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Nundasuchus
''Nundasuchus'' is an extinct genus of crurotarsan, possibly a suchian archosaur related to Paracrocodylomorpha. Remains of this genus are known from the Middle Triassic Manda beds of southwestern Tanzania. It contains a single species, ''Nundasuchus songeaensis'', known from a single partially complete skeleton, including vertebrae, limb elements, osteoderms, and skull fragments. ''Nundasuchus'' lived in what is now Tanzania, Africa around 240 million years ago. Members of this genus were likely carnivores, around 2.7 to 3 meters (9 feet) long, with ziphodont ( steak knife-like) teeth and rows of bony plates (osteoderms) along their back. Phylogenetic analyses consistently place this genus within the group Crurotarsi based on features of the ankle. Most studies also consider it a pseudosuchian, meaning that it was more closely related to modern crocodilians than it was to dinosaurs. However, ''Nundasuchus'' had an upright stance, with legs situated directly underneath the body, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suchia
Suchia is a clade of archosaurs containing the majority of pseudosuchians (crocodilians and their extinct relatives). It was defined as the least inclusive clade containing '' Aetosaurus ferratus'', '' Rauisuchus tiradentes'', '' Prestosuchus chiniquensis'', and ''Crocodylus niloticus'' (the living Nile crocodile) by Nesbitt (2011). Generally the only pseudosuchian group which is omitted from Suchia is the family Ornithosuchidae, although at least one analysis classifies ornithosuchids as close relatives of erpetosuchids (which are usually considered suchians) and aetosaurs (which are suchians by definition of the group). Phytosaurs are also excluded from Suchia, although it is not certain whether they qualify as pseudosuchians in the first place. There is some controversy over which traits, if any, can be used to distinguish suchians from non-suchian archosaurs. Anatomical features which evolve at the base of a group, and can thus be used to characterize the group, are known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manda Beds
The Manda Formation (also known as the Manda Beds) is a Middle Triassic (Anisian?) or possibly Late Triassic (Carnian?) geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Triassic, including some of the earliest dinosauromorph archosaurs. The formation is often considered to be Anisian in age according to general tetrapod biochronology hypotheses and correlations to the ''Cynognathus'' Assemblage Zone of South Africa. However, some recent studies cast doubt to this age, suggesting that parts deposits may actually be younger (Carnian) in age. History of study One of the first to study rocks of the Manda Formation was British geologist G. M. Stockley. In 1932, Stockley explored the geology of the Ruhuhu Basin in Tanzania. He called a series of layers dating from the Late Carboniferous to the Middle Triassic the Songea Series and divided it into eight units labelled K1-K8. Stockley was also the first to describe fossils from these rocks, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sterling Nesbitt
Sterling Nesbitt (born March 25, 1982, in Mesa, Arizona) is an American paleontologist best known for his work on the origin and early evolutionary patterns of archosaurs. He is currently an associate professor at Virginia Tech in the Department of Geosciences. Biography Sterling Nesbitt received his B.A. in integrative biology with a minor in geology from the University of California Berkeley in 2004. He received his PhD from Columbia University in 2009, completing the majority of his research at the American Museum of Natural History in New York City. He subsequently held postdoctoral researcher positions at the University of Texas at Austin, the University of Washington, and the Field Museum. He is currently an associate professor in thDepartment of Geosciencesat Virginia Tech in Blacksburg, Virginia. He is also a research associate/affiliate of the American Museum of Natural History, the Vertebrate Paleontology Lab at The University of Texas at Austin, the Virginia Museum of Nat ... [...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 othe ... [...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] |
Calcaneus
In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. Structure In humans, the calcaneus is the largest of the tarsal bones and the largest bone of the foot. Its long axis is pointed forwards and laterally. The talus bone, calcaneus, and navicular bone are considered the proximal row of tarsal bones. In the calcaneus, several important structures can be distinguished:Platzer (2004), p 216 There is a large calcaneal tuberosity located posteriorly on plantar surface with medial and lateral tubercles on its surface. Besides, there is another peroneal tubecle on its lateral surface. On its lower edge on either side are its lateral and medial processes (serving as the origins of the abductor hallucis and abductor digiti minimi). The Achilles tendon is inserted into a roughened area on its superio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ticinosuchus
''Ticinosuchus'' is an extinct genus of suchian archosaur from the Middle Triassic (Anisian - Ladinian) of Switzerland and Italy. Description One of only a handful of fossil reptiles that have been found in Switzerland, ''Ticinosuchus'' (meaning "Ticino crocodile" due to its origin from the Swiss canton Ticino) was about long, and its whole body, even the belly, was covered in thick, armoured scutes. These scutes were sometimes considered to have been staggered, alternating between several rows. However, some studies refute this claim, instead purporting that the scutes were aligned in neat rows, with a one-to-one assignment of scutes to vertebrae. The structure of the hips shows that its legs were placed under the body almost vertically. Coupled with the development of a calcaneus and a specialized ankle joint, this would have made ''Ticinosuchus'' a fast runner, unlike most earlier reptiles. ''Ticinosuchus'' is thought to be very close to or possible even the same species t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pubis (bone)
In vertebrates, the pubic region ( la, pubis) is the most forward-facing (ventral and anterior) of the three main regions making up the coxal bone. The left and right pubic regions are each made up of three sections, a superior ramus, inferior ramus, and a body. Structure The pubic region is made up of a ''body'', ''superior ramus'', and ''inferior ramus'' (). The left and right coxal bones join at the pubic symphysis. It is covered by a layer of fat, which is covered by the mons pubis. The pubis is the lower limit of the suprapubic region. In the female, the pubic region is anterior to the urethral sponge. Body The body forms the wide, strong, middle and flat part of the pubic region. The bodies of the left and right pubic regions join at the pubic symphysis. The rough upper edge is the pubic crest, ending laterally in the pubic tubercle. This tubercle, found roughly 3 cm from the pubic symphysis, is a distinctive feature on the lower part of the abdominal wall; important ... [...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", th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Femoral Head
The femoral head (femur head or head of the femur) is the highest part of the thigh bone (femur). It is supported by the femoral neck. Structure The head is globular and forms rather more than a hemisphere, is directed upward, medialward, and a little forward, the greater part of its convexity being above and in front. The femoral head's surface is smooth. It is coated with cartilage in the fresh state, except over an ovoid depression, the fovea capitis, which is situated a little below and behind the center of the femoral head, and gives attachment to the ligament of head of femur. The thickest region of the articular cartilage is at the centre of the femoral head, measuring up to 2.8 mm. The diameter of the femoral head is usually larger in men than in women. Fovea capitis The fovea capitis is a small, concave depression within the head of the femur that serves as an attachment point for the ligamentum teres (Saladin). It is slightly ovoid in shape and is oriented "superior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetics
In biology, phylogenetics (; from Greek language, Greek wikt:φυλή, φυλή/wikt:φῦλον, φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, Protein, protein Amino acid, amino acid sequences, or Morphology (biology), morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
