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Sphenosuchidae
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 extremel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Litargosuchus
''Litargosuchus'' is a sphenosuchian Crocodylomorpha, crocodylomorph, a Basal (phylogenetics), basal member of the Crocodylomorpha, crocodylomorph clade from the Early Jurassic of South Africa. Its genus name ''Litargosuchus'' is derived from Greek meaning "fast running crocodile" and its species name ''leptorhynchus'' refers to its Gracility, gracile snout. ''Litargosuchus'', along with all of South Africa's Crocodylomorpha, crocodylomorph Taxon, taxa, are confined to the upper Elliot Formation (UEF) in South Africa. History of discovery In 1988 James Kitching found the holotype fossil of ''Litargosuchus'' in a field expedition in Eagles Crag, a farm near Barkly East in the Eastern Cape. The material recovered consisted of a near-complete skull with its mandible and several bones belonging to the postcranial skeleton. At the time, James Kitching, Kitching was the director of the Evolutionary Studies Institute (previously the Bernard Price Institute) of the University of the Witw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Triassic
The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. The corresponding series (stratigraphy), series of rock beds is known as the Upper Triassic. The Late Triassic is divided into the Carnian, Norian and Rhaetian Geologic time scale, Ages. Many of the first dinosaurs evolved during the Late Triassic, including ''Plateosaurus'', ''Coelophysis'', and ''Eoraptor''. The Triassic–Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. Etymology The Triassic was named in 1834 by Friedrich August von Namoh, Friedrich von Alberti, after a succession of three distinct rock layers (Greek meaning 'triad') that are widespread in southern Germany: the lower Buntsandstein (colourful sandstone'')'', t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bathonian
In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age. Stratigraphic definitions The Bathonian Stage takes its name from Bath, a spa town in England built on Jurassic limestone (the Latinized form of the town name is ''Bathonium''). The name was introduced in scientific literature by Belgian geologist d'Omalius d'Halloy in 1843. The original type locality was located near Bath. The French palaeontologist Alcide d'Orbigny was in 1852 the first to define the exact length of the stage. The base of the Bathonian is at the first appearance of ammonite species '' Parkinsonia (Gonolkites) convergens'' in the stratigraphic column. The global reference profile for the base of the Bathonian (a GSSP) was ratified as Ravin du Bès, Bas-Auran area, Alpes de Haute Provence, France in 2009. The top of the Bat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrestrisuchus
''Terrestrisuchus'' is an extinct genus of very small early crocodylomorph that was about long. Fossils have been found in Wales and Southern England and date from near the very end of the Late Triassic during the Rhaetian, and it is known by type and only known species ''T. gracilis''. ''Terrestrisuchus'' was a long-legged, active predator that lived entirely on land, unlike modern crocodilians. It inhabited a chain of tropical, low-lying islands that made up southern Britain, along with similarly small-sized dinosaurs and abundant rhynchocephalians. Numerous fossils of ''Terrestrisuchus'' are known from fissures in limestone karst which made up the islands it lived on, which formed caverns and sinkholes that preserved the remains of ''Terrestrisuchus'' and other island-living reptiles. Description ''Terrestrisuchus'' was a small, slender crocodylomorph with very long legs, quite unlike modern crocodilians. It was initially estimated to have been between long, although this e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudhesperosuchus
''Pseudhesperosuchus'' (meaning "false '' Hesperosuchus''") 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 partial skeleton and skull found in rocks of the Late Triassic ( Norian-age) Los Colorados Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina. History and description ''Pseudhesperosuchus'' is based on PVL 3830. This specimen consists of a skull and lower jaws, most of the vertebral column, the shoulder girdle, and parts of the arms and legs. The genus was named by José Bonaparte in 1969. The type species is ''P. jachaleri''. The skull, though nearly complete, is poorly preserved, and some of its bones and sutures have been misidentified over the years. A 2002 phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Saltoposuchus
