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Sardinian Pika
The Sardinian pika (''Prolagus sardus'') is an extinct species of pika that was endemic to the islands of Sardinia, Corsica and neighbouring Mediterranean islands until its extinction likely in Roman times. Unlike living pikas, which all belong to the genus ''Ochotona,'' the Sardinian pika was the last surviving member of the genus ''Prolagus,'' a genus of pika once widespread throughout western Eurasia and North Africa during the Miocene and Pliocene epochs. Anatomy The full skeletal structure of the Sardinian pika was reconstructed in 1967, thanks to the numerous finds of bones in Corbeddu Cave, which is near Oliena, Sardinia. Some years later, from these remains, the same researchers led by paleontologist Mary R. Dawson from the US were able to create a plaster reconstruction with good accuracy. The Sardinian pika was probably much stockier and more robust than extant species of pikas, and it probably resembled a sort of cross between a large wild rabbit and a pika. The first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Pleistocene
The Chibanian, widely known by its previous designation of Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The Chibanian name was officially ratified in January 2020. It is currently estimated to span the time between 0.770 Ma (770,000 years ago) and 0.126 Ma (126,000 years ago), also expressed as 770–126 ka. It includes the transition in palaeoanthropology from the Lower to the Middle Palaeolithic over 300 ka. The Chibanian is preceded by the Calabrian and succeeded by the proposed Tarantian. The beginning of the Chibanian is the Brunhes–Matuyama reversal, when the Earth's magnetic field last underwent reversal. It ends with the onset of the Eemian interglacial period (Marine Isotope Stage 5). The term Middle Pleistocene was in use as a provisional or "quasi-formal" designation by the International Union of Geological Sciences (IUGS). W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oliena
Oliena (, less correctly ; sc, Ulìana ) is a commune in the province of Nuoro, Sardinia, Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re .... History The territory of Oliena has been inhabited since the Palaeolithic Era until today. The first proofs about the above-mentioned presences have been found inside the Grotta Corbeddu. The Nuragic civilization featured at least 54 villages, 30 nuraghes, sepulchres, buildings with a likely sacred destination were calculated. As part of the medieval Giudicato of Torres, Oliena was one of the of Posada, Sardinia, Posada. Later it was held by the Republic of Pisa. During the war between the Crown of Aragon, Aragonese and the Giudicato of Arborea, the commune was occupied by Eleanor of Arborea's troops. The village, developed in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enhydrictis
''Enhydrictis'' is a genus of extinct mustelid, belonging to the subfamily Galictinae. The type species, and best known, is ''Enhydrictis galictoides'' from the Pleistocene of Sardinia and Corsica. Taxonomy The exact number of species of ''Enhydrictis'' has been a matter of debate. One species, ''Pannonictis'' ''pilgrimi'' has been classified as a belonging to ''Enhydictis'' (as ''Enydrictis ardea''), although this is unlikely. A 2019 study also suggests that the genus '' Oriensictis'' of Asia should be considered a synonym of ''Enhydrictis'' as well. In 2016, a new species from Algeria was described. Known as ''Enhydrictis hoffstetteri'', it is the first member of the genus known from Africa. Other scholars have considered the attribution of this species to ''Enhydrictis'' doubtful, and that the species should be placed in ''Pannonictis'' instead. In 2018 a new species, ''Enhydrictis praegalictoides'' was described from Middle Pleistocene aged sites on Sardinia, which is likely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mustelidae
The Mustelidae (; from Latin ''mustela'', weasel) are a family of carnivorous mammals, including weasels, badgers, otters, ferrets, martens, minks and wolverines, among others. Mustelids () are a diverse group and form the largest family in the suborder Caniformia of the order Carnivora. They comprise about 66 to 70 species in nine subfamilies. Variety Mustelids vary greatly in size and behaviour. The smaller variants of the least weasel can be under in length, while the giant otter of Amazonian South America can measure up to and sea otters can exceed in weight. Wolverines can crush bones as thick as the femur of a moose to get at the marrow, and have been seen attempting to drive bears away from their kills. The sea otter uses rocks to break open shellfish to eat. Martens are largely arboreal, while European badgers dig extensive tunnel networks, called setts. Only one mustelid has been domesticated; the ferret. Tayra are also kept as pets (although they requ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sardinian Dhole
