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Pachygenelus
''Pachygenelus'' is a genus of extinct cynodont. Fossils have been found from the Karoo basin in South Africa and date back to the Early Jurassic. The genus was named in 1913 on the basis of a partial lower jaw found from South Africa, with the type species being named ''P. monus''. A new species, ''P. milleri'', was named in 1983 and distinguished from the type species in possessing an accessory posterior cusp on the lower postcanines. Description ''Pachygenelus'' had both an articular- quadrate and dentary-squamosal jaw joint characteristic of ictidosaurs. Only mammals possess the dentary-squamosal articulation, while all other tetrapods possess the typical arcticular-quadrate articulation. Thus the jaw of ''Pachygenelus'' can be seen as transitional between non-mammalian synapsids and true mammals. Another feature of ''Pachygenelus'' that is shared with mammals is plesiomorphic prismatic enamel, or enamel arranged into strengthened prisms. The upper and lower tooth rows o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riograndia
''Riograndia'' is an extinct genus of prozostrodontian cynodonts from the Late Triassic of Brazil. The type species, type and only species is ''Riograndia guaibensis'', named after the State of Rio Grande do Sul and Guaíba Basin, where it was discovered. Remains have been found in the Caturrita Formation of the geopark of Paleorrota. It was a small non-mammalian cynodont, with several advanced features also present in mammals. Several specimens of ''Riograndia guaibensis'' have been found in the towns of Candelária, Rio Grande do Sul, Candelária and Faxinal do Soturno in the Caturrita Formation. The genus defines the Riograndia Assemblage Zone, ''Riograndia'' Assemblage Zone. Description Holotype (MCN-PV 2264) is an anterior part of a skull, from the tip of snout to the fronto-parietal contact, with complete dentition. The unique feature of ''Riograndia'' are lobed postcanine teeth with approximately equal 5-9 sharp cuspules located along the almost semicircular edge of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prozostrodontidae
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 the disappearance of a strut of bone called the postorbital bar separating the eye socket from the temporal region * Unfused symphysis between the dentary bones in the lower jaw * The presence of a small hole within the eye socket called the sphenopalatine foramen * A long sagittal crest extending to the rearmost part of the 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] |
Probainognathia
Probainognathia is one of the two major subgroups of the clade Eucynodontia, the other being Cynognathia. The earliest forms were carnivorous and insectivorous, though some groups eventually also evolved herbivorous diets. The earliest and most basal probainognathian is the Middle Triassic (Anisian) aged ''Lumkuia'', from South Africa, though probainognathians would not become prominent until the mid Norian stage of the Late Triassic. Three groups survived the Triassic–Jurassic extinction event, extinction at the end of Triassic: Tritheledontidae and Tritylodontidae, which both survived until the Jurassic—the latter even into the Cretaceous (''Montirictus'' and ''Xenocretosuchus'')—and Mammaliaformes, which includes the mammals. Phylogeny Below is a cladogram from Ruta, Botha-Brink, Mitchell and Benton (2013) showing one hypothesis of cynodont relationships: Cladogram from Stefanello ''et al.'' (2023): See also * Evolution of mammals * List of prehistoric mammals Refe ... [...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] |
Pseudotherium
''Pseudotherium'' ("false beast") is an extinct genus of prozostrodontian cynodonts from the Late Triassic of Argentina. It contains one species, ''P. argentinus'', which was first described in 2019 from remains found in the La Peña Member of the Ischigualasto Formation in the Ischigualasto-Villa Unión Basin. Discovery and naming The holotype and only known specimen, PVSJ 882, was discovered in 2006 by Argentine palaeontologist Ricardo N. Martínez during an expedition to the Ischigualasto Formation. It consists of a partial skull lacking the lower jaw, quadrate bones and most of the zygomatic arches and premaxillae. The generic name ''Pseudotherium'' is derived from the Greek words , meaning "false", and , meaning "beast". The specific name ''argentinus'' references the country of Argentina where it was found. Description ''Pseudotherium'' would have been a relatively large cynodont; excluding its missing premaxillae, the holotype skull is in length. Running along the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prozostrodon
