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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'' i ... [...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 repor ... [...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] |
Scutellosaurus
''Scutellosaurus'' ( ) is a genus of thyreophoran ornithischian dinosaur that lived approximately 196 million years ago during the early part of the Jurassic Period in what is now Arizona, USA. It is classified in Thyreophora, the armoured dinosaurs; its closest relatives may have been ''Emausaurus'' and ''Scelidosaurus'', another armored dinosaur which was mainly a quadrupedal dinosaur, unlike bipedal ''Scutellosaurus''. It is one of the earliest representatives of the armored dinosaurs and the basalmost form discovered to date. ''Scutellosaurus'' was a small, lightly-built, ground-dwelling, herbivore, that could grow up to an estimated long. Etymology The genus name ''Scutellosaurus'' means "little-shielded lizard", and is derived from the Latin word "scutellum" meaning "little shield", and the Greek word "sauros" (σαύρα) meaning "lizard". The type and only valid species known today is ''Scutellosaurus lawleri''. The specific name honors David Lawler who collected the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tritylodontidae
Tritylodontidae ("three-knob teeth", named after the shape of their cheek teeth) is an extinct family of small to medium-sized, highly specialized mammal-like cynodonts, bearing several mammalian traits like erect limbs, endothermy and details of the skeleton. They were the last-known family of the non- mammaliaform synapsids, persisting into the Early Cretaceous. Most tritylodontids are thought to have been herbivorous, feeding on vegetation, such as stems, leaves, and roots, although at least one may have had a more omnivorous diet. Tritylodontid fossils are found in the Americas, South Africa, and Eurasia—they appear to have had an almost global distribution, including Antarctica. Description The skull of tritylodontids had a high sagittal crest. They retained the primitive condition of the joint between the quadrate bone of the skull and the articular bone of the lower jaw—the retention of the joint is one of the reasons they are technically regarded to not be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans-Dieter Sues
Hans-Dieter Sues (born January 13, 1956) is a German-born American paleontologist who is Senior Scientist and Curator of Vertebrate Paleontology at the National Museum of Natural History of the Smithsonian Institution in Washington, DC. He received his education at Johannes Gutenberg-Universität Mainz (University of Mainz), University of Alberta, and Harvard University (Ph.D., 1984). Before assuming his present position, Sues worked at the Royal Ontario Museum and the University of Toronto and at the Carnegie Museum of Natural History in Pittsburgh. He is interested in the diversity, paleoecology, and evolutionary history of Paleozoic and Mesozoic tetrapods, especially archosaurian reptiles and cynodont therapsids, and the history of biology and paleontology. Sues has discovered numerous new dinosaurs and other extinct terrestrial vertebrates in Paleozoic and Mesozoic continental strata in North America and Europe. He has authored or co-authored over 150 articles and book chapte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.1 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias limestone from S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alick Walker
Alick Donald Walker (26 October 1925 – 4 December 1999) was a British palaeontologist, after whom the ''Alwalkeria'' genus of dinosaur is named. He was born in Skirpenbeck, near York and attended Pocklington School from 1936 to 1943. He began a degree course in engineering at Cambridge, but dropped out in 1944. In 1948 he returned to university after national service, reading Geology at the University of Bristol. On graduation, he join the research group of Professor Stanley Westoll at the University of Newcastle upon Tyne, working on the fossil reptiles of the Late Triassic found in Elgin. He was appointed Lecturer in Geology in 1954, while working on his PhD. The bony remains of the Elgin reptile fossils were poor, sometimes just indentations in rocks. Walker devised a new casting method to capture the anatomical information in these fossils, using PVC; many of the resulting casts are now in the National Museum of Scotland and the Natural History Museum. His early work was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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