The Sardinian dhole (''Cynotherium sardous'') is an extinct insular canid which was endemic to what is now the Mediterranean islands of Sardinia (Italy) and Corsica (France), which were joined for much of the Pleistocene. It went extinct when humans began to settle on the island. Its scientific name means "dog-beast of Sardinia", the genus name from the and and the specific name from the , alt. form of . The oldest fossils of the ''Cynotherium'' lineage on Sardinia, belonging to the species ''Cynotherium malatestai'' likely ancestral to ''C. sardous'' date to the Early-Middle Pleistocene transition, corresponding to faunal turnover between the older '' Nesogoral'' Faunal Complex and the younger ''Microtus'' ('' Tyrrhenicola'') faunal complex. The genomic analysis of a 21,000 year-old Sardinian dhole specimen indicates that the Sardinian dhole lineage and the Asian dhole lineage diverged from each other 885,000 years ago. Gene flow continued between the two lineages until b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Density
Population density (in agriculture: standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geographical term.Matt RosenberPopulation Density Geography.about.com. March 2, 2011. Retrieved on December 10, 2011. In simple terms, population density refers to the number of people living in an area per square kilometre, or other unit of land area. Biological population densities Population density is population divided by total land area, sometimes including seas and oceans, as appropriate. Low densities may cause an extinction vortex and further reduce fertility. This is called the Allee effect after the scientist who identified it. Examples of the causes of reduced fertility in low population densities are * Increased problems with locating sexual mates * Increased inbreeding Human densities Population density is the number of people per unit of area, usuall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Bed
A bone bed is any geological stratum or deposit that contains bones of whatever kind. Inevitably, such deposits are sedimentary in nature. Not a formal term, it tends to be used more to describe especially dense collections such as Lagerstätte. It is also applied to brecciated and stalagmitic deposits on the floor of caves, which frequently contain osseous remains. In a more restricted sense, the term is used to describe certain thin layers of bony fragments, which occur in well-defined geological strata. One of the best-known of these is the Ludlow Bone Bed, which is found at the base of the Downton Sandstone in the Upper Ludlow series. At Ludlow (England) itself, two such beds are actually known, separated by about . of strata. Although quite thin, the Ludlow Bone Bed can be followed from that town into Gloucestershire, for a distance of . It is almost completely made up of fragments of spines, teeth and scales of ganoid fish. Another well-known bed, formerly known as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical manifestation of its ecological niche. Thus "habitat" is a species-specific term, fundamentally different from concepts such as environment or vegetation assemblages, for which the term "habitat-type" is more appropriate. The physical factors may include (for example): soil, moisture, range of temperature, and light intensity. Biotic factors will include the availability of food and the presence or absence of predators. Every species has particular habitat requirements, with habitat generalist species able to thrive in a wide array of environmental conditions while habitat specialist species requiring a very limited set of factors to survive. The habitat of a species is not necessarily found in a geographical area, it can be the interior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subfossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anagenesis
Anagenesis is the gradual evolution of a species that continues to exist as an interbreeding population. This contrasts with cladogenesis, which occurs when there is branching or splitting, leading to two or more lineages and resulting in separate species. Anagenesis does not always lead to the formation of a new species from an ancestral species. When speciation does occur as different lineages branch off and cease to interbreed, a core group may continue to be defined as the original species. The evolution of this group, without extinction or species selection, is anagenesis. Hypotheses One hypothesis is that during the speciation event in anagenetic evolution, the original populations will increase quickly, and then rack up genetic variation over long periods of time by mutation and recombination in a stable environment. Other factors such as selection or genetic drift will have such a significant effect on genetic material and physical traits that a species can be acknow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolar
The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth distal to the canines, preceded by deciduous molars. Morphology There is always one large buccal cusp, especially so in the mandibular first premolar. The lower second ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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