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Proceratosaurids
Proceratosauridae is a family or clade of tyrannosauroid theropod dinosaurs from the Middle Jurassic to the Early Cretaceous. Distinguishing features Unlike the advanced tyrannosaurids but similar to primitive tyrannosauroids like '' Dilong'', proceratosaurids were generally small (with the exception of the possible proceratosaurids ''Yutyrannus'' and ''Sinotyrannus'') and had fairly long, three-fingered arms capable of grasping prey. In comparison to other members of Tyrannosauroidea, proceratosaurids can be distinguished by the following features according to phylogenetic analyses by Averianov ''et al''. (2010) and Loewen ''et al''. (2013) : * A sagittal cranial crest formed by the nasals starting at the junction of the premaxilla and nasals. * Extremely elongated external nares, with posterior margins posterior to the anterior margin of the antorbital fossa and maxillary fenestrae. * A short ventral margin of the premaxilla. * The depth of the antorbital fossa ventral to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proceratosaurus Bradleyi
''Proceratosaurus'' ( ) is a genus of theropod dinosaur that lived during the Middle Jurassic in what is now England. The holotype and only known specimen consists of a mostly complete skull with an accompanying lower jaw and a bone, found near Minchinhampton, a town in Gloucestershire. It was originally described as a species of ''Megalosaurus'' in 1910, ''M. bradleyi'', but was moved to its own genus, ''Proceratosaurus'', in 1926. The genus was named for its supposed close relationship with ''Ceratosaurus,'' later shown to be erroneous, due to perceived resemblance of ''Proceratosaurus''' incomplete cranial crest to ''Ceratosaurus nasal horn. A small to medium-sized dinosaur, the skull of ''Proceratosaurus'' is long as preserved, and the dinosaur is estimated to have measured around in length. The skull is characterised by a number of distinguishing features, including a cranial crest that begins at the junction between the and the nasal bone. The teeth are heterodont, ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 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 Calcaire de Caen of France, the Daohugou Beds in China, the Itat Formation in Russia, the Tiouraren Formation of Niger, and the Isalo III Formation of western Madagascar. Rocks of the Middle Jurassic were formerly (until about 1980s) in Europe called ''Dogger'' or ''Brown Jurassic''. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrannosauridae
Tyrannosauridae (or tyrannosaurids, meaning "tyrant lizards") is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to fifteen genera, including the eponymous ''Tyrannosaurus''. The exact number of genera is controversial, with some experts recognizing as few as three. All of these animals lived near the end of the Cretaceous Period and their fossils have been found only in North America and Asia. Although descended from smaller ancestors, tyrannosaurids were almost always the largest predators in their respective ecosystems, putting them at the apex of the food chain. The largest species was ''Tyrannosaurus rex'', the most massive known terrestrial predator, which measured over in length and according to most modern estimates up to in weight. Tyrannosaurids were bipedal carnivores with massive skulls filled with large teeth. Despite their large size, their legs were long and proportioned for fast movement. In contrast, their arms were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compsognathus
''Compsognathus'' (; Ancient Greek, Greek ''kompsos''/κομψός; "elegant", "refined" or "dainty", and ''gnathos''/γνάθος; "jaw") is a genus of small, bipedalism, bipedal, carnivore, carnivorous theropoda, theropod dinosaur. Members of its single species ''Compsognathus longipes'' could grow to around the size of a chicken (bird), chicken. They lived about 150 mya (unit), million years ago, during the Tithonian Stage (stratigraphy), age of the late Jurassic Period (geology), period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany in the 1850s and the second in France more than a century later. Today, ''C. longipes'' is the only recognized species, although the French specimen was once thought to belong to a separate species named ''C. corallestris''. Many presentations still describe ''Compsognathus'' as "chicken-sized" dinosaurs because of the size of the German specimen, which is now believed to be a juvenile. ''Comps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allosaurus
