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16.12.2015 19:58 - Encyclopedia Largest prehistoric animals Vol.1 Vertebrates part1 Mammals ch.5 Proboscideans-Mammuthus
Автор: valentint Категория: Забавление   
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Genus † Mammuthus
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A mammoth is any species of the extinct genus Mammuthus, proboscideans commonly equipped with long, curved tusks and, in northern species, a covering of long hair. They lived from the Pliocene epoch (from around 5 million years ago) into the Holocene at about 4,500 years ago in Africa, Europe, Asia, and North America. They were members of the family Elephantidae, which also contains the two genera of modern elephants and their ancestors. Mammoths stem from an ancestral species called M. africanavus, the African mammoth. These mammoths lived in northern Africa and disappeared about 3 or 4 million years ago. Descendants of these mammoths moved north and eventually covered most of Eurasia. These were M. meridionalis, the "southern mammoths".
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Mammuthus subplanifrons
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Mammuthus subplanifrons,or the South african mammoth, is the oldest representative of the genus Mammuthus, appearing around 5 million years ago during the early Pliocene in what is today South Africa and countries of East Africa, especially Ethiopia. They already presented some of the unique characteristics of mammoths like the spirally, twisting tusks. It was 3.68 metres (12.1 ft) tall at the shoulder and weighed about 9 tonnes (8.9 long tons; 9.9 short tons)


The African mammot
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Mammuthus africanavus (literally, "African ancestor mammoth"), is the second oldest of mammoth species, having first appeared around 3 million years ago during the late Pliocene, with a last appearance around 1.65 million years ago in the early Pleistocene. Its fossils have been found in Chad, Libya, Morocco and Tunisia. M. africanavus was an African mammoth that seems to have lived after M. subplanifrons and is important to researchers of elephants and mammoths because it is considered to be the ancestor of M. meridionalis (Southern mammoth). In turn the descendants of M. meridionalis would go onto to produce some of the more famous mammoth species such as M. trogontherii (Steppe mammoth) and M. primigenius (Woolly mammoth). Critics to this theory however cite that the tusks diverged more widely at the ends which suggests that M. africanavus might just be an evolutionary offshoot to the species that was ‘the’ ancestor.

Mammuthus rumanus
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Mammuthus rumanus is a species of mammoth that lived during the Pliocene what is today the Eastern Europe. Fossil remains have been found in the United Kingdom and Romania.

Recent revalidation of the species Mammuthus rumanus influences several interrelated aspects of mammoth evolution. European material referred to M. rumanus might provide a useful background for the identification of finds from Africa and the Middle East. It seems plausible that M. rumanus originated in Africa c. 3.5 Ma and migrated to Eurasia via the Levant. While remaining poorly known, M. rumanus apparently played a significant role in the dispersal of mammoths to Eurasia, and any additional information on that species might elucidate problems of the earlier stages of mammoth evolution in Africa and their subsequent dispersal

