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Muraenosaurus L2
''Muraenosaurus'' (from the Latin "''Muraena''" meaning "eel" and "''Sauros''" meaning lizard) is an extinct genus of cryptoclidid plesiosaur reptile from the Oxford Clay of Southern England. The genus was given its name due to the eel-like appearance of the long neck and small head. ''Muraenosaurus'' grew up to in length and lived roughly between 160 Ma (million years ago) and 164 Ma in the Callovian of the middle Jurassic. Charles E. Leeds collected the first ''Muraenosaurus'' which was then described by H. G. Seeley.Seeley, HG. 1874. On ''Murænosaurus Leedsii'', a Plesiosaurian from the Oxford Clay. Part I. ''Quarterly Journal of the Geological Society'' 30: 197-208. The specimen may have suffered some damage due to the casual style of Charles Leeds’ collection. The first Muraenosaur was recovered with pieces missing from the skull and many of the caudal vertebrae absent. Because the animal was described from Charles Leeds’ collection it was given the name ''Muraenosaur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,British Geological Survey. 2011Stratigraphic framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf: research report RR/11/06 British Geological Survey, Keyworth, Nottingham. the Daohugou Beds in China, the Itat Formation in Russia, and the Isalo III Formation of western Madagascar. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subduction zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracic Vertebrae
In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae and they are intermediate in size between the cervical and lumbar vertebrae; they increase in size going towards the lumbar vertebrae, with the lower ones being much larger than the upper. They are distinguished by the presence of Zygapophysial joint, facets on the sides of the bodies for Articulation (anatomy), articulation with the head of rib, heads of the ribs, as well as facets on the transverse processes of all, except the eleventh and twelfth, for articulation with the tubercle (rib), tubercles of the ribs. By convention, the human thoracic vertebrae are numbered T1–T12, with the first one (T1) located closest to the skull and the others going down the spine toward the lumbar region. General characteristics These are the general characteristics of the second throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalves
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptoclidus
''Cryptoclidus'' ( ) is a genus of plesiosaur reptile from the Middle Jurassic Period (geology), period of England, France, and Cuba. Discovery ''Cryptoclidus'' was a plesiosaur whose specimens include adult and juvenile skeletons, and remains which have been found in various degrees of preservation in England, Northern France, Russia, and South America. Its name, meaning "hidden clavicles", refer to its small, practically invisible clavicles buried in its front limb girdle. The type species was initially described as ''Plesiosaurus eurymerus'' by Phillips (1871). The specific name "wide femur" refers to the forelimb, which was mistaken for a hindlimb at the time. Fossils of ''Cryptoclidus'' have been found in the Oxford Clay of Cambridgeshire, England. The dubious species ''Cryptoclidus beaugrandi'' is known from Kimmeridgian-age deposits in Boulogne-sur-Mer, France. ''Cryptoclidus vignalensis'', which is now considered undiagnostic, hails from the Jagua Formation of western ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliosauridae
Pliosauridae is a family of plesiosaurian marine reptiles from the Latest Triassic to the early Late Cretaceous ( Rhaetian to Turonian stages) of Australia, Europe, North America and South America. The family is more inclusive than the archetypal short-necked large headed species that are placed in the subclade Thalassophonea, with basal forms resembling other plesiosaurs with long necks. They became extinct during the early Late Cretaceous and were subsequently replaced by the mosasaurs. It was formally named by Harry G. Seeley in 1874. Relationships Pliosauridae is a stem-based taxon defined in 2010 (and in earlier studies in a similar manner) as "all taxa more closely related to ''Pliosaurus brachydeirus'' than to '' Leptocleidus superstes'', '' Polycotylus latipinnis'' or ''Meyerasaurus victor''". The family Brachauchenidae has been proposed to include pliosauroids which have very short necks and may include ''Brachauchenius'' and ''Kronosaurus''. However, modern cladisti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kimmerosaurus
