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Amphimachairodus
''Amphimachairodus'' is an extinct genus of large machairodonts. It is also a member of the tribe Homotherini within Machairodontinae and is most closely related to such species as ''Xenosmilus'', ''Homotherium'' itself, and '' Nimravides''. It inhabited Eurasia, Northern Africa and North America during the late Miocene epoch. History and taxonomy The genus ''Amphimachairodus'' was first proposed by Miklos Kretzoi for the species ''Machairodus palanderi''. ''Machairodus horribilis'' was first described in 1903 by Schlosser, who failed to correctly designate a holotype specimen, and thus the species was largely ignored until a 2008 paper redescribed the species and properly designated a lectotype for it. It was subsequently suggested to be reassigned to ''Amphimachairodus'' by Ruiz-Ramoni ''et al.'' (2019). ''Amphimachairodus pliocaenicus'' was described in 1988 by Joan Pons-Moyà based on fossils from the early Pliocene, found on the Iberian Peninsula. But Ruiz-Ramoni ''et ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Miocene
The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million years ago) to 5.333 Ma. The evolution of life The gibbons (family Hylobatidae) and orangutans (genus ''Pongo'') are the first groups to split from the line leading to the hominins, including humans, then gorillas (genus ''Gorilla''), and finally, chimpanzees and bonobos (genus ''Pan (genus), Pan''). The splitting date between hominin and chimpanzee lineages is placed by some between 4 to 8 million years ago, that is, during the Late Miocene. References External links GeoWhen Database - Late Miocene Miocene, .03 Miocene geochronology, 03 Messinian, * Tortonian, * {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurasian
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago and the Russian Far East to the east. The continental landmass is bordered by the Atlantic Ocean and Africa to the west, the Pacific Ocean to the east, the Arctic Ocean to the north, and by Africa, the Mediterranean Sea, and the Indian Ocean to the south. The division between Europe and Asia as two continents is a historical social construct, as many of their borders are over land; thus, in some parts of the world, Eurasia is recognized as the largest of the six, five, or four continents on Earth. In geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on paleomagnetic data. Eurasia covers around , or around 36.2% of the Earth's total land area. It is also home to the largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machairodus Palanderi
''Amphimachairodus'' is an extinct genus of large machairodonts. It is also a member of the tribe Homotherini within Machairodontinae and is most closely related to such species as ''Xenosmilus'', ''Homotherium'' itself, and ''Nimravides''. It inhabited Eurasia, Northern Africa and North America during the late Miocene epoch. Description There was marked sexual dimorphism in ''A. giganteus'', with males being much larger than females. The species ''Amphimachairodus coloradensis'', from the United States (formerly ''Machairodus coloradensis'') was a significantly large animal, about at the shoulder, according to skeletal and life reconstructions, potentially making it one of the largest known felids. All ''Amphimachairodus'' species have a developed mandibular flange, however, ''A. colaradensis'' is distinguishable from ''A. giganteus'' and ''A. kurteni'' by subtle differences in the shape of the mandible and placement of lower carnassials. In size and proportions, the Eurasian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Formula
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology (that is, the relationship between the shape and form of the tooth in question and its inferred function) of the teeth of an animal. Animals whose teeth are all of the same type, such as most non-mammalian vertebrates, are said to have '' homodont'' dentition, whereas those whose teeth differ morphologically are said to have '' heterodont'' dentition. The dentition of animals with two successions of teeth (deciduous, permanent) is referred to as '' diphyodont'', while the dentition of animals with only one set of teeth throughout life is ''monophyodont''. The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed ''polyphyodont''. The dentition of animals in which the teeth are set in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megantereon
''Megantereon'' was a genus of prehistoric machairodontine saber-toothed cat that lived in North America, Eurasia, and Africa. It may have been the ancestor of ''Smilodon''. Taxonomy Fossil fragments have been found in Africa, Eurasia, and North America. It also ranged into southernmost China as well, as a mostly complete skull from Sabretooth Cave, Chongzuo indicates, though it seemed to have been rare in most of Asia due to being ill-adapted to closed forest environments. The oldest confirmed records of ''Megantereon'' are known from the Pliocene of North America and are dated to about 4.5 million years. About 3–3.5 million years ago, it is firmly recorded also from Africa (for example, in Kenya), about 2.5 to 2 million years ago also from Asia. In Europe the oldest remains are known from Les Etouaries (France), a site which is now dated to less than 2.5 million years old. Therefore, a North American origin of ''Megantereon'' has been