Mammuthus trogontherii
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The steppe mammoth  is an extinct species of Elephantidae that ranged over most of northern Eurasia during the Middle Pleistocene, 600,000-370,000 years ago. It probably evolved in Siberia during the early Pleistocene from Mammuthus meridionalis. It was the first stage in the evolution of the steppe and tundra elephants and an ancestor of the woolly mammoth of later glacial periods.
There is confusion about the correct taxicological name for the Steppe Mammoth, either Mammuthus armeniacus (Falconer 1857) or Mammuthus trogontherii (Pohlig 1885). Falconer used material from Asian sources while Pohlig worked with fossil remains from Europe and both names appear in scientific publications, adding to the confusion. A first taxonomical overhaul was done by Maglio 1973 who decided that both names were synonyms, armeniacus being the older, hence the preferred name. However in Shoshoni & Tassy 1996 it was decided that the description of Pohlig prevailed, and consequently the correct name for the steppe mammoth is M. trogontherii. It is unclear if both forms are indeed identical and authors tend to use the name M. trogontherii for European material and M. armeniacus for Asian remains.
Several Japanese mammoth varieties from the early Pleistocene have been named, but all are now thought to be synonyms of M. trogontherii.
The steppe mammoth had a short skull compared to M. meridionalis as well as a smaller jaw. The males had spiral tusks with a recurved tip that could grow as long as 5.2 metres in old bulls, females on the other side had thinner and slightly curved tusks.
With several individuals reaching 4 m  tall at the shoulders it is among the largest proboscideans to have ever lived (along with M. meridionalis, M. columbi and Deinotherium) or perhaps the largest. A skeleton mounted on the Azov Museum reaches 4.5 m  at the shoulder though this figure might be overestimated because the vertebrae have been placed between the tips of the shoulder blades. Another individual represented by a single humerus 1.45 m  long found in Mosbach Sande, Germany is estimated to have an in the flesh shoulder height of 4.5 m, weighed between 9–10 metric tons  and might be the largest mammoth found yet.
Fossilized teeth are recovered, but skeletal parts are rare. The most complete skeleton of a steppe mammoth yet found was discovered in 1996 in Kikinda, Serbia. It has recently been mounted and put on display. The specimen is a female, which was about 3.7 metres  high, 7 metres  in length and with 2.7 metres  long tusks an estimated mass of 7 tonnes when alive.
Another quite complete steppe mammoth was excavated in the cliffs of West Runton in Norfolk, UK; it preserves its jaws and teeth but is missing the upper part of its skull. A rare skull found in Auvergne, France, in 2008 will be examined by Dick Mol and Frйdйric Lacombat in the Musйe Crozatier in Le Puy-en-Velay. In 1959 Zhou, M. Z described what he called a new species of mammoth, M. sungari, that gained recent notoriety as the largest proboscidean due to a 5.3 metres tall and 9.1 metres  long composite skeletal mount based on two individuals found in 1980.
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However, Wei et al. (2010), who restudied the fossils referred to M sungari, considered this species to be a junior synonym of M. trogontherii. The authors state that some of the fossils are referrable to M. trogontherii, while the others can be referred to M. primigenius, according to morphological characters and measurements.

