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Sinraptorid
Metriacanthosauridae is an extinct family of allosauroid theropod dinosaurs that lived from the Middle Jurassic to the Early Cretaceous. When broken down into its Greek roots, it means "moderately-spined lizards". The family is split into two subgroups: Metriacanthosaurinae, which includes dinosaurs closely related to ''Metriacanthosaurus'', and another group composed of the close relatives of ''Yangchuanosaurus''. Metriacanthosaurids are considered carnosaurs, belonging to the Allosauroidea superfamily. The group includes species of large range in body size. Of their physical traits, most notable are their neural spines.Bailey, Jack Bowman. "Neural Spine Elongation in Dinosaurs: Sailbacks or Buffalo-Backs?" Journal of Paleontology, vol. 71, no. 06, 1997, pp. 1124–1146., doi:10.1017/s0022336000036076. The records of the group are mostly confined to Asia, though ''Metriacanthosaurus'' is known from Europe. Metriacanthosauridae is used as a senior synonym of Sinraptoridae. Diagno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allosauroidea
Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four family (biology), families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were among the apex predators that were active during the Middle Jurassic to Late Cretaceous periods. The most famous and best understood allosauroid is the North American genus ''Allosaurus''. The oldest-known allosauroid, ''Shidaisaurus jinae'', appeared in the early Middle Jurassic about 174 million years ago (Earliest Aalenian stage) of China. The last known definitive surviving members of the group died out around 89 million years ago in Asia (''Shaochilong'') and South America (''Mapusaurus''), though the megaraptorans, which survived until the end of Maastrichtian, may belong to the group as well. A frontal assigned to an allosauroid found to be most closely related to ''Sinraptor'' has also been found in the Coniacian (89-86.3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnosauria
Carnosauria is an extinct large group of predatory dinosaurs that lived during the Jurassic and Cretaceous periods. Starting from the 1990s, scientists have discovered some very large carnosaurs in the carcharodontosaurid family, such as ''Giganotosaurus'', ''Mapusaurus'', ''Carcharodontosaurus'' and ''Tyrannotitan'' which are among the largest known predatory dinosaurs. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin. However, with the description and publication in 2019 of ''Asfaltovenator vialidadi'', a basal allosauroid curiously displaying both primitive and derived features seen in Tetanurae, the new phylogenetic analysis has found Megalosauroidea to be a basal grade of carnosaurs in respect to Allosauroidea; thus significantly expanding Carnosauria's inclusiveness towards its original context. Distinctive characteristics of carnosaurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siamotyrannus
''Siamotyrannus'' (meaning "Siamese tyrant") is a genus of theropod dinosaur from the early Cretaceous of Thailand. Discovery and naming In 1993, Somchai Traimwichanon found a partial skeleton of a large theropod at the Phu Wiang 9 site in Khon Kaen. In 1996, Eric Buffetaut, Varavudh Suteethorn and Haiyan Tong named and described the type species ''Siamotyrannus isanensis''. The generic name is derived from the old Thai kingdom of Siam, and a Latinised Greek ''tyrannus'', meaning "tyrant", in reference to a presumed membership of the Tyrannosauridae. The specific name is derived from Thai ''isan'', "northeastern part", referring to the provenance from northeast Thailand. The holotype, PW9-1, was found in the Sao Khua Formation, dating from the Berriasian-Barremian. It includes the left half of the pelvis, five rear dorsal vertebrae, the sacrum with five sacrals, and thirteen front tail vertebrae. In 1998, a tibia and some individual teeth were referred to the species. Descrip ... [...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] |
Extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squamosal Bone
The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestral component of the dermal roof and is typically thin compared to other skull bones. The squamosal bone lies ventral to the temporal series and otic notch, and is bordered anteriorly by the postorbital. Posteriorly, the squamosal articulates with the quadrate and pterygoid bones. The squamosal is bordered anteroventrally by the jugal and ventrally by the quadratojugal. Function in reptiles In reptiles, the quadrate and articular bones of the skull articulate to form the jaw joint. The squamosal bone lies anterior to the quadrate bone. Anatomy in synapsids Non-mammalian synapsids In non-mammalian synapsids, the jaw is composed of four bony elements and referred to as a quadro-articular jaw because the joint is between the articular an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
Piatnitzkysauridae
Piatnitzkysauridae is an extinct family of megalosauroid or basal Allosauroid dinosaurs. It only consists of three known dinosaur genera: '' Condorraptor'', ''Marshosaurus'', and ''Piatnitzkysaurus.'' The most complete and well known member of this family is ''Piatnitzkysaurus'', which also gives the family its name. Description So far all known piatnitzkysaurids have only been found in Jurassic deposits of the western hemisphere/New world. ''Piatnitzkysaurus'' and ''Condorraptor'' hail from the Cañadón Asfalto Formation of Argentina, which has been dated from the Toarcian epoch of the Early Jurassic to the Bathonian epoch of the Middle Jurassic (approximately 179 to 168 million years ago). ''Marshosaurus'' was found in the Morrison Formation of the United States, which was dated to the Kimmeridgian epoch of the Late Jurassic. Piatnitzkysaurids were among the first large theropods present in South America, and are evidence for a radiation of basal tetanurans in the middle Jur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharodontosauridae
Carcharodontosauridae (carcharodontosaurids; from the Greek καρχαροδοντόσαυρος, ''carcharodontósauros'': "shark-toothed lizards") is a group of carnivorous theropod dinosaurs. In 1931, Ernst Stromer named Carcharodontosauridae as a family, which, in modern paleontology, indicates a clade within Carnosauria. Carcharodontosaurids include some of the largest land predators ever known: ''Giganotosaurus'', ''Mapusaurus'', ''Carcharodontosaurus'', and ''Tyrannotitan'' all rivaled or exceeded ''Tyrannosaurus'' in size. A 2015 paper by Christophe Hendrickx and colleagues gives a maximum length estimate of for the largest carcharodontosaurids, while the smallest carcharodontosaurids were estimated to have been at least long. Evolution Along with the spinosaurids, carcharodontosaurids were the largest predators in the early and middle Cretaceous throughout Gondwana, with species also present in North America (''Acrocanthosaurus''), Europe (''Concavenator'') and Asia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw. Structure In humans, the maxilla consists of: * The body of the maxilla * Four processes ** the zygomatic process ** the frontal process of maxilla ** the alveolar process ** the palatine process * three surfaces – anterior, posterior, medial * the Infraorbital foramen * the maxillary sinus * the incisive foramen Articulations Each maxilla articulates with nine bones: * two of the cranium: the frontal and ethmoid * seven of the face: the nasal, zygomatic, lacrimal, inferior n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
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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