Eardasaurus Powelli
''Eardasaurus'' is a genus of thalassophonean pliosaurid from the middle Jurassic Oxford Clay Formation. The animal would have measured over long (the tail was not fully preserved) and possessed a high amount of teeth relative to other pliosaurs. Its teeth show distinct ridges formed by the tooth enamel, some of which are very pronounced and similar to carinae, giving the teeth a cutting edge. History and naming The remains of ''Eardasaurus'' were discovered H. Philip Powell in the Oxford Clay Formation near Yarnton in 1994. The only known fossil and holotype, specimen OUMNH PAL-J.2247 (previously listed as OUMNH J.02247), was unearthed from the Peterborough Member of the formation, which indicates that it lived during the Callovian stage of the Jurassic. The specimen is fairly complete and partially articulated, preserving both the cranium and mandible, large parts of the vertebral column as well as ribs and gastralia as well as the remains of the left fore- and hindlimbs. The ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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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 subd ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Maxillae
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 nasa ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Anguanax Zignoi
''Anguanax'' is an extinct genus of basal pliosaurid known from the Late Jurassic (Oxfordian stage) Rosso Ammonitico Veronese Formation of northern Italy. It contains a single species, ''Anguanax zignoi'', known from a partially complete individual, representing the first articulated skeleton of an Italian plesiosaurian. Discovery and naming ''Anguanax'' is known solely from the holotype MPPL 18797, currently housed at the Museo Paleontologico e della Preistoria ‘P. Leonardi’ in Ferrara. The skeleton, still articulated in several blocks of limestone, consists of a partial skull including the lower jaw, 32 isolated teeth, neck, back and tail vertebrae, a right pectoral girdle, a partial left humerus, a left radius, a left ulna, three left carpals, a partial pelvis, a femur, two epipodials, isolated metapodials and phalanges. It was collected during the 1980s from a nodular and cherty limestone interval at the Kaberlaba quarry in the Asiago Municipality of the Vicenza ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Marmornectes Candrewi
''Marmornectes'' is a genus of pliosaurid known from the Middle Jurassic of Bedfordshire, United Kingdom. Description ''Marmornectes'' is known from the holotype BEDFM 1999.201, an articulated partial skeleton which includes the skull. It was collected in 1999 from the ''Sigaloceras enodatum'' ammonoid subzone of the Peterborough Member, Oxford Clay Formation, which dates to the early Callovian stage of the late Middle Jurassic, about 164.7-163.5 million years ago. It was found in the monotypic locality of Quest Pit, east of Stewartby. It was a longirostrine pliosaurid with seven autapomorphies, and is most similar to ''Peloneustes philarchus''. Nevertheless, a cladistic analysis found it to be basal to ''Peloneustes'' and other pliosaurids. An undescribed pliosaurid, NHMUK R2439, was found to be the sister taxon of this genus. Etymology ''Marmornectes'' was first named by Hilary F. Ketchum and Roger B. J. Benson in 2011 and the type species is ''Marmornectes cand ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Hauffiosaurus Tomistomimus
''Hauffiosaurus'' is an extinct genus of Early Jurassic (early Toarcian stage) pliosaurid plesiosaur known from Holzmaden of Germany and from Yorkshire of the United Kingdom. It was first named by Frank Robin O’Keefe in 2001 and the type species is ''Hauffiosaurus zanoni''. In 2011, two additional species were assigned to this genus: ''H. longirostris'' and ''H. tomistomimus''. Description The holotype specimen of ''Hauffiosaurus'', housed in the Hauff Museum, is an almost complete and articulated skeleton, found from the Posidonien-Schiefer, dating to early Toarcian stage of the Early Jurassic. The holotype specimen preserved in a single block of the original matrix, exposed in ventral view. The body outline visible around the specimen is an artifact of preparation, not preservation; no remains of soft tissue were preserved. The skeleton was discovered during the early 19th Century, in beds of the famous Posidonien-Schiefer lagerstätte at Holzmaden, Baden-Württemberg, in s ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Brachaucheninae
Thalassophonea is an extinct clade of pliosaurids from the Middle Jurassic to the early Late Cretaceous (Callovian to Turonian) of Australia, Europe, North America and South America. ''Thalassophonea'' was erected by Roger Benson and Patrick Druckenmiller in 2013. The name is derived from Greek ''thalassa'' (θάλασσα), "sea", and ''phoneus'' (φονεύς), "murderer". It is a stem-based taxon defined as "all taxa more closely related to ''Pliosaurus brachydeirus'' than to '' Marmornectes candrewi''". It includes the short necked and large headed taxa that typify the family. Classification The following cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ... follows an analysis by Benson & Druckenmiller (2014). References Middle Jurassic first appearances ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tooth Enamel
Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, cementum, and dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. Calcium hardens the tooth enamel. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed on the tooth while the tooth develops wit ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Lacrimal Bone
The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of the lacrimal bone function in the process of lacrimation or crying. Specifically, the lacrimal bone helps form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of the bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears or lacrimal fluid, from the lacrimal glands, collect in this sac during excessive lacrimation. The fluid then flows through the nasolacrimal duct and into the nasopharynx. This drainage results in what is commonly referred to a runny nose during excessive crying or tear production. Injury or fracture of the lacrimal bone can result in posttraumatic obstruction of the lacrimal pathways. Structure Lateral or orbital surface The lateral or orbital surface i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Squamosal
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]   |
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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 ar ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |