|
Liaodactylus Primus
''Liaodactylus'' is a genus of filter-feeding ctenochasmatid pterosaur from the Jurassic of China. The genus contains one species, ''L. primus'', described by Zhou ''et al.'' in 2017. As an adaptation to filter-feeding, ''Liaodactylus'' had approximately 150 long, comb-like teeth packed closely together. It is both the earliest known ctenochasmatid and the first filter-feeding pterosaur from the Jurassic Tiaojishan Formation. Later and more specialized ctenochasmatids differ from ''Liaodactylus'' in having longer snouts, smaller openings (or fenestrae) in the skull, and more teeth. Within the Ctenochasmatidae, ''Liaodactylus'' was most closely related to the European '' Ctenochasma''. Discovery and naming There is one specimen of ''Liaodactylus'' known, namely the holotype PMOL-AP00031, which is stored at the Palaeontological Museum of Liaoning. It consists of a complete skull and lower jaws, along with the first two cervical vertebrae. It originates from outcrops located ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxfordian (stage)
The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic Epoch, or the lowest stage of the Upper Jurassic Series. It spans the time between 163.5 ± 1.0 Ma and 157.3 ± 1.0 Ma (million years ago). The Oxfordian is preceded by the Callovian and is followed by the Kimmeridgian. Stratigraphic definitions The Oxfordian Stage was called "Clunch Clay and Shale" by William Smith (1815–1816); in 1818 W. Buckland described them under the unwieldy title "Oxford, Forest or Fen Clay". The term Oxfordian was introduced by Alcide d'Orbigny in 1844. The name is derived from the English city of Oxford, where the beds are well developed, but they crop out almost continuously from Dorset to the coast of Yorkshire, generally forming low, broad valleys. They are well exposed at Weymouth, Oxford, Bedford, Peterborough, and in the cliffs at Scarborough, Red Cliff and Gristhorpe Bay. Rocks of this age are found also in Uig and Skye. The base of the Oxfordian Stage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a phylogenetic tree#Rooted tree, rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, Phylogenetic diversity, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and cladogenesis, diversification. However, such a correlation does not make a given ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palatine Bone
In anatomy, the palatine bones () are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxillae, they comprise the hard palate. (''Palate'' is derived from the Latin ''palatum''.) Structure The palatine bones are situated at the back of the nasal cavity between the maxilla and the pterygoid process of the sphenoid bone. They contribute to the walls of three cavities: the floor and lateral walls of the nasal cavity, the roof of the mouth, and the floor of the orbits. They help to form the pterygopalatine and pterygoid fossae, and the inferior orbital fissures. Each palatine bone somewhat resembles the letter L, and consists of a horizontal plate, a perpendicular plate, and three projecting processes—the pyramidal process, which is directed backward and lateral from the junction of the two parts, and the orbital and sphenoidal processes, which surmount the vertical part, and are separated by a dee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palate
The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly separated. The palate is divided into two parts, the anterior, bony hard palate and the posterior, fleshy soft palate (or velum). Structure Innervation The maxillary nerve branch of the trigeminal nerve supplies sensory innervation to the palate. Development The hard palate forms before birth. Variation If the fusion is incomplete, a cleft palate results. Function When functioning in conjunction with other parts of the mouth, the palate produces certain sounds, particularly velar, palatal, palatalized, postalveolar, alveolopalatal, and uvular consonants. History Etymology The English synonyms palate and palatum, and also the related adjective palatine (as in palatine bone), are all from the Latin ''palatum'' via Old French ''palat ... [...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] |
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] |
Quadrate Bone
The quadrate bone is a skull bone in most tetrapods, including amphibians, sauropsids (reptiles, birds), and early synapsids. In most tetrapods, the quadrate bone connects to the quadratojugal and squamosal bones in the skull, and forms upper part of the jaw joint. The lower jaw articulates at the articular bone, located at the rear end of the lower jaw. The quadrate bone forms the lower jaw articulation in all classes except mammals. Evolutionarily, it is derived from the hindmost part of the primitive cartilaginous upper jaw. Function in reptiles In certain extinct reptiles, the variation and stability of the morphology of the quadrate bone has helped paleontologists in the species-level taxonomy and identification of mosasaur squamates and spinosaurine dinosaurs. In some lizards and dinosaurs, the quadrate is articulated at both ends and movable. In snakes, the quadrate bone has become elongated and very mobile, and contributes greatly to their ability to swallow very ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadratojugal Bone
