived 160 million years ago in the Jurassic, this divergence must have occurred in the same period. After the Cretaceous–Paleogene extinction event wiped out the non-avian dinosaurs (bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammaliaformes
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 Mammalia has traditionally been founded on 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 Mammaliaformes definition. These ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lufeng Formation
The Lufeng Formation (formerly Lower Lufeng Series) is a Lower Jurassic sedimentary rock formation found in Yunnan, China. It has two units: the lower Dull Purplish Beds/Shawan Member are of Hettangian age, and Dark Red Beds/Zhangjia'ao Member are of Sinemurian age.Luo, Z., and X.-C. Wu. 1994. The small tetrapods of the Lower Lufeng Formation, Yunnan, China; pp. 251–270 in N. C. Fraser and H.-D.Sues (eds.), In the Shadow of the Dinosaurs. Cambridge University Press, New York It is known for its fossils of early dinosaurs. The Dull Purplish Beds have yielded the possible therizinosaur '' Eshanosaurus'', the possible theropod '' Lukousaurus'', and the "prosauropods" "Gyposaurus" ''sinensis'', '' Lufengosaurus'', '' Jingshanosaurus'', and '' Yunnanosaurus''. Dinosaurs discovered in the Dark Red Beds include the theropod '' Sinosaurus triassicus'', the "prosauropods" "Gyposaurus", ''Lufengosaurus'', and ''Yunnanosaurus'', indeterminate remains of sauropods, and the early armor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinoconodon
''Sinoconodon'' is an extinct genus of mammaliamorphs that appears in the fossil record of the Lufeng Formation of China in the Sinemurian stage of the Early Jurassic period, about 193 million years ago. While sharing many plesiomorphic traits with other non-mammaliaform cynodonts, it possessed a special, secondarily evolved jaw joint between the dentary and the squamosal bones, which in more derived taxa would replace the primitive tetrapod one between the articular and quadrate bones. The presence of a dentary-squamosal joint is a trait historically used to define mammals. Description This animal had skull of which suggest a presacral body length of and weight about due to the similar parameters to the European hedgehog. ''Sinoconodon'' closely resembled early mammaliaforms like ''Morganucodon'', but it is regarded as more basal, differing substantially from ''Morganucodon'' in its dentition and growth habits. Like most other non-mammalian tetrapods, such as reptiles and a ... [...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] |
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] |
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] |
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] |
Mammals
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traversodontidae
Traversodontidae is an extinct family of herbivorous cynodonts. Traversodonts were primarily Gondwanan, with many species known from Africa and South America. Recently, traversodonts have also been found from Europe and North America. Traversodonts first appeared in the Middle Triassic and diversified in the Late Triassic before going extinct at the end of the epoch. The family Traversodontidae was erected by Friedrich von Huene in 1936 for cynodonts first found in São Pedro do Sul in Paleorrota, Brazil. Description Traversodonts are members of Gomphodontia, a group of herbivorous cynognathian cynodonts. As an adaptation toward eating plants, they have wide postcanine teeth behind large canines. These postcanines are closely spaced with their crowns touching each other. Each is usually wider than it is long and is covered in several cusps. Because of their complexity, postcanine teeth are the primary means of identifying and distinguishing different species of traversodont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kuehneotheriidae
Kuehneotheriidae is an extinct family of mammaliaforms traditionally placed within 'Symmetrodonta', though now generally considered more basal than true symmetrodonts. All members of Kuehneotheriidae which have been found so far are represented only by teeth, but these teeth have features which have led paleontologists to classify kuehneotheriids as very close relatives of the first true mammals. But fossil clades based solely on teeth often lead to difficulties ( Ausktribosphenidae being a good example), and it is not possible to draw significant conclusions about mammalian evolution from Kuehneotheriidae unless some more complete skeletons are found. See also * Evolution of mammals The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian (geology), Pennsylvanian sub-period of the late Carboniferous period. By the mid-Triassic, there were many synaps ... References Mammaliaformes Prehistoric t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
