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Alemoatherium
''Alemoatherium'' is an extinct genus of prozostrodontian cynodont which lived in the Late Triassic of Brazil. It contains a single species, ''A. huebneri'', named in 2017 by Agustín Martinelli and colleagues. The genus is based on UFSM 11579b, a left lower jaw (dentary) found in the Alemoa Member of the Santa Maria Formation, preserving the late Carnian-age ''Hyperodapedon'' Assemblage Zone. ''Alemoatherium'' was among the smallest species of cynodonts found in the rich synapsid fauna of the Santa Maria Formation. Its blade-like four-cusped postcanine teeth show many similarities with those of dromatheriids, an obscure group of early prozostrodontians. Description The dentary is similar in shape to that of many other prozostrodontians, with an overall slender form that abruptly changes angle near the front of the jaw. This distinct change in angle separates the dentary into two main regions, the horizontal ramus behind the level of the first postcanine tooth, and the upwards ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santa Maria Formation
The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age (Late Triassic), and is notable for its fossils of cynodonts, "rauisuchian" pseudosuchians, and early dinosaurs and other dinosauromorphs, including the herrerasaurid '' Staurikosaurus'', the basal sauropodomorphs ''Buriolestes'' and '' Saturnalia,'' and the lagerpetid ''Ixalerpeton''. The formation is named after the city of Santa Maria in the central region of Rio Grande do Sul, where outcrops were first studied. The Santa Maria Formation makes up the majority of the Santa Maria Supersequence, which extends through the entire Late Triassic. The Santa Maria Supersequence is divided into four geological sequences, separated from each other by short unconformities. The first two of these sequences (Pinheiros-Chiniquá and Santa Cruz sequences) lie entirely within the Santa Maria Formation, while the third (the Candelária sequence) is shared with the ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prozostrodontia
Prozostrodontia is a clade of cynodonts including mammaliaforms and their closest relatives such as Tritheledontidae and Tritylodontidae. It was erected as a node-based taxon by Liu and Olsen (2010) and defined as the least inclusive clade containing ''Prozostrodon brasiliensis'', '' Tritylodon langaevus'', '' Pachygenelus monus'', and ''Mus musculus'' (the house mouse). Prozostrodontia is diagnosed by several characters, including: * Reduced prefrontal and postorbital bones, with a reduction or disappearance of a strut of bone called the postorbital bar separating the eye socket from the temporal region * Unconnected dentary bones in the lower jaw * The presence of a small hole in the skull called the sphenopalatine foramen * A sagittal crest extending along the top of the skull and connecting with a lambdoidal crest at the back of the skull * Neural spines of the dorsal vertebrae angled backward * A convex-shaped iliac crest and a reduced posterior iliac spine on the hip * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prozostrodontia
Prozostrodontia is a clade of cynodonts including mammaliaforms and their closest relatives such as Tritheledontidae and Tritylodontidae. It was erected as a node-based taxon by Liu and Olsen (2010) and defined as the least inclusive clade containing ''Prozostrodon brasiliensis'', '' Tritylodon langaevus'', '' Pachygenelus monus'', and ''Mus musculus'' (the house mouse). Prozostrodontia is diagnosed by several characters, including: * Reduced prefrontal and postorbital bones, with a reduction or disappearance of a strut of bone called the postorbital bar separating the eye socket from the temporal region * Unconnected dentary bones in the lower jaw * The presence of a small hole in the skull called the sphenopalatine foramen * A sagittal crest extending along the top of the skull and connecting with a lambdoidal crest at the back of the skull * Neural spines of the dorsal vertebrae angled backward * A convex-shaped iliac crest and a reduced posterior iliac spine on the hip * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnian
The Carnian (less commonly, Karnian) is the lowermost stage of the Upper Triassic Series (or earliest age of the Late Triassic Epoch). It lasted from 237 to 227 million years ago (Ma). The Carnian is preceded by the Ladinian and is followed by the Norian. Its boundaries are not characterized by major extinctions or biotic turnovers, but a climatic event (known as the Carnian pluvial episode characterized by substantial rainfall) occurred during the Carnian and seems to be associated with important extinctions or biotic radiations. Stratigraphic definitions The Carnian was named in 1869 by Mojsisovics. It is unclear if it was named after the Carnic Alps or after the Austrian region of Carinthia (''Kärnten'' in German) or after the Carnia historical region in northwestern Italy. The name, however, was first used referring to a part of the Hallstatt Limestone cropping out in Austria. The base of the Carnian Stage is defined as the place in the stratigraphic record where t ... [...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 to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protheriodon
