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Coelognathosuchia
Coelognathosuchia is an extinct clade of neosuchian crocodyliforms that includes all taxa more closely related to the family Pholidosauridae than to ''Bernissartia fagesii'' or Eusuchia. Martin ''et al.'' (2014) named the clade after finding goniopholidids and pholidosaurids to group together in their phylogenetic analysis of crocodyliform evolutionary relationships. In their analysis, Pholidosauridae was monophyletic and Goniopholididae was paraphyletic, being an assemblage of successively more basal taxa within Coelognathosuchia. Coelognathosuchia itself was positioned near the base of the larger clade Neosuchia as the sister group to a clade containing the Early Cretaceous neosuchian ''Bernissartia'' and Eusuchia, the group that includes all modern crocodilians and their closest extinct relatives. Martin ''et al.'' named Coelognathosuchia from the Greek (, "concave"), (, "jaw") and (, "crocodile"), after a small depression on the surface of the skull between the maxill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neosuchia
Neosuchia is a clade within Mesoeucrocodylia that includes all modern extant crocodilians and their closest fossil relatives. It is defined as the most inclusive clade containing all crocodylomorphs more closely related to ''Crocodylus niloticus'' (the Nile Crocodile) than to ''Notosuchus terrestris''. Members of Neosuchia generally share a crocodilian-like bodyform adapted to freshwater aquatic life, as opposed to the terrestrial habits of more basal crocodylomorph groups. The earliest neosuchian is suggested to be the Early Jurassic ''Calsoyasuchus'', which lived during the Sinemurian and Pliensbachian stages in North America. It is often identified as a member of Goniopholididae, though this is disputed, and the taxon may lie outside Neosuchia, which places the earliest records of the group in the Middle Jurassic. Characteristics A tooth notch between the maxilla and premaxilla is a basal characteristic of the Neosuchia, although it is lost in some more derived forms, most nota ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.1 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias limestone from S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodilian
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria. Members of the order's total group, the clade Pseudosuchia, appeared about 250 million years ago in the Early Triassic period, and diversified during the Mesozoic era. The order Crocodilia includes the true crocodiles (family Crocodylidae), the alligators and caimans (family Alligatoridae), and the gharial and false gharial (family Gavialidae). Although the term 'crocodiles' is sometimes used to refer to all of these, crocodilians is a less ambiguous vernacular term for members of this group. Large, solidly built, lizard-like reptiles, crocodilians have long flattened snouts, laterally compressed tails, and eyes, ears, and nostrils at the top o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dyrosauridae
Dyrosauridae is a family of extinct neosuchian crocodyliforms that lived from the Late Cretaceous (Maastrichtian) to the Eocene. Dyrosaurid fossils are globally distributed, having been found in Africa, Asia, Europe, North America and South America. Over a dozen species are currently known, varying greatly in overall size and cranial shape. A majority were aquatic, some terrestrial and others fully marine (see locomotion below), with species inhabiting both freshwater and marine environments. Ocean-dwelling dyrosaurids were among the few marine reptiles to survive the Cretaceous–Paleogene extinction event. The dyrosaurids were a group of mostly marine, long jawed, crocodile-like quadrupeds up to long. The largest dyrosaurid was probably ''Phosphatosaurus'' estimated at in length. Based on bone tissue evidence, it has been hypothesized that they were slow-growing near-shore marine animals with interlocking closed jaws, able to swim as well as walk on land. External nostrils at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antorbital Fenestra
An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with archosauriforms, first appearing during the Triassic Period. Among extant archosaurs, birds still possess antorbital fenestrae, whereas crocodylians have lost them. The loss in crocodylians is believed to be related to the structural needs of their skulls for the bite force and feeding behaviours that they employ.Preushscoft, H., Witzel, U. 2002. Biomechanical Investigations on the Skulls of Reptiles and Mammals. Senckenbergiana Lethaea 82:207–222.Rayfield, E.J., Milner, A.C., Xuan, V.B., Young, P.G. 2007. Functional Morphology of Spinosaur "Crocodile Mimic" Dinosaurs. JVP. 27(4):892–901. In some archosaur species, the opening has closed but its location is still marked by a depression, or fossa, on the surface of the skull called the antorbital fossa. The antorbital fenestra houses a paranasal sinus that is confluent with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from the ... [...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] |
Supratemporal 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] |
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] |
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , of which the eye occupies . The orbital contents comprise the eye, the orbital and retrobulbar fascia, extraocular muscles, cranial nerves II, III, IV, V, and VI, blood vessels, fat, the lacrimal gland with its sac and duct, the eyelids, medial and lateral palpebral ligaments, cheek ligaments, the suspensory ligament, septum, ciliary ganglion and short ciliary nerves. Structure The orbits are conical or four-sided pyramidal cavities, which open into the midline of the face and point back into the head. Each consists of a base, an apex and four walls."eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009 Openings There are two important foramina, or windows, two important fissu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jugal
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] |
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] |
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