The quadratojugal is a skull bone present in many vertebrates, including some living reptiles and amphibians. Anatomy and function In animals with a quadratojugal bone, it is typically found connected to the jugal (cheek) bone from the front and the squamosal bone from above. It is usually positioned at the rear lower corner of the cranium. Many modern tetrapods lack a quadratojugal bone as it has been lost or fused to other bones. Modern examples of tetrapods without a quadratojugal include salamanders, mammals, birds, and squamates (lizards and snakes). In tetrapods with a quadratojugal bone, it often forms a portion of the jaw joint. Developmentally, the quadratojugal bone is a dermal bone in the temporal series, forming the original braincase. The squamosal and quadratojugal bones together form the cheek region and may provide muscular attachments for facial muscles. In reptiles and amphibians In most modern reptiles and amphibians, the quadratojugal is a prominent, strapl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jugal Bone
The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anatomy The jugal bone is located on either side of the skull in the circumorbital region. It is the origin of several masticatory muscles in the skull. The jugal and lacrimal bones are the only two remaining from the ancestral circumorbital series: the prefrontal, postfrontal, postorbital, jugal, and lacrimal bones. During development, the jugal bone originates from dermal bone. In dinosaurs This bone is considered key in the determination of general traits in cases in which the entire skull has not been found intact (for instance, as with dinosaurs in paleontology). In some dinosaur genera the jugal also forms part of the lower margin of either the antorbital fenestra or the infratemporal fenestra, or both. Most commonly, this bone articu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gegepterus
''Gegepterus'' is a genus of ctenochasmatid pterosaur from the Early Cretaceous period of what is now the Yixian Formation of Liaoning, China. Only one species is known, ''G. changi''. History and etymology The genus was named in 2007 by Wang Xiaolin, Alexander Kellner, Zhou Zhonge and Diogenes de Almeida Campos. The type species is ''Gegepterus changi''. The generic name is derived from Manchu ''ge ge'', the title of a princess, in reference to the dainty gracility of the specimen, and a Latinized Greek ''pteron'', "wing". The specific name honors female paleontologist Chang Meemann, who over the years established a cordial relationship between the Chinese and Brazilian authors. In 2008 Wang emended the epithet to ''changae'', but such changes are no longer allowed by the ICZN. It is known from two specimens. The first is holotype IVPP V 11981, which was in 2001 found in grey shales from the lower part of the formation (estimated at 125 million years old), near the city of B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Bone
The angular is a large bone in the lower jaw (mandible) of amphibians and reptiles (birds included), which is connected to all other lower jaw bones: the dentary (which is the entire lower jaw in mammals), the splenial, the suprangular, and the articular. It is homologous to the tympanic bone in mammals, due to the incorporation of several jaw bones into the mammalian middle ear early in mammal evolution. In therapsids (mammal ancestors and their kin), the lower jaw is made up of the dentary (the mandible in mammals) and a group of smaller "postdentary" bones near the jaw joint. As the dentary increased in size over million of years, two of these postdentary bones, the articular and angular, became increasingly reduced and the dentary eventually made direct contact with the upper jaw. These postdentary bones, even before their articular function was lost, probably transmitted sound vibrations to the stapes and, in some therapsids, a bent plate that might have supported a membrane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear). It is connected to the temporal bones by the temporomandibular joints. The bone is formed prenatal development, in the fetus from a fusion of the left and right mandibular prominences, and the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, p. 59 The word "mandible" derives from the Latin word ''mandibula'', "jawbone" (literally "one used for chewing"), from ''wikt:mandere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Jugal Bone")
