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Sthenurus
''Sthenurus'' ("strong tail") is an extinct genus of kangaroos. With a length around 3 m (10 ft), some species were twice as large as modern extant species. ''Sthenurus'' was related to the better-known '' Procoptodon''. The subfamily Sthenurinae is believed to have separated from its sister taxon, the Macropodinae (kangaroos and wallabies), halfway through the Miocene, and then its population grew during the Pliocene. Fossil habitats A 1997 study analysed the diets of the fauna at various fossil site localities in South Australia, using stable carbon isotope analysis 13C/12C of collagen. It found that at older localities such as Cooper Creek, the species of ''Sthenurus'' were adapted to a diet of leaves and twigs (browsing) due to the wet climate of the time between 132 and 108 thousand years ago (kya - by thermoluminescence dating and uranium dating), which allowed for a more varied vegetation cover. At the Baldina Creek fossil site 30 kya ( C14 dating), the genu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kangaroo
Kangaroos are marsupials from the family Macropodidae (macropods, meaning "large foot"). In common use, the term is used to describe the largest species from this family, the red kangaroo, as well as the antilopine kangaroo, eastern grey kangaroo, and western grey kangaroo. Kangaroos are indigenous to Australia and New Guinea. The Australian government estimates that 42.8 million kangaroos lived within the commercial harvest areas of Australia in 2019, down from 53.2 million in 2013. As with the terms " wallaroo" and "wallaby", "kangaroo" refers to a paraphyletic grouping of species. All three terms refer to members of the same taxonomic family, Macropodidae, and are distinguished according to size. The largest species in the family are called "kangaroos" and the smallest are generally called "wallabies". The term "wallaroos" refers to species of an intermediate size. There are also the tree-kangaroos, another type of macropod which inhabit the upper branches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diprotodon
''Diprotodon'' (Ancient Greek: "two protruding front teeth") is an extinct genus of marsupial from the Pleistocene of Australia containing one species, ''D. optatum''. The earliest finds date to 1.77 million to 780,000 years ago but most specimens are dated to after 110,000 years ago. Its remains were first unearthed in 1830 in Wellington Caves, New South Wales, and contemporaneous paleontologists guessed they belonged to rhinos, elephants, hippos or dugongs. ''Diprotodon'' was formally described by English naturalist Richard Owen in 1838, and was the first named Australian fossil mammal, and led Owen to become the foremost authority of his time on other marsupials and Australian megafauna, which were enigmatic to European science. ''Diprotodon'' is the largest-known marsupial to have ever lived; it greatly exceeds the size of its closest living relatives wombats and koalas. It is a member of the extinct family Diprotodontidae, which includes other large quadrupedal herbivor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon-14
Carbon-14, C-14, C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz Kurie in 1934. There are three naturally occurring isotopes of carbon on Earth: carbon-12 (C), which makes up 99% of all carbon on Earth; carbon-13 (C), which makes up 1%; and carbon-14 (C), which occurs in trace amounts, making up about 1-1.5 atoms per 10 atoms of carbon in the atmosphere. C and C are both stable; C is unstable, with half-life years. Carbon-14 has a specific activity of 62.4 mCi/mmol (2.31 GBq/mmol), or 164.9 GBq/g. Carbon-14 decay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phalanges
The phalanges (: phalanx ) are digit (anatomy), digital bones in the hands and foot, feet of most vertebrates. In primates, the Thumb, thumbs and Hallux, big toes have two phalanges while the other Digit (anatomy), digits have three phalanges. The phalanges are classed as long bones. Structure The phalanges are the bones that make up the fingers of the hand and the toes of the foot. There are 56 phalanges in the human body, with fourteen on each hand and foot. Three phalanges are present on each finger and toe, with the exception of the thumb and hallux, big toe, which possess only two. The middle and far phalanges of the fifth toes are often fused together (symphalangism). The phalanges of the hand are commonly known as the finger bones. The phalanges of the foot differ from the hand in that they are often shorter and more compressed, especially in the proximal phalanges, those closest to the torso. A phalanx is named according to whether it is Anatomical terms of locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monodactyl
In biology, dactyly is the arrangement of digits (fingers and toes) on the hands, feet, or sometimes wings of a tetrapod animal. The term is derived from the Greek word () meaning "finger." Sometimes the suffix "-dactylia" is used. The derived adjectives end with "-dactyl" or "-dactylous." As a normal feature Pentadactyly Pentadactyly (from Greek "five") is the condition of having five digits on each limb. It is traditionally believed that all living tetrapods are descended from an ancestor with a pentadactyl limb, although many species have now lost or transformed some or all of their digits by the process of evolution. However, this viewpoint was challenged by Stephen Jay Gould in his 1991 essay "Eight (or Fewer) Little Piggies," where he pointed out polydactyly in early tetrapods and described the specializations of digit reduction. Despite the individual variations listed below, the relationship is to the original five-digit model. In reptiles, the limbs are pentadacty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macropus Giganteus
The eastern grey kangaroo (''Macropus giganteus'': gigantic large-foot; also great grey kangaroo or forester kangaroo) is a marsupial found in the eastern third of Australia, with a population of several million. Although a large ''M. giganteus'' kangaroo male can typically weigh up to and have a length of well over , the scientific name is misleading as the red kangaroo of the semi-arid inland is larger, weighing up to . Taxonomy The eastern grey kangaroo was described by George Shaw in 1790 as ''Macropus giganteus''. Subspecies While two subspecies were recognised by Mammal Species of the World (MSW), there is some dispute as to the validity of this division, and the subspecies are not recognised by the Australian Mammal Society, the IUCN, or the American Society of Mammalogists, which produces the successor of the MSW. Albert Sherbourne Le Souef created the Tasmanian subspecies in 1923, based on coat colour. In 1972 Kirsch and Poole published a paper supporting the concept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatry
In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation. Such speciation may be a product of reproductive isolation – which prevents hybrid offspring from being viable or able to reproduce, thereby reducing gene flow – that results in genetic divergence. Sympatric speciation may, but need not, arise through secondary contact, which refers to speciation or divergence in allopatry followed by range expansions leading to an area of sympatry. Sympatric species or taxa in secondary contact may or may not interbreed. Types of populations Four main types of population pairs exist in nature. Sympatric populations (or species) contrast with parapatric populations, which contact one another in adjacent but not shared ranges and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Kangaroo
The red kangaroo (''Osphranter rufus'') is the largest of all kangaroos, the largest terrestrial mammal native to Australia, and the Largest mammals#Marsupials (Marsupialia), largest extant marsupial. It is found across mainland Australia, except for the more fertile areas, such as southern Western Australia, the eastern and southeastern coasts, and the rainforests along the northern coast. Taxonomy The initial description of the species by Anselme Gaëtan Desmarest, A.G. Desmarest was published in 1822. The type location was given as an unknown location west of the Blue Mountains (New South Wales), Blue Mountains. The author assigned the new species to the genus ''Kangurus''. In 1842, Gould reassigned the species to the genus ''Osphranter'', a taxon later submerged as a subgenus of ''Macropus''. A taxonomic restructure in 2015 in ''Taxonomy of Australian Mammals'' by Jackson and Groves promoted ''Osphranter'' back to the genus level, redefining the red kangaroo, among others, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
