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Xilousuchus
''Xilousuchus'' is an extinct genus of poposauroid from lower Triassic (Olenekian stage) deposits of Fugu County of northeastern Shanxi Province, China. It is known from the holotype, IVPP V 6026, a single well-preserved partial skeleton including the skull. It was found from the Heshanggou Formation of the Ordos Basin, Hazhen commune. It was first named by Xiao-Chun Wu in 1981 and the type species is ''Xilousuchus sapingensis''. Wu (1981) referred ''Xilousuchus'' to the Proterosuchia. Gower and Sennikov (1996) found it to be an erythrosuchian based strictly on the braincase. A more detailed re-description of the genus was provided by Nesbitt ''et al.'' (2010) and found poposauroid affinities. In his massive revision of archosaurs which included a large cladistic analysis, Sterling J. Nesbitt (2011) found ''Xilousuchus'' to be a poposauroid which is most closely related to ''Arizonasaurus''. ''Xilousuchus'' is the oldest archosaur to date, although ''Ctenosauriscus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poposauroidea
Poposauroidea is a clade of advanced pseudosuchians (archosaurs closer to crocodilians than to dinosaurs). It includes poposaurids, shuvosaurids, ctenosauriscids, and other unusual pseudosuchians such as ''Qianosuchus'' and ''Lotosaurus''. However, it excludes most large predatory quadrupedal "rauisuchians" such as rauisuchids and "prestosuchids". Those reptiles are now allied with crocodylomorphs (crocodile ancestors) in a clade known as Loricata, which is the sister taxon to the poposauroids in the clade Paracrocodylomorpha. Although it was first formally defined in 2007, the name "Poposauroidea" has been used for many years. The group has been referred to as Poposauridae by some authors, although this name is often used more narrowly to refer to the family that includes ''Poposaurus'' and its close relatives. Poposauroids went extinct at the end of the Triassic period along with other non-crocodylomorph pseudosuchians. However, they were among the most diverse and long-lasting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ctenosauriscus
''Ctenosauriscus'' is an extinct genus of sail-backed poposauroid archosaur from Early Triassic deposits of Lower Saxony in northern Germany. It gives its name to the family Ctenosauriscidae, which includes other sail-backed poposauroids such as ''Arizonasaurus''. Fossils have been found in latest Olenekian deposits around 247.5-247.2 million years old, making it one of the first known archosaurs. History of discovery ''Ctenosauriscus'' is known from the holotype, GZG.V.4191, a single partial preserved postcranial skeleton including partial vertebral column, ribs and girdle. The holotype is composed of four slabs, which were labeled A1, A2, B1, and B2 in a 2011 study. Slabs A1 and B1 form the part and slabs A2 and B2 form the counterpart. The holotype was discovered in early 1871 in the Bremke dell locality, near the county of Göttingen. The holotype was found in a deposit called the Solling-Bausandstein, which is an outcropping of the upper Middle Buntsandstein in the region of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vytshegdosuchus
''Vytshegdosuchus'' is an extinct genus of paracrocodylomorph archosaur known from the Early Triassic (latest Olenekian stage) Yarenskian Gorizont of the Komi Republic of the European section of Russia. It contains a single species, ''Vytshegdosuchus zheshartensis''. ''Vytshegdosuchus'' was named by Andreii Sennikov in 1988. Discovery ''Vytshegdosuchus'' is known from the holotype PIN 3361/134, a right ilium, and possibly from the paratype PIN 3361/127, a partial femur. These specimens were collected from the a fossil assemblage called the ''Parotosuchus'' fauna of the Upper Yarenskian Gorizont, in the Zheshart locality along the Vychegda River in Aikino district of the Komi Republic. A pterygoid and postcranial material from the Gam locality, a cervical vertebra (PIN 3369/139) from another locality and postcrania from the Mezhog locality were also assigned to ''Vytshegdosuchus'' by Sennikov (1999). Nesbitt (2009) argued that the specimens referred to ''Vytshegd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosaur
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian dinosaurs, pterosaurs, and extinct relatives of crocodilians. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants. The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives, and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, possessed these features yet originated pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arizonasaurus
''Arizonasaurus'' was a ctenosauriscid archosaur from the Middle Triassic (243 million years ago). ''Arizonasaurus'' is found in the Middle Triassic Moenkopi Formation of northern Arizona. A fairly complete skeleton was found in 2002 by Sterling Nesbitt. The taxon has a large sailback formed by elongated neural spines of the vertebrae. The type species, ''Arizonasaurus babbitti'', was named by Samuel Paul Welles in 1947. Discovery and naming The type species, ''Arizonasaurus babbitti'', was named by Samuel Paul Welles in 1947 on the basis of a few teeth and a maxilla, labelled as specimen UCMP 36232. A fairly complete skeleton was found in 2002 by Sterling Nesbitt. Description ''Arizonasaurus'' had a sail made of tall neural spines. This sail was similar to those of other basal archosaurs, such as other ctenosauriscids like ''Ctenosauriscus'', ''Lotosaurus'', ''Bromsgroveia'', and ''Hypselorhachis''. ''Arizonasaurus'' is described from two braincase specimens. Some ancestral f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Triassic
The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a unit in chronostratigraphy. The Early Triassic is the oldest epoch of the Mesozoic Era. It is preceded by the Lopingian Epoch (late Permian, Paleozoic Era) and followed by the Middle Triassic Epoch. The Early Triassic is divided into the Induan and Olenekian ages. The Induan is subdivided into the Griesbachian and Dienerian subages and the Olenekian is subdivided into the Smithian and Spathian subages. The Lower Triassic series is coeval with the Scythian Stage, which is today not included in the official timescales but can be found in older literature. In Europe, most of the Lower Triassic is composed of Buntsandstein, a lithostratigraphic unit of continental red beds. The Early Triassic and partly also the Middle Triassic span the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythrosuchidae
