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Pachycostasaurus Front
''Pachycostasaurus'' (meaning 'thick-ribbed lizard') is an extinct Pliosauroid from the Oxford Clay formation of Peterborough, England. History and naming The holotype fossil of Pachycostasaurus was discovered by Alan Dawn, an amateur geologist and museum volunteer, in what is now a quarry in Peterborough. The fossil was described in 1997 by Palaeontologists Arthur Cruickshank, David Martill and Leslie Noè, due to its distinct set of features not present in contemporary pliosaurids ''Liopleurodon'' and ''Simolestes.'' Description The type species, ''P. dawni'', is represented by a single near complete specimen (PETMG R338) which was approximately long and weighed . Perhaps the most defining feature of this genus is the large, pachyostic ribs and gastralia described as ‘sausage-like’ in profile. Pachyostosis is known from a number of Pliosaurid genera (for example '' Monquirasaurus''), and is present in modern animals such as Sirenians ( Dugong and Manatees). This ro ... [...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] |
Osteosclerotic
Osteosclerosis is a disorder that is characterized by abnormal hardening of bone and an elevation in bone density. It may predominantly affect the medullary portion and/or cortex of bone. Plain radiographs are a valuable tool for detecting and classifying osteosclerotic disorders. It can manifest in localized or generalized osteosclerosis. Localized osteosclerosis can be caused by Legg–Calvé–Perthes disease, sickle-cell disease and osteoarthritis among others. Osteosclerosis can be classified in accordance with the causative factor into acquired and hereditary. Types Acquired osteosclerosis * Osteogenic bone metastasis caused by carcinoma of prostate and breast * Paget's disease of bone * Myelofibrosis (primary disorder or secondary to intoxication or malignancy) * Osteosclerosing types of chronic osteomyelitis * Hypervitaminosis D * hyperparathyroidism * Schnitzler syndrome * Mastocytosis Skeletal fluorosis * Monoclonal IgM Kappa cryoglobulinemia * Hepatitis C. Here ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allochthonous
River ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts.Angelier, E. 2003. Ecology of Streams and Rivers. Science Publishers, Inc., Enfield. Pp. 215.”Biology Concepts & Connections Sixth Edition”, Campbell, Neil A. (2009), page 2, 3 and G-9. Retrieved 2010-06-14. River ecosystems are part of larger watershed networks or catchments, where smaller headwater streams drain into mid-size streams, which progressively drain into larger river networks. The major zones in river ecosystems are determined by the river bed's gradient or by the velocity of the current. Faster moving turbulent water typically contains greater concentrations of dissolved oxygen, which supports greater biodiversity than the slow-moving water of pools. These distinctions form the basis for the division of rivers into upland and l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bony Fish
Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species. It is the largest class of vertebrates in existence today. The group Osteichthyes is divided into the ray-finned fish ( Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 425 million years old, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes. Osteichthyes can be compared to Euteleostomi. In paleontology the terms are synonymous. In ichthyology the difference is that Euteleostomi presents a cladistic view which includes the terrestrial tet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belemnitida
Belemnitida (or the belemnite) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to the tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy guard. The calcitic guard is the most common belemnite remain. Belemnites, in life, are thought to have had 10 hooked arms and a pair of fins on the guard. The chitinous hooks were usually no bigger than , though a belemnite could have had between 100 and 800 hooks in total, using them to stab and hold onto prey. Belemnites were an important food source for many Mesozoic marine creatures, both the adults and the planktonic juveniles, and likely played an important role in restructuring marine ecosystems after the Triassic–Jurassic extinction event. They may have laid between 100 and 1,000 eggs. Some species may have been adapted to speed and swam in the tur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line (intertidal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-adult
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles can look very different from the adult form, particularly in colour, and may not fill the same niche as the adult form. In many organisms the juvenile has a different name from the adult (see List of animal names). Some organisms reach sexual maturity in a short metamorphosis, such as eclosion in many insects. For others, the transition from juvenile to fully mature is a more prolonged process—puberty in humans and other species, for example. In such cases, juveniles during this transformation are sometimes called subadults. Many invertebrates, on reaching the adult stage, are fully mature and their development and growth stops. Their juveniles are larvae or nymphs. In vertebrates and some invertebrates (e.g. spiders), larval forms (e.g. tadpoles) are usually considered a development stage of their own, and "juvenile" refers to a post-larval stage that is not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles can look very different from the adult form, particularly in colour, and may not fill the same niche as the adult form. In many organisms the juvenile has a different name from the adult (see List of animal names). Some organisms reach sexual maturity in a short metamorphosis, such as eclosion in many insects. For others, the transition from juvenile to fully mature is a more prolonged process—puberty in humans and other species, for example. In such cases, juveniles during this transformation are sometimes called subadults. Many invertebrates, on reaching the adult stage, are fully mature and their development and growth stops. Their juveniles are larvae or nymphs. In vertebrates and some invertebrates (e.g. spiders), larval forms (e.g. tadpoles) are usually considered a development stage of their own, and "juvenile" refers to a post-larval stage that is not full ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachycostasaurus Front
''Pachycostasaurus'' (meaning 'thick-ribbed lizard') is an extinct Pliosauroid from the Oxford Clay formation of Peterborough, England. History and naming The holotype fossil of Pachycostasaurus was discovered by Alan Dawn, an amateur geologist and museum volunteer, in what is now a quarry in Peterborough. The fossil was described in 1997 by Palaeontologists Arthur Cruickshank, David Martill and Leslie Noè, due to its distinct set of features not present in contemporary pliosaurids ''Liopleurodon'' and ''Simolestes.'' Description The type species, ''P. dawni'', is represented by a single near complete specimen (PETMG R338) which was approximately long and weighed . Perhaps the most defining feature of this genus is the large, pachyostic ribs and gastralia described as ‘sausage-like’ in profile. Pachyostosis is known from a number of Pliosaurid genera (for example '' Monquirasaurus''), and is present in modern animals such as Sirenians ( Dugong and Manatees). This ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Posterior (anatomy)
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axis, anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