''Allosaurus'' ( ) is an extinct genus of theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic period ( Kimmeridgian to late Tithonian ages). The first fossil remains that could definitively be ascribed to this genus were described in 1877 by Othniel C. Marsh. The name "''Allosaurus''" means "different lizard", alluding to its lightweight , which Marsh believed were unique. The genus has a very complicated taxonomy and includes at least three valid species, the best known of which is ''A. fragilis''. The bulk of ''Allosaurus'' remains come from North America's Morrison Formation, with material also known from the Alcobaça Formation and Lourinhã Formation in Portugal. It was known for over half of the 20th century as '' Antrodemus'', but a study of the abundant remains from the Cleveland-Lloyd Dinosaur Quarry returned the name "''Allosaurus''" to prominence. As one of the first well-known theropod dinosaurs, it has long attracted attention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type (zoology)
In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to anchor or centralizes the defining features of that particular taxon. In older usage (pre-1900 in botany), a type was a taxon rather than a specimen. A taxon is a scientifically named grouping of organisms with other like organisms, a set that includes some organisms and excludes others, based on a detailed published description (for example a species description) and on the provision of type material, which is usually available to scientists for examination in a major museum research collection, or similar institution. Type specimen According to a precise set of rules laid down in the International Code of Zoological Nomenclature (ICZN) and the ''International Code of Nomenclature for algae, fungi, and plants'' (ICN), the scientific name of every taxon is al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ilium (bone)
The ilium () (: ilia) is the uppermost and largest region of the coxal bone, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, with the exception of some snake species which have a tiny bone considered to be an ilium. The ilium of the human is divisible into two parts, the body and the wing; the separation is indicated on the top surface by a curved line, the arcuate line, and on the external surface by the margin of the acetabulum. The name comes from the Latin ('' ile'', ''ilis''), meaning "groin" or "flank". Structure The ilium consists of the body and wing. Together with the ischium and pubis, to which the ilium is connected, these form the pelvic bone, with only a faint line indicating the place of union. The body () forms less than two-fifths of the acetabulum; and also forms part of the acetabular fossa. The internal surface of the body is part of the wall of the lesser pelvis and gives o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pubis (bone)
In vertebrates, the pubis or pubic bone () forms the lower and anterior part of each side of the hip bone. The pubis is the most forward-facing ( ventral and anterior) of the three bones that make up the hip bone. The left and right pubic bones are each made up of three sections; a superior ramus, an inferior ramus, and a body. Structure The pubic bone is made up of a ''body'', ''superior ramus'', and ''inferior ramus'' (). The left and right coxal bones join at the pubic symphysis. It is covered by a layer of fat – the mons pubis. The pubis is the lower limit of the suprapubic region. In the female, the pubis is anterior to the urethral sponge. Body The body of pubis has: * a superior border or the pubic crest * a pubic tubercle at the lateral end of the pubic crest * three surfaces (anterior, posterior and medial). The body forms the wide, strong, middle and flat part of the pubic bone. The bodies of the left and right pubic bones join at the pubic symphysis. The r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischium
The ischium (; : ischia) is a paired bone forming the lower and back part of the hip bone. Situated below the ilium (bone), ilium and behind the pubis (bone), pubis, it is one of three regions whose fusion creates the coxal bone. The superior portion of this region forms approximately one-third of the acetabulum. Structure The ischium is made up of three parts–the body, the superior ramus and the inferior ramus. The body contains a prominent ischial spine, spine, which serves as the origin for the superior gemellus muscle. The indentation inferior to the spine is the lesser sciatic notch. Continuing down the posterior side, the ischial tuberosity is a thick, rough-surfaced prominence below the lesser sciatic notch. This is the portion ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla
In vertebrates, the maxilla (: maxillae ) 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. Anatomy Structure The maxilla is a paired bone - the two maxillae unite with each other at the intermaxillary suture. The maxilla consists of: * The body of the maxilla: pyramid-shaped; has an orbital, a nasal, an infratemporal, and a facial surface; contains the maxillary sinus. * Four processes: ** the zygomatic process ** the frontal process ** the alveolar process ** the palatine process It has three surfaces: * the anterior, posterior, medial Features of the maxilla include: * t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