Erythrosuchidae (meaning "red crocodiles" in Greek) are a family of large basal archosauriform carnivores that lived from the later Early Triassic (Olenekian) to the early Middle Triassic (Anisian). Naming The family Erythrosuchidae was named by David Meredith Seares Watson in 1917.D.M.S. Watson. 1917. "A sketch classification of the Pre-Jurassic tetrapod vertebrates". ''Proceedings of the Zoological Society of London'' 1917: 167–186 Description They were the apex predators of their day, with lengths of to almost . Their fossil remains are known to date from South Africa (Beaufort Group of the Karoo Basin), China, India and European Russia, from the Early to Middle Triassic. Erythrosuchids were unusually large and robust archosauromorphs. Several features set them apart from other archosauriformes and are also seen in later, more derived archosaurs. For example, they lack teeth on the palate, which are found in other early archosauriformes, such as ''Doswellia'' and eupar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cervical Vertebrae
In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid species, the cervical vertebrae bear cervical ribs. In lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The vertebral transverse processes of mammals are homologous to the cervical ribs of other amniotes. Most mammals have seven cervical vertebrae, with the only three known exceptions being the manatee with six, the two-toed sloth with five or six, and the three-toed sloth with nine. In humans, cervical vertebrae are the smallest of the true vertebrae and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process, through which the vertebral artery, vertebral veins, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neural Spine Sail
A neural spine sail is a large, flattish protrusion from the back of an animal formed of a sequence of extended vertebral spinous processes and associated tissues. Such structures are comparatively rare in modern animals, but have been identified in many extinct species of amphibians and amniotes. Paleontologists have proposed a number of ways in which the sail could have functioned in life. Function Varying suggestions have been made for the function of the sail. Thermoregulation The structure may have been used for thermoregulation. The base of the spines have a channel which may have contained a blood vessel supplying abundant blood to the sail. The animal could have used the sail's large surface area to absorb heat from the sun in the morning. As ectotherms they required heat from an external source before their muscles would start to function properly. A predator would thus have an advantage over its slower moving prey. The sail could be used in reverse if the animal wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracrocodylomorpha
Paracrocodylomorpha is a clade of pseudosuchian archosaurs. The clade includes the diverse and unusual group Poposauroidea as well as the generally carnivorous and quadrupedal members of Loricata, including modern crocodylians. Paracrocodylomorpha was named by paleontologist J. Michael Parrish in 1993, although the group is now considered to encompass more reptiles than his original definition intended. The most recent definition of Paracrocodylomorpha, as defined by Sterling Nesbitt in 2011, is "the least inclusive clade containing ''Poposaurus'' and ''Crocodylus niloticus'' (the Nile crocodile). Most groups of paracrocodylomorphs became extinct at the end of the Triassic period, with the exception of the crocodylomorphs, from which crocodylians such as crocodiles and alligators evolved in the latter part of the Mesozoic. History and definition Parrish (1993) defined Paracrocodylomorpha as the last common ancestor of "Poposauridae" and Crocodylomorpha and all of its descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aetosaur
Aetosaurs () are heavily armored reptiles belonging to the extinct order Aetosauria (; from Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized omnivorous or herbivorous pseudosuchians, part of the branch of archosaurs more closely related to crocodilians than to birds and other dinosaurs. All known aetosaurs are restricted to the Late Triassic, and in some strata from this time they are among the most abundant fossil vertebrates. They have small heads, upturned snouts, erect limbs, and a body ornamented with four rows of plate-like osteoderms (bony scutes). Aetosaur fossil remains are known from Europe, North and South America, parts of Africa, and India. Since their armoured plates are often preserved and are abundant in certain localities, aetosaurs serve as important Late Triassic tetrapod index fossils. Many aetosaurs had wide geographic ranges, but their stratigraphic ranges were relatively short. Therefore, the presence of particular aetosaurs can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithosuchidae
Ornithosuchidae is an extinct family of pseudosuchian archosaurs (distant relatives of modern crocodilians) from the Triassic period. Ornithosuchids were quadrupedal and facultatively bipedal (e.g. like chimpanzees), meaning that they had the ability to walk on two legs for short periods of time. They had distinctive, downturned snouts, unique, "crocodile-reversed" ankle bones, and several other features that distinguish them from other archosaurs. Ornithosuchids were geographically widespread during the Carnian and Norian stages of the Late Triassic with members known from Argentina, Brazil, and the United Kingdom. Four genera, comprising ''Ornithosuchus'', ''Venaticosuchus, Dynamosuchus,'' and ''Riojasuchus'' are presently known. The family was first erected by German paleontologist Friedrich von Huene in 1908. Description Skull Ornithosuchids can be identified by the presence of an arched diastema, a gap between the teeth at the front of the snout. When the jaw is closed, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