''Protheriodon'' is an extinct genus of probainognathian cynodonts which existed in the Santa Maria Formation of the Paraná Basin in southeastern Brazil during the middle Triassic period. It contains the species ''Protheriodon estudianti''. It was first described by Argentine palaeontologist José Bonaparte José Fernando Bonaparte (14 June 1928 – 18 February 2020) was an Argentine paleontologist who discovered a plethora of South American dinosaurs and mentored a new generation of Argentine paleontologists . One of the best-known Argentine paleo ..., who assigned it to the family Brasilodontidae. More recent studies have however recovered it in a more basal position than other brasilodontids, just outside Prozostrodontia. Cladogram from Martinelli ''et al.'', 2017: References Prehistoric cynodont genera Ladinian genera Middle Triassic synapsids of South America Triassic Brazil Fossils of Brazil Santa Maria Formation Fossil taxa described in 2006 Taxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Probainognathidae
Probainognathidae is an extinct family of insectivorous cynodonts which lived in what is now South America during the Middle to Late Triassic. The family was established by Alfred Romer in 1973 and includes two genera, ''Probainognathus'' from the Chañares Formation of Argentina and ''Bonacynodon'' from the ''Dinodontosaurus'' Assemblage Zone of Brazil. Probainognathids were closely related to the clade Prozostrodontia, which includes mammals and their close relatives. Description Members of Probainognathidae were relatively small-bodied animals, with skull lengths of around . The temporal region (area behind the eye sockets) was rather wide, and longer than the snout. The secondary palate was well-developed compared to earlier cynodonts, and the portion made up by the maxilla was larger than the part made from the palatine bone. The dentary, the tooth-bearing bone of the lower jaw, was quite tall when seen from the side. The mandibular symphysis (the joint between the two h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crown Group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. It is thus a way of defining a clade, a group consisting of a species and all its extant or extinct descendants. For example, Neornithes (birds) can be defined as a crown group, which includes the most recent common ancestor of all modern birds, and all of its extant or extinct descendants. The concept was developed by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms relative to their extinct relatives in his "Die Stammesgeschichte der Insekten", and the "crown" and "stem" group terminology was coined by R. P. S. Jefferies in 1979. Though formulated in the 1970s, the term was not commonly used until its reintroduction in 2000 by Graham Budd and Sören Jensen. Contents of the crown gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prozostrodon
''Prozostrodon'' is an extinct genus of advanced cynodonts that was closely related to the ancestors of mammals. The remains were found in Brazil and are dated middle to late Triassic. It was originally described as a species of ''Thrinaxodon'' and was probably fairly similar to that genus in overall build. The holotype has a skull length of 6.7 cm, indicating the whole animal may have been the size of a cat, though there is some doubt as to whether the find represents an adult individual. The teeth were typical of advanced cynodonts, and the animal was probably a small carnivore hunting reptiles and other small prey. Later analysis indicated ''Prozostrodon'' was more closely related to the mammals than to the ''Thrinaxodon'' species, and it was given its own genus. Cladistic analysis indicates its closest relatives gave rise to the first mammaliaforms and therefore to the crown group mammals. The holotype of ''Prozostrodon'' was found in the Geopark of Paleorrota, Santa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammaliaformes
Mammaliaformes ("mammalian forms") is a clade that contains the crown group mammals and their closest Extinction, extinct relatives; the group adaptive radiation, radiated from earlier probainognathian cynodonts. 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 includes Docodonta and ''Hadrocodium'' as well as the Triassic ''Tikitherium'', the earliest known member of the group. Mammaliaformes is a term of phylogenetic nomenclature. In contrast, the assignment of organisms to 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 fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Root
Dental anatomy is a field of anatomy dedicated to the study of Tooth (human), human tooth structures. The development, appearance, and classification of teeth fall within its purview. (The function of teeth as they contact one another falls elsewhere, under dental occlusion.) Tooth formation begins before birth, and the teeth's eventual Morphology (biology), morphology is dictated during this time. Dental anatomy is also a Taxonomy (general), taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment. Usually, there are 20 primary ("baby") teeth and 32 permanent teeth, the last four being third molars or "wisdom teeth", each of which may or may not grow in. Among primary teeth, 10 usually are found in the maxilla (upper jaw) and the other 10 in the human mandible, mandible (lower jaw). Among permanent teeth, 16 are found in the maxilla and the other 16 in the mandible. Eac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