''Saltoposuchus'' is an extinct genus of small (1-1.5 m and 10-15 kg), long-tailed crocodylomorph reptile (Sphenosuchia), from the Norian (Late Triassic) of Europe. The name translated means "leaping foot crocodile". It has been proposed that ''Terrestrisuchus gracilis'' and ''Saltoposuchus connectens'' represent different ontogenetic stages of the same genus. ''Saltoposuchus'' was commonly (and incorrectly) referred to in popular literature as the ancestor (or close ancestors) to dinosaurs, however, recent scientific research show that this is not the case. Description and Paleobiology Fossil evidence of Sphenosuchia and early crocodylomorphs lead paleontologists to conclude that ''Saltoposuchus'' is a terrestrial animal. As a monophyletic group of crocodylomorphs, Saltoposuchidae have many key morphological traits shared with most crocodylomorphs. Skull Much like other crocodylomorphs, ''Saltoposuchus'' skulls had a (reduced) antorbital fenestra, an overhanging squa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenosuchus
''Sphenosuchus'' ("wedge crocodile") is an extinct genus of crocodylomorph from the Early Jurassic Elliot Formation of South Africa, discovered and described early in the 20th century. The skull is preserved very well but other than elements of the forelimb and isolated parts of the hind limb, the ''Sphenosuchus'' material is incomplete. It was probably quadrupedal, but may have been a facultative biped. ''Sphenosuchus'' was first thoroughly described in 1972 by the British palaeontologist Alick Walker, in a paper in the journal ''Nature''. Walker suggested, based on detailed (but still preliminary at that time) studies of the skull of ''Sphenosuchus'' and modern birds, that crocodylomorphs and birds might share an immediate common ancestor. Walker recanted his hypothesis in 1985, but restated and elaborated on it (in essence 'de-recanting') in a monograph published in 1990, which provided the most comprehensive description and discussion of ''Sphenosuchus'' yet published. Bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dibothrosuchus
''Dibothrosuchus'' is a genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It is known from several partial skeletons and skulls. These fossils were found in Lower Jurassic (Lower Pliensbachian, circa 186 million years old) rocks of Yunnan, China. ''Dibothrosuchus'' was a small terrestrial crocodylomorph that probably had a keen sense of hearing, and thus was probably a vocal animal like modern crocodilians. History and description ''Dibothrosuchus'' was named in 1965 by D.J. Simmons based on a partial skull and skeleton collected by Father Oehler of Fu Jen Catholic University from mudstones near Huangchiatien. The type species is ''D. elaphros''. Additional remains of this genus were recovered in 1985 by a joint Chinese-US expedition. Fossils of ''Dibothrosuchus'' come from the Zhangjiawa Formation, being originally assigned to the Reds Beds of the Lufeng Formation, thus being geologically young ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coracoid Process
The coracoid process (from Greek κόραξ, raven) is a small hook-like structure on the lateral edge of the superior anterior portion of the scapula (hence: coracoid, or "like a raven's beak"). Pointing laterally forward, it, together with the acromion, serves to stabilize the shoulder joint. It is palpable in the deltopectoral groove between the deltoid and pectoralis major muscles. Structure The coracoid process is a thick curved process attached by a broad base to the upper part of the neck of the scapula; it runs at first upward and medialward; then, becoming smaller, it changes its direction, and projects forward and lateralward. Anatomically it is divided into intervals of: base of coracoid process, angle of coracoid process, shaft and the apex of the coracoid process. The coracoglenoid notch is an indentation localized between the coracoid process and the glenoid. As the coracoid process projects laterally, it house underneath it the subcoracoid space. The ''ascend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carpal Bones
The carpal bones are the eight small bones that make up the wrist (or carpus) that connects the hand to the forearm. The term "carpus" is derived from the Latin carpus and the Greek καρπός (karpós), meaning "wrist". In human anatomy, the main role of the wrist is to facilitate effective positioning of the hand and powerful use of the extensors and flexors of the forearm, and the mobility of individual carpal bones increase the freedom of movements at the wrist.Kingston 2000, pp 126-127 In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers (or toes in quadrupeds), whereas those of the metacarpus do. The corresponding part of the foot is the tarsus. The carpal bones allow the wrist to move and rotate vertically. Structure Bones The eight carpal bones may be conceptually organized as either two transverse rows, or three longitudinal columns. When c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphies
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Clade analysis T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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