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Viatkogorgon
''Viatkogorgon'' is a genus of gorgonopsian (a type of therapsid, the group that includes modern mammals) that lived during the Permian period in what is now Russia. The first fossil was found at the Kotelnich locality near the Vyatka River and was made the holotype of the new genus and species ''V. ivachnenkoi'' in 1999. The generic name refers to the river and the related genus ''Gorgonops''—the gorgons of Greek mythology are often referenced in the names of the group. The specific name honors the paleontologist Mikhail F. Ivakhnenko. The holotype skeleton is one of the most complete gorgonopsian specimens known and includes rarely preserved elements such as gastralia (abdominal ribs) and a sclerotic ring (a bony ring inside the eye). A larger, but poorly preserved specimen has also been assigned to the species. The holotype specimen is about long, including the long skull, making ''Viatkogorgon'' a relatively small gorgonopsian. The assigned specimen is larger, with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorgonopsian
Gorgonopsia (from the Greek Gorgon, a mythological beast, and 'aspect') is an extinct clade of sabre-toothed therapsids from the Middle to Upper Permian roughly 265 to 252 million years ago. They are characterised by a long and narrow skull, as well as elongated upper and sometimes lower canine teeth and incisors which were likely used as slashing and stabbing weapons. Postcanine teeth are generally reduced or absent. For hunting large prey, they possibly used a bite-and-retreat tactic, ambushing and taking a debilitating bite out of the target, and following it at a safe distance before its injuries exhausted it, whereupon the gorgonopsian would grapple the animal and deliver a killing bite. They would have had an exorbitant gape, possibly in excess of 90°, without having to unhinge the jaw. They markedly increased in size as time went on, growing from small skull lengths of in the Middle Permian to bear-like proportions of up to in the Upper Permian. The latest gorgonopsia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclerotic Ring
Sclerotic rings are rings of bone found in the eyes of many animals in several groups of vertebrates, except for mammals and crocodilians. They can be made up of single bones or multiple segments and take their name from the sclera. They are believed to have a role in supporting the eye, especially in animals whose eyes are not spherical, or which live underwater. Fossil sclerotic rings are known for a variety of extinct animals, including ichthyosaurs, pterosaurs, and dinosaurs, but are often not preserved. File:Tawny Frogmouth Skull.jpg, A skull of an extant tawny frogmouth, showing large sclerotic rings. File:Uroplatus_phantasticus_skull1.jpg, A skull of an extant satanic leaf-tailed gecko, showing large sclerotic rings. File:Viatkogorgon skull.png, Skull and sclerotic ring of the gorgonopsian ''Viatkogorgon''. File:Prosaurolophus maximus3.JPG, Sclerotic ring of the hadrosaur ''Prosaurolophus ''Prosaurolophus'' (; meaning "before ''Saurolophus''", in comparison to the late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the sauropsids ( reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Name (zoology)
In zoological nomenclature, the specific name (also specific epithet or species epithet) is the second part (the second name) within the scientific name of a species (a binomen). The first part of the name of a species is the name of the genus or the generic name. The rules and regulations governing the giving of a new species name are explained in the article species description. For example, the scientific name for humans is ''Homo sapiens'', which is the species name, consisting of two names: ''Homo'' is the " generic name" (the name of the genus) and ''sapiens'' is the "specific name". Historically, ''specific name'' referred to the combination of what are now called the generic and specific names. Carl Linnaeus, who formalized binomial nomenclature, made explicit distinctions between specific, generic, and trivial names. The generic name was that of the genus, the first in the binomial, the trivial name was the second name in the binomial, and the specific the proper term for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian–Triassic Extinction Event
The Permian–Triassic (P–T, P–Tr) extinction event, also known as the Latest Permian extinction event, the End-Permian Extinction and colloquially as the Great Dying, formed the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras, approximately 251.9 million years ago. It is the Earth's most severe known extinction event, with the extinction of 57% of biological families, 83% of genera, 81% of marine species and 70% of terrestrial vertebrate species. It was the largest known mass extinction of insects. There is evidence for one to three distinct pulses, or phases, of extinction. The scientific consensus is that the main cause of extinction was the large amount of carbon dioxide emitted by the volcanic eruptions that created the Siberian Traps, which elevated global temperatures, and in the oceans led to widespread anoxia and acidification. Proposed contributing factors include: the emission of much addition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapsid
Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes reptiles and birds. The group includes mammals and every animal more closely related to mammals than to sauropsids. Unlike other amniotes, synapsids have a single temporal fenestra, an opening low in the skull roof behind each eye orbit, leaving a bony arch beneath each; this accounts for their name. The distinctive temporal fenestra developed about 318 million years ago during the Late Carboniferous period, when synapsids and sauropsids diverged, but was subsequently merged with the orbit in early mammals. Traditionally, non-mammalian synapsids were believed to have evolved from reptiles, and therefore described as mammal-like reptiles in classical systematics, and primitive synapsids were also referred to as pelycosaurs, or pelycosaur-gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivore
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other soft tissues) whether through hunting or scavenging. Nomenclature Mammal order The technical term for mammals in the order Carnivora is ''carnivoran'', and they are so-named because most member species in the group have a carnivorous diet, but the similarity of the name of the order and the name of the diet causes confusion. Many but not all carnivorans are meat eaters; a few, such as the large and small cats (felidae) are ''obligate'' carnivores (see below). Other classes of carnivore are highly variable. The Ursids, for example: While the Arctic polar bear eats meat almost exclusively (more than 90% of its diet is meat), almost all other bear species are omnivorous, and one species, the giant panda, is nearly exclusively herbivorous. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postcranial
Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated skeletal elements; these are referred to as ''postcrania''. There is some disagreement over whether the skull and skeleton belong to the same or different animals. One example is the case of a Cretaceous sauropod skull of ''Nemegtosaurus'' found in association with the postcranial skeleton ''Opisthocoelicaudia ''Opisthocoelicaudia'' is a genus of sauropod dinosaur of the Late Cretaceous Period discovered in the Gobi Desert of Mongolia. The type species is ''Opisthocoelicaudia skarzynskii''. A well-preserved skeleton lacking only the head and neck wa ...''. In paleoanthropological studies, reconstruction of relationship between various species/remains is considered to be better supported by cranial characters rather than postcranial c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulcus (morphology)
In biological morphology and anatomy, a sulcus (pl. ''sulci'') is a furrow or fissure (Latin ''fissura'', plural ''fissurae''). It may be a groove, natural division, deep furrow, elongated cleft, or tear in the surface of a limb or an organ, most notably on the surface of the brain, but also in the lungs, certain muscles (including the heart), as well as in bones, and elsewhere. Many sulci are the product of a surface fold or junction, such as in the gums, where they fold around the neck of the tooth. In invertebrate zoology, a sulcus is a fold, groove, or boundary, especially at the edges of sclerites or between segments. In pollen a grain that is grooved by a sulcus is termed sulcate. Examples in anatomy Liver *Ligamentum teres hepatis fissure *Ligamentum venosum fissure *Portal fissure, found in the under-surface of the liver *Transverse fissure of liver, found in the lower surface of the liver *Umbilical fissure, found in front of the liver Lung *Azygos fissure, of ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheek Teeth
Cheek teeth or post-canines comprise the molar and premolar teeth in mammals. Cheek teeth are multicuspidate (having many folds or tubercles). Mammals have multicuspidate molars (three in placentals, four in marsupials, in each jaw quadrant) and premolars situated between canines and molars whose shape and number varies considerably among particular groups. For example, many modern Carnivora possess carnassials, or secodont teeth. This scissor-like pairing of the last upper premolar and first lower molar is adapted for shearing meat. In contrast, the cheek teeth of deer and cattle are selenodont. Viewed from the side, these teeth have a series of triangular cusps or ridges, enabling the ruminants' sideways jaw motions to break down tough vegetable matter. Cheek teeth are sometimes separated from the incisors by a gap called a diastema. Cheek teeth in reptiles are much simpler as compared to mammals. Roles and significance Apart from helping grind the food to properly reduce th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whereas armadillos have none. Structure Adult humans normally have eight incisors, two of each type. The types of incisor are: * maxillary central incisor (upper jaw, closest to the center of the lips) * maxillary lateral incisor (upper jaw, beside the maxillary central incisor) * mandibular central incisor (lower jaw, closest to the center of the lips) * mandibular lateral incisor (lower jaw, beside the mandibular central incisor) Children with a full set of deciduous teeth (primary teeth) also have eight incisors, named the same way as in permanent teeth. Young children may have from zero to eight incisors depending on the stage of their tooth eruption and tooth development. Typically, the mandibular central incisors erupt first, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saber-toothed Cat
Machairodontinae is an extinct subfamily of carnivoran mammals of the family Felidae (true cats). They were found in Asia, Africa, North America, South America, and Europe from the Miocene to the Pleistocene, living from about 16 million until about 11,000 years ago. The Machairodontinae contain many of the extinct predators commonly known as "saber-toothed cats", including the famed genus ''Smilodon'', as well as other cats with only minor increases in the size and length of their maxillary canines. The name means "dagger-tooth", from Greek μάχαιρα (''machaira''), sword. Sometimes, other carnivorous mammals with elongated teeth are also called saber-toothed cats, although they do not belong to the felids. Besides the machairodonts, other saber-toothed predators also arose in the nimravids, barbourofelids, machaeroidines, hyaenodonts and even in two groups of metatherians (the thylacosmilid sparassodonts and the deltatheroideans). Evolution Family Felidae The Mach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
