|
Poposaurus
''Poposaurus'' ("Popo Agie Formation, Popo Agie reptile") is an extinct genus of pseudosuchian archosaur from the Late Triassic of the southwestern United States. It belongs to the clade Poposauroidea, an unusual group of Triassic pseudosuchians that includes sail-backed, beaked, and aquatic forms. Fossils have been found in Wyoming, Utah, Arizona, and Texas. Except for the skull, most parts of the skeleton are known. The type species, ''P. gracilis'', was described and named by Maurice Goldsmith Mehl in 1915. A second species, ''P. langstoni'', was originally the type species of the genus ''Lythrosuchus''. Since it was first described, ''Poposaurus'' has been variously classified as a dinosaur, a phytosaur, and a "rauisuchian". Like theropod dinosaurs, ''Poposaurus'' was an obligate biped, meaning that it walked on two legs rather than four. However, as a pseudosuchian, it is more closely related to living crocodilians than to dinosaurs. ''Poposaurus'' is thought to have evolved ... [...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 lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Popo Agie Formation
The Popo Agie Formation is a Triassic geologic formation that crops out in western Wyoming, western Colorado, and Utah. It was deposited during the Late Triassic in fluvial (river) and lacustrine (lake) environments that existed across much of what is now the American southwest. Fragmentary fossils of prehistoric reptiles and amphibians, including pseudosuchian reptiles and temnospondyl Temnospondyli (from Greek language, Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order (biology), order of small to giant tetrapods—often considered Labyrinthodontia, primitive amphi ... amphibians, have been discovered in the Popo Agie Formation. Dinosaur remains are also among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607. Paleobiota Amphibians Reptiles Synapsids See also * List ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rauisuchian
"Rauisuchia" is a paraphyletic group of mostly large and carnivorous Triassic archosaurs. Rauisuchians are a category of archosaurs within a larger group called Pseudosuchia, which encompasses all archosaurs more closely related to crocodilians than to birds and other dinosaurs. First named in the 1940s, Rauisuchia was a name exclusive to Triassic archosaurs which were generally large (often ), carnivorous, and quadrupedal with a pillar-erect hip posture, though exceptions exist for all of these traits. Rauisuchians, as a traditional taxonomic group, were considered distinct from other Triassic archosaur groups such as early dinosaurs, phytosaurs (crocodile-like carnivores), aetosaurs (armored herbivores), and crocodylomorphs (lightly-built crocodilian ancestors). However, more recent studies on archosaur evolution have upended this idea based on phylogenetic analyses and cladistics, a modern approach to taxonomy based on clades (nested monophyletic groups of common ancestry). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1915 In Paleontology
Arthropods Newly named insects Archosauromorphs Newly named pseudosuchians Newly named dinosaurs Data courtesy of George Olshevsky's dinosaur genera list. Anapsids Turtles Synapsids Non-mammalian Paleontologists * Death of Eberhard Fraas. References {{portal, Paleontology 1910s in paleontology Paleontology Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fos ... Paleontology 5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudosuchia
Pseudosuchia is one of two major divisions of Archosauria, including living crocodilians and all archosaurs more closely related to crocodilians than to birds. Pseudosuchians are also informally known as "crocodilian-line archosaurs". Prior to 2011, the clade Pseudosuchia was often called Crurotarsi in reference to the crurotarsal ankle found in almost all members of the group, which traditionally included phytosaurs, ornithosuchids, and suchians. However, a major 2011 study of Triassic archosaur relations proposed that phytosaurs were not closely related to other traditional "crurotarsans", at least compared to "bird-line archosaurs" (Avemetatarsalians) such as pterosaurs and dinosaurs. As a result, the possession of a crurotarsal ankle was considered a plesiomorphic ("primitive") feature retained by pseudosuchians. Crurotarsi now refers to a broader group of reptiles including Pseudosuchia, Phytosauria, and Avemetatarsalia. Despite Pseudosuchia meaning "false crocodiles", ... [...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 orig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacrum
The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity, between the two wings of the pelvis. It forms joints with four other bones. The two projections at the sides of the sacrum are called the alae (wings), and articulate with the ilium at the L-shaped sacroiliac joints. The upper part of the sacrum connects with the last lumbar vertebra (L5), and its lower part with the coccyx (tailbone) via the sacral and coccygeal cornua. The sacrum has three different surfaces which are shaped to accommodate surrounding pelvic structures. Overall it is concave (curved upon itself). The base of the sacrum, the broadest and uppermost part, is tilted forward as the sacral promontory internally. The central part is curved outward toward the posterior, allowing greater room for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metatarsal
The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side (the side of the great toe): the first, second, third, fourth, and fifth metatarsal (often depicted with Roman numerals). The metatarsals are analogous to the metacarpal bones of the hand. The lengths of the metatarsal bones in humans are, in descending order, second, third, fourth, fifth, and first. Structure The five metatarsals are dorsal convex long bones consisting of a shaft or body, a base (proximally), and a head ( distally).Platzer 2004, p. 220 The body is prismoid in form, tapers gradually from the tarsal to the phalangeal extremity, and is curved longitudinally, so as to be concave below, slightly convex above. The base or posterior extremity is wedge-shaped, articulating proximally with the tarsal bones, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytosaur
Phytosaurs (Φυτόσαυροι in greek) are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria. Phytosauria and Phytosauridae are often considered to be equivalent groupings containing the same species, but some studies have identified non-phytosaurid phytosaurians. Phytosaurs were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodilians in size, appearance, and lifestyle, as an example of convergence or parallel evolution. The name "phytosaur" means "plant reptile", as the first fossils of phytosaurs were mistakenly thought to belong to plant eaters. The name is misleading because the sharp teeth in phytosaur jaws clearly show that they were predators. For many years, phytosaurs were considered to be the most basal group of Pseudosuchia (crocodile-line archosaurs), meaning that they were thought to be more closely related to the crocodilians than to birds (the other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischium
The ischium () forms the lower and back region of the hip bone (''os coxae''). Situated below the and behind the pubis, it is one of three regions whose fusion creates the coxal bone. The superior portion of this region forms approximately one-third of the |
Tridactyl
In biology, dactyly is the arrangement of digits ( fingers and toes) on the hands, feet, or sometimes wings of a tetrapod animal. It comes from the Greek word δακτυλος (''dáktylos'') = "finger". Sometimes the ending "-dactylia" is used. The derived adjectives end with "-dactyl" or "-dactylous". As a normal feature Pentadactyly Pentadactyly (from Greek "five") is the condition of having five digits on each limb. It is traditionally believed that all living tetrapods are descended from an ancestor with a pentadactyl limb, although many species have now lost or transformed some or all of their digits by the process of evolution. However, this viewpoint was challenged by Stephen Jay Gould in his 1991 essay "Eight (Or Fewer) Little Piggies", where he pointed out polydactyly in early tetrapods and described the specializations of digit reduction. Despite the individual variations listed below, the relationship is to the original five-digit model. In reptiles, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Poposaurus")