''Kimmerosaurus'' ("lizard from Kimmeridge") is an extinct genus of plesiosaur from the family Cryptoclididae. ''Kimmerosaurus'' is most closely related to ''Tatenectes''. Discovery There are very few fossil remains of ''Kimmerosaurus'' known. In fact, nothing has been found to show what ''Kimmerosaurus'' may have looked like below the neck, although the atlas and the axis are similar to those of the plesiosaur ''Colymbosaurus''. It is this lack of any post-cranial fossils, and the bone similarities that has led to the belief that ''Kimmerosaurus'' fossils could be the missing head of ''Colymbosaurus'', a similar plesiosaur with no known skull fossils. The first part of the genus name of ''Kimmerosaurus'' comes from the location of the first ''Kimmerosaurus'' fossils, Kimmeridge Clay deposits of Dorset, England (these deposits are also the root word for the Kimmeridgian stage of the Jurassic period). The second part comes from the Greek word ('), "lizard". Description As ''K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrae
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the vertebral column, backbone), and on the other with phylogenetic differences among the vertebrate taxon, taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptoclididae
Cryptoclididae is a family (biology), family of medium-sized plesiosaurs that existed from the Middle Jurassic to the Early Cretaceous. They had long necks, broad and short skulls and densely packed teeth. They fed on small soft-bodied preys such as small fish and crustaceans. The earliest members of the family appeared during the early Bajocian, and they represented the dominant group of long-necked plesiosaurs during the latter half of the Jurassic. Classification In 2010, two supposed late Cretaceous members of the group were reclassified as other kinds of plesiosauroids. ''Kaiwhekea'' was reclassified to Leptocleididae, and ''Aristonectes'' was transferred to Elasmosauridae. Cladogram based on Ketchum and Benson (2010): References External links palaeos.com Cryptoclidids, Jurassic plesiosaurs Cretaceous plesiosaurs Callovian first appearances Late Cretaceous extinctions Prehistoric reptile families {{Jurassic-reptile-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elasmosauridae
Elasmosauridae is an extinct family of plesiosaurs, often called elasmosaurs. They had the longest necks of the plesiosaurs and existed from the Hauterivian to the Maastrichtian stages of the Cretaceous, and represented one of the two groups of plesiosaurs present at the end of the Cretaceous alongside Polycotylidae. Their diet mainly consisted of crustaceans and molluscs. Description The earliest elasmosaurids were mid-sized, about . In the Late Cretaceous, elasmosaurids grew as large as , such as '' Styxosaurus'', ''Albertonectes'', and '' Thalassomedon''. Their necks were the longest of all the plesiosaurs, with anywhere between 32 and 76 (''Albertonectes'') cervical vertebrae. They weighed up to several tons. Classification Early three-family classification Though Cope had originally recognized ''Elasmosaurus'' as a plesiosaur, in an 1869 paper he placed it, with ''Cimoliasaurus'' and ''Crymocetus'', in a new order of sauropterygian reptiles. He named the group Streptos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muraenosaurus
''Muraenosaurus'' (from the Latin "'' Muraena''" meaning "eel" and "''Sauros''" meaning lizard) is an extinct genus of cryptoclidid plesiosaur reptile from the Oxford Clay of Southern England. The genus was given its name due to the eel-like appearance of the long neck and small head. ''Muraenosaurus'' grew up to in length and lived roughly between 160 Ma (million years ago) and 164 Ma in the Callovian of the middle Jurassic. Charles E. Leeds collected the first ''Muraenosaurus'' which was then described by H. G. Seeley.Seeley, HG. 1874. On ''Murænosaurus Leedsii'', a Plesiosaurian from the Oxford Clay. Part I. ''Quarterly Journal of the Geological Society'' 30: 197-208. The specimen may have suffered some damage due to the casual style of Charles Leeds’ collection. The first Muraenosaur was recovered with pieces missing from the skull and many of the caudal vertebrae absent. Because the animal was described from Charles Leeds’ collection it was given the name ''Muraeno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
