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Triconodon
''Triconodon'' ("three coned tooth") is a genus of extinct mammal from the Early Cretaceous of England and France with two known species: ''T. mordax'' and ''T. averianovi''. First described in 1859 by Richard Owen,R. Owen. 1859. Palaeontology. '' Encyclopedia Britannica, 8th ed.'' 17:91-176 . Wagner/P. Wagner it is the type genus for the order Triconodonta, a group of mammals characterised by their three-cusped (triconodont) molar teeth. Since then, this "simplistic" type of dentition has been understood to be either ancestral for mammals or else to have evolved multiple times, rendering "triconodonts" a paraphyletic or polyphyletic assemblage respectively, but several lineages of "triconodont" mammals do form a natural, monophyletic group, known as Eutriconodonta, of which ''Triconodon'' is indeed part of. ''Triconodon'', therefore, is significant in the understanding of the evolution of mammals by originating the understanding of the "triconodont" grade and eutriconodont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutriconodonta
Eutriconodonta is an order of early mammals. Eutriconodonts existed in Asia, Africa, Europe, North and South America during the Jurassic and the Cretaceous periods. The order was named by Kermack ''et al.'' in 1973 as a replacement name for the paraphyletic Triconodonta. Traditionally seen as the classical Mesozoic small mammalian insectivores, discoveries over the years have shown them to be among the best examples of the diversity of mammals in this time period, including a vast variety of bodyplans, ecological niches and locomotion methods. Classification "Triconodonta" had long been used as the name for an order of early mammals which were close relatives of the ancestors of all present-day mammals, characterized by molar teeth with three main cusps on a crown that were arranged in a row. The group originally included only the family Triconodontidae and taxa that were later assigned to the separate family Amphilestidae, but was later expanded to include other taxa such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triconodontidae
Triconodontidae is an extinct family of small, carnivorous mammals belonging to the order Eutriconodonta, endemic to what would become Asia, Europe, North America and probably also Africa and South America during the Jurassic through Cretaceous periods at least from 190–70.6 mya. Triconodontids can be distinguished from other eutriconodonts by the shape of their molars, which bore three main cusps of roughly equal size. During occlusion, the upper and lower molars interlocked tightly, producing a self-sharpening cutting edge. Historically, the triconodontids were thought to have a different occlusion pattern than other eutriconodonts, with the middle cusp of the lower molar (cusp a) fitting between the middle cusp (cusp A) and the front cusp (cusp B) of the upper molar, as in the basal mammaliaform ''Morganucodon''. However, a 2020 study on ''Priacodon'' suggests that triconodontids occluded their molars in the same manner as other eutriconodonts (so-called "embrasure occlusio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivore
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other soft tissues) whether through hunting or scavenging. Nomenclature Mammal order The technical term for mammals in the order Carnivora is ''carnivoran'', and they are so-named because most member species in the group have a carnivorous diet, but the similarity of the name of the order and the name of the diet causes confusion. Many but not all carnivorans are meat eaters; a few, such as the large and small cats (felidae) are ''obligate'' carnivores (see below). Other classes of carnivore are highly variable. The Ursids, for example: While the Arctic polar bear eats meat almost exclusively (more than 90% of its diet is meat), almost all other bear species are omnivorous, and one species, the giant panda, is nearly exclusively herbivorous. ... [...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 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'', 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 (birds being the only surviving dinosaurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trioracodon
''Trioracodon'' is an extinct genus of Late Jurassic to Early Cretaceous eutriconodont mammal found in North America and the British Isles. It was named in 1928 ''T. bisulcus'' is known from the Morrison Formation, where it is present in stratigraphic zone 5,Foster, J. (2007). "Appendix." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 327-329. and three other species from the Purbeck Group in Dorset.Clemens, W.A., 1963. ate Jurassic mammalian fossils in the Sedgwick Museum, Cambridge Palaeontology, 6(Part 2), pp.373-377. See also * List of prehistoric mammals * Paleobiota of the Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has a wide assortment of Taxon, taxa represented in its fossil record, including dinosaur fossils in North America ... References Eutriconodonts Berriasian life Tithonian life Early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lulworth Formation
