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Anningasaura
''Anningasaura'' is an extinct genus of basal plesiosaur. It is known from a single type species, ''A. lymense'', discovered in Early Jurassic rocks of Lyme Regis in the United Kingdom. Discovery ''Anningasaura'' is known only from the holotype specimen NHMUK 49202, which consists of a complete skull, palate, and mandible, with eight associated cervical vertebrae, including the atlas-axis complex. The partial skeleton came from a juvenile plesiosaur. It was originally referred to ''"Plesiosaurus" macrocephalus'' by Charles William Andrews in 1896, which is otherwise known only from the very young type specimen NHMUK OR1336. NHMUK 49202 was collected at Lyme Regis, of Dorset, from the Hettangian to early Sinemurian-aged beds of the Lower Lias Group. Description NHMUK 49202 possesses plesiomorphic characters, including premaxillae that do not separate the frontals on the midline, narrow cranioquadrate passages and the lack of a constricting groove around t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anningasaura
''Anningasaura'' is an extinct genus of basal plesiosaur. It is known from a single type species, ''A. lymense'', discovered in Early Jurassic rocks of Lyme Regis in the United Kingdom. Discovery ''Anningasaura'' is known only from the holotype specimen NHMUK 49202, which consists of a complete skull, palate, and mandible, with eight associated cervical vertebrae, including the atlas-axis complex. The partial skeleton came from a juvenile plesiosaur. It was originally referred to ''"Plesiosaurus" macrocephalus'' by Charles William Andrews in 1896, which is otherwise known only from the very young type specimen NHMUK OR1336. NHMUK 49202 was collected at Lyme Regis, of Dorset, from the Hettangian to early Sinemurian-aged beds of the Lower Lias Group. Description NHMUK 49202 possesses plesiomorphic characters, including premaxillae that do not separate the frontals on the midline, narrow cranioquadrate passages and the lack of a constricting groove around t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2012 In Paleontology
Note: In 2012, the International Code of Zoological Nomenclature was amended, with new regulations allowing the publication of new names and nomenclatural acts in zoology after 2011, in works "produced in an edition containing simultaneously obtainable copies by a method that assures (...) widely accessible electronic copies with fixed content and layout", provided that the work is registered in ZooBank before it is published, the work itself states the date of publication with evidence that registration has occurred, and the ZooBank registration states both the name of an electronic archive intended to preserve the work and the ISSN or ISBN associated with the work. New scientific names appearing in electronic works are not required to be registered in ZooBank, only the works themselves are. Works containing descriptions of some of the taxa listed below were not printed on paper in 2012; however, the taxa that were described in works which were registered in ZooBank in 2012 are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution, and some species at least partly inhabited freshwater environments. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous ''Plesiosaurus'', was named in 1821. Since then, more than a hundred valid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoplesiosauria
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution, and some species at least partly inhabited freshwater environments. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous ''Plesiosaurus'', was named in 1821. Since then, more than a hundred vali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosaurus
''Plesiosaurus'' (Greek: ' ('), near to + ' ('), lizard) is a genus of extinct, large marine sauropterygian reptile that lived during the Early Jurassic. It is known by nearly complete skeletons from the Lias Group, Lias of England. It is distinguishable by its small head, long and slender neck, broad turtle-like body, a short tail, and two pairs of large, elongated paddles. It lends its name to the order Plesiosauria, of which it is an early, but fairly typical member. It contains only one species, the type species, type, ''Plesiosaurus dolichodeirus''. Other species once assigned to this genus, including ''P. brachypterygius'', ''P. guilielmiimperatoris'', and ''P. tournemirensis'' have been reassigned to new genera, such as ''Hydrorion'', ''Seeleyosaurus'' and ''Occitanosaurus''. Discovery The first complete skeleton of ''Plesiosaurus'' was discovered by early paleontologist and fossil hunter Mary Anning in Sinemurian (Early Jurassic)-age rocks of the lower Lias Group in Dec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pistosaurus
''Pistosaurus'' (''pistos'' in Greek meaning 'credible' and ''sauros'' 'lizard') is an extinct genus of aquatic sauropterygian reptile closely related to plesiosaurs. Fossils have been found in France and Germany, and date to the Middle Triassic. It contains a single species, ''Pistosaurus longaevus. Pistosaurus'' is known as the oldest "subaquatic flying" reptile on earth. The skull of ''Pistosaurus'' generally resembles that of other Triassic sauropterygians. However, there are several synapomorphies that make ''Pistosaurus'' distinguished: the long, slender, snout; the possession of splint-like nasals that are excluded from the external naris; and the posterior extension of the premaxilla to the frontals. Based on synapomorphies such as the small nasals size and the presence of interpterygoid vacuity, ''Pistosaurus'' is more closely related to Plesiosauria than to ''Nothosaurus''. ''Pistosaurus'' is often mistaken with ''Nothosaurus'' and Plesiosauria. ''Nothosaurus'' belo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ 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 amino acid sequences, or 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 unrooted tree diagram (a network) makes no assumption about the ancestral line, and does ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pistosauria
Pistosauroidea is a group of marine reptiles within the superorder Sauropterygia that first appeared in the latter part of the Early Triassic and were the ancestors of plesiosaurs. Pistosauroids are rare in Triassic marine assemblages, and are represented by only a few fossils from central Europe, the United States, and China. Recent phylogenetic analyses consider the Triassic pistosauroids to be a paraphyletic grouping, meaning that they do not form a true clade. Plesiosauria is now placed within Pistosauroidea, while the traditional pistosauroids are successively more basal, or primitive, sauropterygians. Below is a cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ... of pistosauroid relationships from Cheng ''et al.'' (2006): Below is a cladogram of pistosauroi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occipital Condyle
The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra. The condyles are oval or reniform (kidney-shaped) in shape, and their anterior extremities, directed forward and medialward, are closer together than their posterior, and encroach on the basilar portion of the bone; the posterior extremities extend back to the level of the middle of the foramen magnum. The articular surfaces of the condyles are convex from before backward and from side to side, and look downward and lateralward. To their margins are attached the capsules of the atlanto-occipital joints, and on the medial side of each is a rough impression or tubercle for the alar ligament. At the base of either condyle the bone is tunnelled by a short canal, the hypoglossal canal. Clinical significance Fracture of an occipital condyle may occur in isolation, or as part of a more extended basilar skull fracture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiomorphic
In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy, all mean a trait shared between species because they share an ancestral species. Apomorphic and synapomorphic characteristics convey much information about evolutionary clades and can be used to define taxa. However, plesiomorphic and symplesiomorphic characteristics cannot. The term ''symplesiomorphy'' was introduced in 1950 by German entomologist Willi Hennig. Examples A backbone is a plesiomorphic trait shared by birds and mammals, and does not help in placing an animal in one or the other of these two clades. Birds and mammals share this trait because both clades are descended from the same far distant ancestor. Other clades, e.g. snakes, lizards, turtles, fish, frogs, all have backbones and none are either birds no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