''Prozostrodon'' is an extinct genus of probainognathian cynodonts that was closely related to mammals. The remains were found in Brazil and are dated to the Carnian age of the Late Triassic. The holotype has an estimated skull length of , indicating that the whole animal may have been the size of a cat. The teeth were typical of advanced cynodonts, and the animal was probably a carnivore hunting reptiles and other small prey. Discovery and naming ''Prozostrodon brasiliensis'' was originally described as a species of ''Thrinaxodon'' in a 1987 paper by Mário Costa Barberena, Mário C. Barberena, José F. Bonaparte and A. M. Sá Teixeira. The holotype (UFRGS-PV-0248-T) includes a well-preserved skull preserving the front half of the cranium, a mostly complete lower jaw and all of the teeth, but missing most of the braincase, sagittal crest and zygomatic arches. It also preserves multiple postcranial elements, including parts of the vertebral column, ribs, interclavicle, humeri, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecteniniidae
Ecteniniidae is an extinct family of probainognathian cynodonts from the Triassic of South America. They are notable for their large size, as well as for being among the first synapsids with specializations towards cursoriality. Phylogeny 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 ... from Martínez ''et al.'' (2013): References Probainognathia Late Triassic first appearances Late Triassic extinctions Prehistoric therapsid families Triassic animals of South America {{paleo-cynodont-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Probainognathidae
Probainognathidae is an extinct Family (biology), family of insectivorous cynodonts which lived in what is now South America during the Middle Triassic, 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, ''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 bone, dentary, the tooth-bearing bone of the lower jaw, was quite ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumkuia
''Lumkuia'' is an extinct genus of cynodont, fossils of which have been found in the Cynognathus Assemblage Zone of the Beaufort Group in the South African Karoo Basin that date back to the early Middle Triassic. It contains a single species, ''Lumkuia fuzzi'', which was named in 2001 on the basis of the holotype specimen BP/1/2669, which can now be found at the Bernard Price Institute in Johannesburg, South Africa. The genus has been placed in its own family, Lumkuiidae. ''Lumkuia'' is not as common as other cynodonts from the same locality such as '' Diademodon'' and '' Trirachodon''. Discovery and naming The holotype and only known specimen of ''Lumkuia'', BP/1/2669, was found by Paul Reubsamen near the Lumku Mission in the Eastern Cape province, close to the small town of Lady Frere. It was collected from rocks belonging to the subzone B of the ''Cynognathus'' Assemblage Zone. It consists of a well-preserved skull, part of the shoulder girdle (including the left scapu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tritheledon
''Tritheledon'' is an extinct genus of cynodonts that lived during the Lower Jurassic. Fossils were found in the Elliot Formation, South Africa. Like all cynodonts, it had many traits shared by mammals. Tritheledonts were probably insectivores, and nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ... animals.Luo, Z-X, Z Kielan-Jaworowska & RL Cifelli (2002), In quest for a phylogeny of Mesozoic mammals. ''Acta Palaeontol. Pol''. 47: 1-78. References Further reading * R. Broom. 1912. On a new type of cynodont from the Stormberg. Annals of the South African Museum 7:334-336 Tritheledontidae Early Jurassic synapsids of Africa Jurassic South Africa Fossils of South Africa Fossil taxa described in 1912 {{paleo-cynodont-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irajatherium
''Irajatherium'' is an extinct genus of cynodonts, known only of the type species ''Irajatherium hernandezi''.Martinelli et al., 2005 It is named in honor of Irajá Damiani Pinto. Species ''Irajatherium hernandezi'' is a species known only by a humerus, a femur, two jaws and an upper arch incomplete, has the upper canine teeth after pills across and the post-mandibular canines with a more developed central cusp, followed by three smaller ones. It was collected in the Candelária Formation in the municipality of Faxinal do Soturno in the Paraná Basin of southeastern Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population .... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
