Deinotheriidae

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<nowiki>*</nowiki> Type species of generic name indicated
<nowiki>*</nowiki> Type species of generic name indicated
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==Description==
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==Synopsis==
The Deinotheres, meaning "Terror Beasts," were named so because the first specimens of ''[[Deinotherium]]'' were thought to be the remains of some great predatory animal.  More remains, including a nearly complete skeleton, demonstrated that the deinotheres were actually elephant-like browsers with peculiar, downward-curved tusks in the mandibles.  The function(s) of these tusks remain unknown.
The Deinotheres, meaning "Terror Beasts," were named so because the first specimens of ''[[Deinotherium]]'' were thought to be the remains of some great predatory animal.  More remains, including a nearly complete skeleton, demonstrated that the deinotheres were actually elephant-like browsers with peculiar, downward-curved tusks in the mandibles.  The function(s) of these tusks remain unknown.
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:''(the following is from Wikipedia)''
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==Introduction==
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'''Deinotheriidae''' ("terrible beasts") is a family of prehistoric elephant-like [[proboscidea]]ns that lived during the [[Tertiary|Tertiary period]], first appearing in Africa, then spreading across southern Asia (Indo-Pakistan) and Europe.  During that time they changed very little, apart from growing much larger in size - by the late Miocene they had become the largest land animals of their time.  Their most distinctive feature was the downward curving tusks on the lower jaw.
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Deinotheres were not very diverse; there are only three known [[genus|genera]]: ''[[Chilgatherium]]''; ''[[Prodeinotherium]]''; and ''[[Deinotherium]]''.  These form an evolutionary succession (with each new genus replacing the preceding one).
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Unlike the various mammoth and mastodont lineages, the deinotheres died out in the early Pleistocene, rather than continuing through the [[ice age]].
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==Description==
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The body shape and proportions of deinotheres were very much like those of modern elephants.  The legs were long, like modern elephants, but the skull was rather flatter than that of true elephants.  The upper jaw lacked [[incisor]] and [[canine]] teeth, but possessed five low-crowned [[molar]]s on each side, with the same number in the lower jaw.  Harris (1976) has shown that deinotheres used their front teeth for crushing their food, and the back teeth for shearing (slicing), the plant material. 
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The front part of the lower jaw was turned downwards, and bore the two tusk-like incisors.  These curved downwards and backwards in a sort of huge hook, and constituted the most distinct feature of the deinotheres.
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==Ecology==
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Harris (1975) argues that deinotheres were "shearing browsers" adapted for feeding on plants above ground level. The way they chewed their food was probably similar to that of modern [[tapir]]s, with the front teeth being used to crush the food, while the second and third molars have a strong vertical shearing action, with little lateral (side to side) movement.  This chewing action differs from both that of [[Gomphotheriidae|gomphotheres]] (lateral grinding) and [[elephant]]s (horizontal shearing). Deinothere molars show little wear, indicating a diet of soft, nongritty, forest vegetation, with the down-turned lower tusks being used for stripping bark or other vegetation.
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''Deinotherium giganteum'' has a more elongate lower forelimb than early and middle Miocene ''Prodeinotherium'', indicating a more efficient stride as an adaptation to the spread of [[savanna]]s in Europe during the late Miocene.  Deinotheres would probably migrate from forest to forest, traversing the wide and (to them) useless grasslands.
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== Relationships ==
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The ancestry and evolutionary relationships of the deinotheres remain obscure.  It has been suggested that they are related to the [[Barytheriidae|barytheres]], due to similarities in the structure of the teeth.  What is clear is that they diverged from the rest of the proboscideans at a very early date.  In the 1970s several researchers placed them in a separate [[order]] to the Proboscidea, but this view is not followed nowadays.
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== Evolutionary history ==
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The oldest known deinothere is ''[[Chilgatherium|Chilgatherium harrisi]]'' from the late [[Oligocene]].  Its fossil remains have been found in the district of Chilga in Ethiopia (hence the name).  This indicates that, like other proboscideans, deinotheres evolved in [[Africa]].  ''Chilgatherium'' was quite small, about midway between a large [[pig]] and a small [[hippopotamus]] in size.
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By the early [[Miocene]], deinotheres had grown to the size of a small elephant, and had migrated to [[Eurasia]].  Several species are known, all belonging to the genus ''Prodeinotherium''.
