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Marsupial Mole
Marsupial moles, the Notoryctidae , are highly specialized marsupial mammals, known from two species found at the Australian interior. * ''Notoryctes typhlops'' (southern marsupial mole, known as the ''itjaritjari'' by the Pitjantjatjara and Yankunytjatjara people in Central Australia). * ''Notoryctes caurinus'' (northern marsupial mole, also known as the ''kakarratul'') Notoryctids are small, fossorial mammals that anatomically converge on other fossorial (and distantly related) mammals, such as living golden moles (Chrysochloridae) and extinct epoicotheres (Pholidota). Characteristics In an example of convergent evolution, notoryctids resemble (and fill the ecological niche of) moles from North America and Eurasia and golden moles from Southern Africa. Like chrysochlorids and epoicotheres, notoryctids use their forelimbs and enlarged central claws to dig in a parasagittal (i.e., up and down) plane, as opposed to the "lateral scratch" style of digging that characterizes talpi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Marsupial Mole
The southern marsupial mole (''Notoryctes typhlops''), also known as the itjaritjari () or itjari-itjari, is a mole-like marsupial found in the western central deserts of Australia. It is extremely adapted to a burrowing way of life. It has large, shovel-like forepaws and silky fur, which helps it move easily. It also lacks complete eyes as it has little need for them. It feeds on earthworms and larvae. History of discovery Although the southern marsupial mole was probably known by Aboriginal Australians for thousands of years, the first specimen examined by the scientific community was collected in 1888. Stockman W. Coulthard made the discovery on Idracowra Pastoral Lease in the Northern Territory by following some unusual prints that lead him to the animal lying under a tussock. Not knowing what to do with the strange creature, he wrapped it in a kerosene soaked rag, placed it in a revolver cartridge box and forwarded it to E. C. Stirling, the Director of the South Austral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vestigial
Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species. Examples of vestigial structures (also called degenerate, atrophied, or rudimentary organs) are the loss of functional wings in island-dwelling birds; the human vomeronasal organ; and the hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus and, in plants and algae, also in plastids such as chloroplasts. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that the human mtDNA includes 16,569 base pairs and encodes 13 proteins. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits an examination of the relatedness of populations, and so has become important in anthropology and biogeography. Origin Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William King Gregory
William King Gregory (May 19, 1876 – December 29, 1970) was an American zoologist, renowned as a primatologist, paleontologist, and functional and comparative anatomist. He was an expert on mammalian dentition, and a leading contributor to theories of evolution. In addition he was active in presenting his ideas to students and the general public through books and museum exhibits. Early life He was born in Greenwich Village, New York, on May 19, 1876 to George Gregory and Jane King Gregory. He attended Trinity School and then moved onto Columbia University in 1895, initially at the School of Mines but then transferring to Columbia College. He majored in zoology and vertebrate paleontology under Henry Fairfield Osborn. While still an undergraduate he became Osborn's research assistant and soon after married Laura Grace Foote. He received his undergraduate degree from Columbia in 1900, followed by a masters in 1905, and a doctorate in 1910. Academic career He developed an ... [...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 sock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosaic Evolution
Mosaic evolution (or modular evolution) is the concept, mainly from palaeontology, that evolutionary change takes place in some body parts or systems without simultaneous changes in other parts. Another definition is the "evolution of characters at various rates both within and between species".Carroll R.L. 1997. ''Patterns and processes of vertebrate evolution''. Cambridge University Press. 408 Its place in evolutionary theory comes under long-term trends or macroevolution. Background In the neodarwinist theory of evolution, as postulated by Stephen Jay Gould, there is room for differing development, when a life form matures earlier or later, in shape and size. This is due to allomorphism. Organs develop at differing rhythms, as a creature grows and matures. Thus a " heterochronic clock" has three variants: 1) time, as a straight line; 2) general size, as a curved line; 3) shape, as another curved line. When a creature is advanced in size, it may develop at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riversleigh World Heritage Area
Riversleigh World Heritage Area is Australia's most famous fossil location, recognised for the series of well preserved fossils deposited from the Late Oligocene to more recent geological periods. The fossiliferous limestone system is located near the Gregory River in the north-west of Queensland, an environment that was once a very wet rainforest that became more arid as the Gondwanan land masses separated and the Australian continent moved north. The approximately area has fossil remains of ancient mammals, birds, and reptiles of the Oligocene and Miocene ages, many of which were discovered and are only known from the Riversleigh area; the species that have occurred there are known as the Riversleigh fauna. The fossils at Riversleigh are unusual because they are found in soft freshwater limestone which has not been compacted. This means the animal remains retain their three-dimensional structure, rather than being partially crushed like in most fossil sites. The area is loca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naraboryctes
''Naraboryctes philcreaseri'' is a fossil species of marsupial found at early Miocene deposits of Boodjamulla National Park of Riversleigh area, northwestern Queensland, Australia. Taxonomy It was first named by Michael Archer, Robin Beck, Miranda Gott, Suzanne Hand, Henk Godthelp and Karen Black in 2011 and is the type species of genus ''Naraboryctes''. The generic name means "to drink" (naraba in Garrawa and Waanyi languages of northwestern Queensland) in reference to its rainforest palaeohabitat + "digger" (oryctes in Greek) in reference to its fossorial specializations and close relationship to the extant species of genus ''Notoryctes''. The specific epithet honors Phil Creaser, and is referred to as "Phil Creaser's Drinking Digger". The genus is allied to the family of modern 'marsupial moles', Notoryctidae, two or three species of the extant genus ''Notoryctes''. However, a more recent study showscases that it lacked many of the synapomorphies associated with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambda
Lambda (}, ''lám(b)da'') is the 11th letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed . Lambda gave rise to the Latin L and the Cyrillic El (Л). The ancient grammarians and dramatists give evidence to the pronunciation as () in Classical Greek times. In Modern Greek, the name of the letter, Λάμδα, is pronounced . In early Greek alphabets, the shape and orientation of lambda varied. Most variants consisted of two straight strokes, one longer than the other, connected at their ends. The angle might be in the upper-left, lower-left ("Western" alphabets) or top ("Eastern" alphabets). Other variants had a vertical line with a horizontal or sloped stroke running to the right. With the general adoption of the Ionic alphabet, Greek settled on an angle at the top; the Romans put the angle at the lower-left. The HTML 4 character entity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zalambdodont
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth", from ''mola'', millstone and ''dens'', tooth. Molars show a great deal of diversity in size and shape across mammal groups. The third molar of humans is sometimes vestigial. Human anatomy In humans, the molar teeth have either four or five cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies from individual to individual. Race can also affect the age at which this occurs, with statistical variations between groups. In some cases, it may not even erupt at all. The human mouth contains upper (maxillary) and lower (mand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebra
The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the backbone), and on the other with phylogenetic differences among the vertebrate taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armadillo
Armadillos (meaning "little armored ones" in Spanish) are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, along with the anteaters and sloths. Nine extinct genera and 21 extant species of armadillo have been described, some of which are distinguished by the number of bands on their armor. All species are native to the Americas, where they inhabit a variety of different environments. Armadillos are characterized by a leathery armor shell and long, sharp claws for digging. They have short legs, but can move quite quickly. The average length of an armadillo is about , including its tail. The giant armadillo grows up to and weighs up to , while the pink fairy armadillo has a length of only . When threatened by a predator, ''Tolypeutes'' species frequently roll up into a ball; they are the only species of armadillo capable of this. Etymology T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
