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Postorbital Bone
The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some vertebrates, the postorbital is fused with the postfrontal to create a postorbitofrontal. Birds have a separate postorbital as an embryo, but the bone fuses with the frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music * The Front (band), an American rock band signed to Columbia Records and active in the 1980s and e ... before it hatches. References * Roemer, A. S. 1956. ''Osteology of the Reptiles''. University of Chicago Press. 772 pp. Skull {{Vertebrate anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duck Postorbital
Duck is the common name for numerous species of waterfowl in the family (biology), family Anatidae. Ducks are generally smaller and shorter-necked than swans and goose, geese, which are members of the same family. Divided among several subfamilies, they are a form taxon; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species), since swans and geese are not considered ducks. Ducks are mostly aquatic birds, and may be found in both fresh water and sea water. Ducks are sometimes confused with several types of unrelated water birds with similar forms, such as loons or divers, grebes, gallinules and coots. Etymology The word ''duck'' comes from Old English 'diver', a derivative of the verb 'to duck, bend down low as if to get under something, or dive', because of the way many species in the dabbling duck group feed by upending; compare with Dutch language, Dutch and German language, German 'to dive'. This word replaced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dromaeosaurus Skull En
''Dromaeosaurus'' (, "running lizard") is a genus of dromaeosaurid theropod dinosaur which lived during the Late Cretaceous period (middle late Campanian and Maastrichtian), sometime between 80 and 69 million years ago, in Alberta, Canada and the western United States. The type species is ''Dromaeosaurus albertensis'', which was described by William Diller Matthew and Barnum Brown in 1922. Its fossils were unearthed in the Dinosaur Park Formation. Teeth attributed to this genus have been found in the Prince Creek Formation. ''Dromaeosaurus'' is the type genus of both Dromaeosauridae and Dromaeosaurinae, which include many genera with similar characteristics to ''Dromaeosaurus'' such as possibly its closest relative ''Dakotaraptor''. ''Dromaeosaurus'' was heavily built, more so than other dromaeosaurs that are similar in size, like ''Velociraptor''. Discovery and naming Despite receiving widespread attention in popular books on dinosaurs, and the usage of a complete mounted skelet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull Roof
The skull roof, or the roofing bones of the skull, are a set of bones covering the brain, eyes and nostrils in bony fishes and all land-living vertebrates. The bones are derived from dermal bone and are part of the dermatocranium. In comparative anatomy the term is used on the full dermatocranium. Romer, A.S. & T.S. Parsons. 1977. ''The Vertebrate Body.'' 5th ed. Saunders, Philadelphia. (6th ed. 1985) In general anatomy, the roofing bones may refer specifically to the bones that form above and alongside the brain and neurocranium (i.e., excluding the marginal upper jaw bones such as the maxilla and premaxilla), and in human anatomy, the skull roof often refers specifically to the skullcap. Origin Early armoured fish did not have a skull in the common understanding of the word, but had an endocranium that was partially open above, topped by dermal bones forming armour. The dermal bones gradually evolved into a fixed unit overlaying the endocranium like a heavy "lid", protec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postfrontal
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium and the viscerocranium (facial skeleton) that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans these sensory structures are part of the facial skeleton. Functions of the skull include protection of the brain, fixing the distance between the eyes to allow stereoscopic vision, and fixing the position of the ears to enable sound localisation of the direction and distance of sounds. In some animals, such as horned ungulates (mammals with hooves), the skull also has a defensive function by providing the mount (on the fronta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Fenestra
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium and the viscerocranium (facial skeleton) that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans these sensory structures are part of the facial skeleton. Functions of the skull include protection of the brain, fixing the distance between the eyes to allow stereoscopic vision, and fixing the position of the ears to enable sound localisation of the direction and distance of sounds. In some animals, such as horned ungulates (mammals with hooves), the skull also has a defensive function by providing the mount (on the frontal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frontal Bone
The frontal bone is a bone in the human skull. The bone consists of two portions.''Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, part of the bony orbital cavity holding the eye, and part of the bony part of the nose respectively. The name comes from the Latin word ''frons'' (meaning " forehead"). Structure of the frontal bone The frontal bone is made up of two main parts. These are the squamous part, and the orbital part. The squamous part marks the vertical, flat, and also the biggest part, and the main region of the forehead. The orbital part is the horizontal and second biggest region of the frontal bone. It enters into the formation of the roofs of the orbital and nasal cavities. Sometimes a third part is included as the nasal part of the frontal bone, and sometimes this is included with the squamous part. The nasal part is between the brow ridges, and ends in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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