The Lulworth Formation is a Formation (geology), geologic formation in England. It dates from the late Tithonian to the mid Berriasian. It is a subunit of the Purbeck Group. In Dorset, it consists of three members, which are in ascending order, the Mupe Member, the Ridgway Member, and the Warbarrow Tout Member. The Mupe Member is typically 11 to 16 m thick and largely consists of marls and micrites with interbeds of calcareous mudstone. The Ridgeway Member is about 3 to 7 m thick and consists of in its western portion carbonaceous muds, marls and micrites, in the east the muds are replaced by micritic limestone. The Warbarrow Tout Member is 17 to 39 m thick and consists of limestone at the base and micrite and mudstone for the rest of the sequence, this member is the primary source of the vertebrate fossils within the formation. Elsewhere the unit is undifferentiated. Vertebrate paleobiota Amphibians Turtles Lepidosaurs Crocodyliformes Dinosaurs Mammals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purbeck Group
The Purbeck Group is an Upper Jurassic to Lower Cretaceous lithostratigraphic group (a sequence of rock strata) in south-east England. The name is derived from the district known as the Isle of Purbeck in Dorset where the strata are exposed in the cliffs west of Swanage. The Purbeck Group is famous for its fossils of reptiles and early mammals. This sequence of rocks has gone by various names in the past including amongst others the Purbeck Beds, Purbeck Formation, Purbeck Limestone Formation and Purbeck Stone. Rocks of this age have in the past been called the Purbeckian stage by European geologists. The Purbeckian corresponds with the Tithonian to Berriasian stages of the internationally used geologic timescale. Outcrops The Purbeck Group outcrops follow the line of the Jurassic outcrop from Dorset, through the Vale of Wardour, Swindon, Garsington, Brill and Aylesbury. In East Sussex, the Purbeck Group outcrops at three locations north and northwest west of Battle, East Suss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berriasian
In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic) and precedes the Valanginian. Stratigraphic definition The Berriasian Stage was introduced in scientific literature by Henri Coquand in 1869. It is named after the village of Berrias in the Ardèche department of France. The largely non-marine English Purbeck Formation is in part of Berriasian age.In fact, the first rocks to be described of this age were the beds of the English Purbeck Formation, named as the Purbeckian by Alexandre Brongniart in 1829 following description by Henry De la Beche, William Buckland, Thomas Webster and William Henry Fitton. The base of the Berriasian, which is also the base of the Cretaceous System, has traditionally been placed at the first ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot Greenhouse and icehouse earth, greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since Cambrian explosion, complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic. The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs, Pterosaur, pterosaurs, Mosasaur, mosasaurs, and Plesiosaur, plesiosaurs. The Mesozoic was a time of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canine (tooth)
In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however, causing them to resemble incisors and leading them to be called ''incisiform''. They developed and are used primarily for firmly holding food in order to tear it apart, and occasionally as weapons. They are often the largest teeth in a mammal's mouth. Individuals of most species that develop them normally have four, two in the upper jaw and two in the lower, separated within each jaw by incisors; humans and dogs are examples. In most species, canines are the anterior-most teeth in the maxillary bone. The four canines in humans are the two maxillary canines and the two mandibular canines. Details There are generally four canine teeth: two in the upper (maxillary) and two in the lower (mandibular) arch. A canine is placed laterally t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Othniel Charles Marsh
Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among his legacies are the discovery or description of dozens of new species and theories on the origins of birds. Born into a modest family, Marsh was able to afford higher education thanks to the generosity of his wealthy uncle George Peabody. After graduating from Yale College in 1860 he travelled the world, studying anatomy, mineralogy and geology. He obtained a teaching position at Yale upon his return. From the 1870s to 1890s, he competed with rival paleontologist Edward Drinker Cope in a period of frenzied Western American expeditions known as the Bone Wars. Marsh's greatest legacy is the collection of Mesozoic reptiles, Cretaceous birds, and Mesozoic and Tertiary mammals that now constitute the backbone of the collections of Yale's Peabo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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