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Kayentasuchus
''Kayentasuchus'' (meaning "Kayenta Formation crocodile") is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from a single skeleton found in rocks of the Sinemurian-Pliensbachian-age Lower Jurassic Kayenta Formation, northeastern Arizona. History and description ''Kayentasuchus'' is based on UCMP 131830, a fragmentary skeleton. UCMP 131830 was known for many years before its description as the "Kayenta Form". It was found in 1983 by James M. Clark. The location was at Willow Springs, northeast of Flagstaff. The specimen was found in a channel sandstone about halfway up the formation, in the "silty facies". Specimens of the turtle '' Kayentachelys'', the dinosaur ''Scutellosaurus'', and tritylodonts were found in the immediate vicinity a few meters below it. ''Kayentasuchus'' was named in 2002 by Clark and Hans-Dieter Sues. The type species is ''K. walkeri'' in memory of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenosuchia
Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms, a group which includes all living crocodilians. Stratigraphic range The earliest known members of the group (i.e. '' Hesperosuchus'') are early Norian in age, found in the Blue Mesa Member of the Chinle Formation. Only one sphenosuchian is currently known from the Middle Jurassic, ''Junggarsuchus'', from the Junggar Basin (Shishugou Formation) of China during either the Bathonian or the Callovian (~165 Ma) age,Clark, J.M., ''et al.'' (2004A Middle Jurassic 'sphenosuchian' from China and the origin of the crocodylian skull''Nature'' 430:1021-1024. and the Hallopodidae are known from the Late Jurassic of North America. Phylogeny The monophyly of the group is debated, although several synapomorphies characterize the clade, including extreme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kayenta Formation
The Kayenta Formation is a geological formation in the Glen Canyon Group that is spread across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. Traditionally has been suggested as Sinemurian-Pliensbachian, but more recent dating of detrital zircons has yielded a depositional age of 183.7 ± 2.7 Ma, thus a Pliensbachian-Toarcian age is more likely A previous depth work recovered a solid Lower-Middle Pliensbachian age from measurements done in the Tenney Canyon. This rock formation is particularly prominent in southeastern Utah, where it is seen in the main attractions of a number of national parks and monuments. These include Zion National Park, Capitol Reef National Park, the San Rafael Swell, and Canyonlands National Park. The Kayenta Formation frequently appears as a thinner dark broken layer below Navajo Sandstone and above Wingate Sandstone (all three formations are in the same group). Together, these thre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodylomorpha
Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. During Mesozoic and early Cenozoic times, crocodylomorphs were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. The earliest and most primitive crocodylomorphs are represented by " sphenosuchians", a paraphyletic assemblage containing small-bodied forms with elongated limbs that walked upright, which represents the ancestral morphology of Crocodylomorpha. These forms persisted until the end of the Jurassic. During the Jurassic, Crocodylomorphs morphologically diversified into numerous niches, including into the aquatic and marine realms. Evolutionary history When their extinct species and stem group are examined, the crocodylian lineage (clade Pseudosuchia, formerly Crurotarsi) proves to have been a very diverse and adaptive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kayentachelys
''Kayentachelys'' ("Kayenta turtle") is an extinct genus of turtle known only from the "silty facies" of the Lower Jurassic Kayenta Formation in northeastern Arizona on the lands of the Navajo Nation. History of discovery and significance The earliest mention of turtles from the Kayenta Formation in the literature is within the description of the ornithischian dinosaur ''Scutellosaurus'' by Colbert (1981). These first specimens were collected during the 1970s and early 1980s by field parties from the Museum of Northern Arizona (MNA) and the Museum of Comparative Zoology (MCZ) at Harvard University. Specimens from these field excursions were used to establish the taxon ''Kayentachelys'' in 1987, and it is an MNA specimen (MNA V1558) which was designated as the holotype of the taxon. During the early 1980s, addition turtle specimens from the Kayenta Formation were collected by field parties from the University of California Museum of Paleontology (UCMP), which were reported by Cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodyliformes
Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the only pseudosuchians to survive the K-Pg extinction event. In 1988, Michael J. Benton and James M. Clark argued that all traditional names for well-known groups of animals should be restricted to their crown clades, that is, used only for natural groups comprising all living members of any given lineage. This posed a problem for the crocodilians, because the name Crocodylia, while used in various ways by various scientists, had always included not only living crocodilians but many of their extinct ancestors known only from the fossil record.Benton, M.J. and Clark, J.M. (1988). "Archosaur phylogeny and the relationships of the Crocodylia." Pp. 295–338 in Benton, M.J. (ed.), ''The phylogeny and classification of the Tetrapods, volume 1''. Oxford: Cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen(s). Article 67.1 A similar concept is used for suprageneric groups and called a type genus. In botanical nomenclature, these terms have no formal standing under the code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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