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Plesiopleurodon Wellesi
''Plesiopleurodon'' (/ˌpliːsiəˈplʊərədɒn/; , meaning “near to”, ''pleuro'', meaning “side”, and ''don'', meaning “tooth”) is an extinct genus of Mesozoic marine reptiles, belonging to the Sauropterygia, known from the Late Cretaceous of North America. It was named by Kenneth Carpenter based on a complete skull with a mandible, cervical vertebra, and a coracoid. In naming the specimen, Carpenter noted "Of all known pliosauroids, ''Plesiopleurodon wellesi'' most closely resembles ''Liopleurodon ferox'' from the Oxfordian of Europe, hence the generic reference." It was initially described as a pliosauroid due to it short neck, a common trait of the superfamily (although it is in the order Plesiosauria). However, later exploration into the relationships of both groups indicate that not all pliosauroids have short necks and not all plesiosauroids have long necks. Later research indicates it is a member of the Polycotylidae, within the clade Occultonectia. It is d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order (biology)
Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. For some groups of organisms, their orders may follow consist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frontal Bone
In the human skull, the frontal bone or sincipital bone is an unpaired bone which 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 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, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhomaleosaurus
''Rhomaleosaurus'' (meaning "strong lizard") is an extinct genus of Early Jurassic (Toarcian Faunal stage, age, about 183 to 175.6 million years ago) rhomaleosaurid pliosauroid known from Northamptonshire and from Yorkshire of the United Kingdom. It was first named by Harry Seeley in 1874 in paleontology, 1874 and the type species is ''Rhomaleosaurus cramptoni''. It was one of the earliest large marine reptile predators which hunted in the seas of Mesozoic era, measuring about long. Like other pliosaurs, ''Rhomaleosaurus'' fed on ichthyosaurs, ammonites and other Plesiosauria, plesiosaurs. Species ''R. cramptoni'' In July 1848, a fossil of a large plesiosaur was unearthed in an alum quarry at Kettleness, near Whitby, in Yorkshire, England. It was collected from the ''A. bifrons'' ammonite zone of the Whitby Mudstone Formation, dating to the early Toarcian age, about 183 to 180 million years ago. The complete skeleton which preserved the skull, National Museum of Ireland, NMING& ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliosaurus
''Pliosaurus'' (meaning 'more lizard') is an extinct genus of thalassophonean pliosaurid known from the Late Jurassic (Kimmeridgian and Tithonian stages) of Europe and South America. This genus has contained many species in the past but recent reviews found only six (''P. brachydeirus'' (type species), ''P. carpenteri'', ''P. funkei'', ''P. kevani'', ''P. rossicus'' and ''P. westburyensis'') to be definitively valid. One Patagonian species ''P. patagonicus'' likely belongs to a different genus within Brachaucheninae. Currently, ''P. brachyspondylus'' and ''P. macromerus'' are considered dubious, while ''P. portentificus'' is considered undiagnostic. Most European species of ''Pliosaurus'' would have measured around long and weighed over , though some potential specimens indicate a much larger size. Species of this genus are differentiated from other pliosaurids based on seven autapomorphies, including teeth that are triangular in cross section. Their diet would have include ... [...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 mammals 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Bone
The parietal bones ( ) are two bones in the skull which, when joined at a fibrous joint known as a cranial suture, form the sides and roof of the neurocranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin ''paries'' (''-ietis''), wall. Surfaces External The external surface [Fig. 1] is convex, smooth, and marked near the center by an eminence, the parietal eminence (''tuber parietale''), which indicates the point where ossification commenced. Crossing the middle of the bone in an arched direction are two curved lines, the superior and inferior temporal lines; the former gives attachment to the temporal fascia, and the latter indicates the upper limit of the muscular origin of the temporal muscle. Above these lines the bone is covered by a tough layer of fibrous tissue – the epicranial aponeurosis; below them it forms part of the temporal fossa, and affords attachment to the temporal mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenomanian
The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretaceous series (stratigraphy), Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding age. Both age and stage bear the same name. As a unit of geologic time measure, the Cenomanian Age spans the time between 100.5 and 93.9 million years ago (Mya). In the geologic timescale, it is preceded by the Albian and is followed by the Turonian. The Upper Cenomanian starts around at 95 Mya. The Cenomanian is coeval with the Woodbinian of the regional timescale of the Gulf of Mexico and the early part of the Eaglefordian of the regional timescale of the East Coast of the United States. At the end of the Cenomanian, an anoxic event took place, called the Cenomani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belle Fourche Shale
The Belle Fourche Formation or Belle Fourche Shale is a fossiliferous early Late-Cretaceous geologic formation classification in Wyoming. Named for outcrops in Belle Fourche River, Wyoming, this unit name is also used in Montana, North Dakota, and South Dakota. The unit records the gradual opening and expansion of the Greenhorn Cycle of the Western Interior Seaway, and as such is lithologically identical to the Graneros Shale Formation (that is, it is the same formation under a different name). See also * List of fossiliferous stratigraphic units in Montana * Paleontology in Montana * Paleontology in North Dakota * Paleontology in South Dakota * Paleontology in Wyoming Paleontology in Wyoming includes research into the prehistoric life of the U.S. state of Wyoming as well as investigations conducted by Wyomingite researchers and institutions into ancient life occurring elsewhere. The fossil record of the US s ... References * Cretaceous Montana Cretaceous geology of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holotype
A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several examples, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept. For example, the holotype for the butterfly '' Plebejus idas longinus'' is a preserved specimen of that subspecies, held by the Museum of Comparative Zoology at Harvard University. In botany and mycology, an isotype is a duplicate of the holotype, generally pieces from the same individual plant or samples from the same genetic individual. A holotype is not necessarily "ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symphysis
A symphysis (, : symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together of parts or structures. Unlike synchondroses, symphyses are permanent. Examples The more prominent symphyses are: * the pubic symphysis * sacrococcygeal symphysis * intervertebral disc between two vertebrae * in the sternum, between the manubrium and body * mandibular symphysis In human anatomy, the facial skeleton of the skull the external surface of the mandible is marked in the median line by a faint ridge, indicating the mandibular symphysis (Latin: ''symphysis menti'') or line of junction where the two lateral ha ..., in the jaw Symphysis disorders Pubic symphysis diastasis Pubic symphysis diastasis is an extremely rare complication that occurs in women who are giving birth. Separation of the two pubic bones during deli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occultonectia
Polycotylidae is a family of plesiosaurs from the Cretaceous, a sister group to Leptocleididae. They are known as false pliosaurs. Polycotylids first appeared during the Albian stage of the Early Cretaceous, before becoming abundant and widespread during the early Late Cretaceous. Several species survived into the final stage of the Cretaceous, the early Maastrichtian around . The possible latest surviving member ''Rarosaurus'' from the late Maastrichtian is more likely a crocodylomorph. With their short necks and large elongated heads, they resemble the pliosaurs, but closer phylogenetic studies indicate that they share many common features with the Leptocleididae and Elasmosauridae. They have been found worldwide, with specimens reported from New Zealand, Australia, Japan, Morocco, the US, Canada, Eastern Europe, and South America. Phylogeny Cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