The Columbian mammoth (Mammuthus columbi) was a species of mammoth, the common name for the extinct elephant genus Mammuthus.
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The Columbian mammoth lived during the Pleistocene epoch, and inhabited North America from the United States, across Mexico, and as far south as Costa Rica. It was one of the last in a line of mammoth species, beginning with M. subplanifrons in the early Pliocene. The Columbian mammoth diverged from the steppe mammoth which had entered North America about 1.5 million years ago. Its closest extant relative is the Asian elephant. The pygmy mammoths of the Channel Islands evolved from Columbian mammoths.The Columbian mammoth reached 4 m (13 ft) at the shoulders, and weighed up to about 10 tonnes. It had long, curved tusks and four molars, which were replaced six times during the lifetime of an individual. Its behaviour was probably similar to that of modern elephants, and it used its tusks and trunk for manipulating objects, fighting, and foraging. Hair, dung and stomach contents have been discovered, but no preserved carcasses are known. The Columbian mammoth preferred open areas, such as parkland landscapes, and fed on sedge, grass, and other plants. It did not live in the Arctic regions of Canada, which were instead inhabited by woolly mammoths. The range of the two species may have overlapped, and genetic evidence suggests that they interbred. Many Columbian mammoths skeletons are known from the same sites, some of these are the results of single incidents such as flash floods, or natural traps in which individuals were accumulated over time.
The Columbian mammoth coexisted with Palaeoamericans, who used its bones for making tools, and the species was also hunted for food and depicted in ancient art. Columbian mammoth remains have been found in association with Clovis culture artefacts, but it is unknown how many of these sites represent human hunting of mammoths. The Columbian mammoth disappeared at the end of the Pleistocene 12,850 years ago, most likely through climate change and consequent shrinkage of its habitat, hunting by humans, or a combination of the two. The species was named after Christopher Columbus, and is the state fossil of Washington.
The Columbian mammoth was first scientifically described by Scottish naturalist Hugh Falconer in 1857, who named the extinct proboscidean Elephas columbi, after Christopher Columbus, the discoverer of America. The animal had been brought to Falconer"s attention by Charles Lyell in 1846, who had sent some fragmentary molars found during the 1838 excavation of the Brunswick Altamaha Canal in Georgia, in the south eastern United States. At the time, such fossils from all of North America were attributed to woolly mammoths (then Elephas primigenius), but Falconer found them to be distinct, and confirmed this after studying additional molars from Mexico, and after examining the internal structure of a Brunswick Canal molar. William Phipps Blake and Richard Owen claimed the name E. texianus was more appropriate for the species, but this was rejected by Falconer, who also suggested that E. imperator and E. jacksoni were based on too fragmentary molars to be properly classified. More material that may be from the same quarry as Facloner"s holotype molar was reported in 2012.
The taxonomy of extinct elephants was complicated by the early 20th century, and in 1942, Henry Fairfield Osborn"s posthumous monograph on the Proboscidea was published, wherein he used various genus and subgenus names that had previously been proposed for mammoth species, such as Archidiskodon, Metarchidiskodon, Parelephas, and Mammonteus. Osborn also retained names for many regional and intermediate subspecies or "varieties", and created recombinations such as Parelephas columbi felicis and Archidiskodon imperator maibeni.Mammoth taxonomy was simplified by various researchers from the 1970s onwards, all species were retained in the genus Mammuthus, and many proposed differences between species were instead interpreted as intraspecific variation.In 2003, palaeontologist Larry Agenbroad summarised current views about North American mammoth taxonomy, and concluded that several species had been declared junior synonyms, and that M. columbi and M. exilis were the only species of mammoth endemic to the Americas. The idea that species such as M. imperator and M. jeffersoni were either more primitive or advanced stages in Columbian mammoth evolution was largely dismissed, and they were regarded as synonyms. In spite of these conclusions, Agenbroad cautioned that American mammoth taxonomy is not yet fully resolved.
Mammuthus columbi is better known as the Columbian mammoth, although it is not actually named after the country Colombia that is in South America, but after the province of British Columbia in Canada. The Columbian mammoth appears to have been one of the most common mammoths roaming North America during the Pleistocene, and is thought to have come from mammoths that crossed the Bering land bridge from Asia into North America during the early Pleistocene at the latest. This would have been possible by fluctuating sea levels that would have been constantly rising and falling in connection with decreasing and increasing glaciations.
Compared to other mammoths, the Columbian mammoth is generally thought to have had a reduced covering of hair from those that were active in Eurasia. This is based upon the fact that North America is generally considered to have been warmer and less frozen than Europe during the Pleistocene, and an extensive covering of hair would have actually hindered the Columbian mammoths ability to cope with the warmer conditions.
One species of mammoth called M. exilis is thought to be descended from M. columbi. Better known as the pygmy mammoth, M. exilis is currently only known from the Californian channel islands where a population of Columbian mammoths are thought to have travelled to when the sea levels were much lower, and land masses larger, only to be cut off from the mainland when sea levels rose again.

As with most of the North American megafauna, the disappearance of the Columbian mammoth remains an uncertain and controversial subject. Hunting by humans is considered to have been a contributing factor, with fossil sites indicating that mammoths were killed and processed by human hunters, although in seemingly insufficient numbers to wipe out the whole population. Climate change has also been taken to be another contributing factor, and combined with increased hunting the stress may have been too great for the population to survive. Other current theories put forward include new diseases brought in from Asia by new migrants such as the first people, but these diseases would have to be so specialised that they would have affected all of the large megafauna while largely having little effect if any upon the smaller animals that exist to this day. Another is that an air burst from a comet exploding in the upper atmosphere similar to the Tunguska event of 1909 caused continent wide devastation that starved the larger animal species into extinction. To further complicate matters some Columbian mammoth remains are claimed to have come from the early Holocene period several thousand years after all of these events are supposed to have wiped out the megafauna. The only thing that remains fairly stable to say at this time is that populations of Columbian mammoths as with other megafauna at this time seem to have declined rapidly to a point that they could not recover from.