suggested. However, recent findings of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Each has two surfaces and four borders. Structure The two nasal bones are joined at the midline internasal suture and make up the bridge of the nose. Surfaces The ''outer surface'' is concavo-convex from above downward, convex from side to side; it is covered by the procerus and nasalis muscles, and perforated about its center by a foramen, for the transmission of a small vein. The ''inner surface'' is concave from side to side, and is traversed from above downward, by a groove for the passage of a branch of the nasociliary nerve. Articulations The nasal articulates with four bones: two of the cranium, the frontal and ethmoid, and two of the face, the opposite nasal and the maxilla. Other animals In primitive bony fish and tetrapod ... [...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] |
Sagittal Crest
A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are exceptionally strong jaw muscles. The sagittal crest serves primarily for attachment of the temporalis muscle, which is one of the main chewing muscles. Development of the sagittal crest is thought to be connected to the development of this muscle. A sagittal crest usually develops during the juvenile stage of an animal in conjunction with the growth of the temporalis muscle, as a result of convergence and gradual heightening of the temporal lines. Function A sagittal crest tends to be present on the skulls of adult animals that rely on powerful biting and clenching of their teeth, usually as a part of their hunting strategy. Skulls of some dinosaur species, including tyrannosaurs, possessed well developed sagittal crests. Among mammals, dogs, cats, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zygomatic Arch
In anatomy, the zygomatic arch, or cheek bone, is a part of the skull formed by the zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the opening of the ear) and the temporal process of the zygomatic bone (the side of the cheekbone), the two being united by an oblique suture (the zygomaticotemporal suture); the tendon of the temporal muscle passes medial to (i.e. through the middle of) the arch, to gain insertion into the coronoid process of the mandible (jawbone). The jugal point is the point at the anterior (towards face) end of the upper border of the zygomatic arch where the masseteric and maxillary edges meet at an angle, and where it meets the process of the zygomatic bone. The arch is typical of '' Synapsida'' (“fused arch”), a clade of amniotes that includes mammals and their extinct relatives, such as ''Moschops'' and '' Dimetrodon''. Structure The zygomatic process of the temporal arises by two roots: * an ''anter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neontology
Neontology is a part of biology that, in contrast to paleontology, deals with living (or, more generally, '' recent'') organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct. For example: * The moose (''Alces alces'') is an extant species, and the dodo (''Raphus cucullatus'') is an extinct species. * In the group of molluscs known as the cephalopods, there were approximately 600 extant species and 7,500 extinct species. A taxon can be classified as extinct if it is broadly agreed or certified that no members of the group are still alive. Conversely, an extinct taxon can be reclassified as extant if there are new discoveries of living species ("Lazarus species"), or if previously-known extant species are reclassified as members of the taxon. Most biologists, zoologists, and botanists are in practice neontologists, and the term neontologist is used largel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and borders fourteen countries by land, the most of any country in the world, tied with Russia. Covering an area of approximately , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two Special Administrative Regions (Hong Kong and Macau). The national capital is Beijing, and the most populous city and financial center is Shanghai. Modern Chinese trace their origins to a cradle of civilization in the fertile basin of the Yellow River in the North China Plain. The semi-legendary Xia dynasty in the 21st century BCE and the well-attested Shang and Zhou dynasties developed a bureaucratic political system to serve hereditary monarchies, or dyna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smilodon
''Smilodon'' is a genus of the extinct machairodont subfamily of the felids. It is one of the most famous prehistoric mammals and the best known saber-toothed cat. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats. ''Smilodon'' lived in the Americas during the Pleistocene epoch (2.5 Year#mya, mya – 10,000 years ago). The genus was named in 1842 based on fossils from Brazil; the generic name means "scalpel" or "two-edged knife" combined with "tooth". Three species are recognized today: ''S. gracilis'', ''S. fatalis'', and ''S. populator''. The two latter species were probably descended from ''S. gracilis'', which itself probably evolved from ''Megantereon''. The hundreds of individuals obtained from the La Brea Tar Pits in Los Angeles constitute the largest collection of ''Smilodon'' fossils. Overall, ''Smilodon'' was more robustly built than any Neontology, extant cat, with particularly well-d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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