*SPECIAL NOTE* - Mammuthus imperator has now been found to be a synonym to Mammuthus columbi (Columbian mammoth)

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The imperial mammoth is one of the largest known mammoth species in the fossil record, and possibly not only the largest mammoth but the largest terrestrial mammal currently known from North America. The imperial mammoth is still eclipsed in terms of size by some other mammoths; however the exact species is not uncertain. Previously the record holder went to Mammuthus sungari, but new analysis of these remains in 2010 has since led to the idea that the largest remains of M. sungari should be moved over to M. trogontherii, better known as the steppe mammoth, making this the largest species.
The imperial mammoth is usually associated with finds within the United States of America, but remains are also known from as far as Southern Mexico and Canada. As such the imperial mammoth covered a broad geographical range much like its counterpart the Columbian mammoth (M. columbi). These two species are often confused with one another due to their similar forms, but the imperial mammoth can be identified from its tusks, the tips of which cross over one another. The imperial mammoth does seem to have suffered the same fate as the Columbian mammoth however by succumbing to the combined effects of climate change and human hunting.

The woolly mammoth (Mammuthus primigenius) is a species of mammoth that lived during the Pleistocene epoch, and was one of the last in a line of mammoth species, beginning with Mammuthus subplanifrons in the early Pliocene.
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The woolly mammoth diverged from the steppe mammoth about 400,000 years ago in eastern Asia. Its closest extant relative is the Asian elephant. The appearance and behaviour of this species are among the best studied of any prehistoric animal because of the discovery of frozen carcasses in Siberia and Alaska, as well as skeletons, teeth, stomach contents, dung, and depiction from life in prehistoric cave paintings. Mammoth remains had long been known in Asia before they became known to Europeans in the 17th century. The origin of these remains was long a matter of debate, and often explained as being remains of legendary creatures. The mammoth was identified as an extinct species of elephant by Georges Cuvier in 1796.

The woolly mammoth was roughly the same size as modern African elephants. Males reached shoulder heights between 2.7 and 3.4 m (8.9 and 11.2 ft) and weighed up to 6 tonnes (6.6 short tons). Females averaged 2.6–2.9 metres (8.5–9.5 ft) in height and weighed up to 4 tonnes (4.4 short tons). A newborn calf weighed about 90 kilograms (200 lb). The woolly mammoth was well adapted to the cold environment during the last ice age. It was covered in fur, with an outer covering of long guard hairs and a shorter undercoat. The colour of the coat varied from dark to light. The ears and tail were short to minimise frostbite and heat loss. It had long, curved tusks and four molars, which were replaced six times during the lifetime of an individual. Its behaviour was similar to that of modern elephants, and it used its tusks and trunk for manipulating objects, fighting, and foraging. The diet of the woolly mammoth was mainly grass and sedges. Individuals could probably reach the age of 60. Its habitat was the mammoth steppe, which stretched across northern Eurasia and North America.
The woolly mammoth coexisted with early humans, who used its bones and tusks for making art, tools, and dwellings, and the species was also hunted for food. It disappeared from its mainland range at the end of the Pleistocene 10,000 years ago, most likely through climate change and consequent shrinkage of its habitat, hunting by humans, or a combination of the two. Isolated populations survived on St. Paul Island until 6,400 years ago and Wrangel Island until 4,000 years ago. After its extinction, humans continued using its ivory as a raw material, a tradition that continues today. It has been proposed the species could be recreated through cloning, but this method is as yet infeasible because of the degraded state of the remaining genetic material.











 

 

 


 


 

 

 




 




 




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Автор: valentint
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