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During the late middle Miocene these modest-seized proboscideans were replaced by much larger forms across Eurasia.  In Europe, ''Prodeinotherium bavaricum'' appeared in the early Miocene mammal faunal zone MN 4, but was soon replaced by ''Deinotherium giganteum'' in the middle Miocene.  Likewise in Asia, ''Prodeinotherium'' is known from the early Miocene strata in the Bugti Hills, and continued into the middle Miocene Chinji Formation, where it was replaced by ''Deinotherium indicum''.
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While these Miocene deinotheres were dispersed widely and evolved to huge elephant size, they were not as common as the contemporary (but smaller) [[euelephantoidea]].  Fossil remains of this age are known from the France, Germany, Greece, Malta, and northern India and Pakistan. These consist chiefly of teeth and the bones of the skull.
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After the extinction of the [[Indricotheriinae|indricotheres]] at the end of the early Miocene, the deinotheres were (and remained) the largest animals walking the Earth.
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The late Miocene was the heyday of the giant deinotheres.  ''D. giganteum'' was common from [[Vallesian]] and [[Turolian]] localities in Europe.  ''Prodeinotherium'', which was reasonably well represented in the early Miocene of Africa, was succeeded by ''D. bozasi'' at the beginning of the late Miocene.  And in Asia, ''Deinotherium indicum'' was most common in the late Miocene [[Dhok Pathan Formation]].
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Fossil teeth of ''D. giganteum'', from the late Miocene Sinap Formation at the Turkish site of Kayadibi are larger than those from older localities, such as Eppelsheim, Wissberg and Montredon, indicating a tendency for increasing size of members of the species over time.  These were the biggest animals of their day, protected from both predators and rival herbivores by virtue of their huge bulk. Not until the Pleistocene would the largest [[mammoth]]s approach them in size. 
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With the end of the Miocene, deinothere fortunes declined.  ''Deinotherium indicum'' died out about 7 million years ago, possibly driven to extinction by the same process of climate change that had previously eliminated the even more enormous ''[[Indricotherium]]''.  While in Europe, ''Deinotherium giganteum'' continued, albeit with dwindling numbers, until the middle [[Pliocene]]; the most recent specimen is from Romania.
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In its original African homeland, ''Deinotherium'' continued to flourish throughout the Pliocene, and fossils have been uncovered at several of the African sites where remains of [[Hominidae|hominid]]s have also been found.
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The last deinothere species to become extinct was ''Deinotherium bozasi''.  The youngest known specimens are from the Kanjera Formation, Kenya, about one million years ago (early [[Pleistocene]]).  The causes of the extinction of such a successful and long-lived animal are not known, although a small number of other species of African [[megafauna]] also died out at this time.
==References==
==References==
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Harris, J. M. 1978. Deinotherioidea and Barytherioidea. In ''Evolution of African Mammals'' (V. J. Maglio & H. B. S. Cooke, eds.) pp. 315-332. Harvard University Press: Cambridge (Massachusetts).
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[[Robert L. Carroll|Carroll, R.L.]] (1988), ''Vertebrate Paleontology and Evolution'', WH Freeman & Co.
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[[Edwin H. Colbert|Colbert, E. H.]] (1969), ''Evolution of the Vertebrates'', John Wiley & Sons Inc (2nd ed.)
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Gugliotta, Guy (2003) Six New Species of Prehistoric Mammals Discovered in Africa Find Proves Elephants Originated on Continent, Scientist Says, ''Washington Post'', Thursday, December 4, 2003; Page A02
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[[John M. Harris|Harris, J.M.]] (1975) Evolution of feeding mechanisms in the family Deinotheriidae (Mammalia: Proboscidea). ''Zool. J. Linn. Soc.'' 56: 331-362
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_____(1978) Deinotherioidea and Barytherioidea. In ''Evolution of African Mammals'' (V. J. Maglio & H. B. S. Cooke, eds.) pp. 315-332. Harvard University Press: Cambridge (Massachusetts).
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_____(1983), Family Deinotheriidae, in J. M. Harris, ed., ''Koobi Fora research project, Volume 2: The fossil ungulates: Proboscidea, Perissodactyla, and Suidae'', Clarendon Press, Oxfordpp. 22-39.
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[[William J. Sanders|Sanders, W.J.]], 2003, chap 10, Proboscidea, in [[Mikael Fortelius]]  (ed) ''Geology and paleontology of the Miocene Sinap Formation, Turkey'', Columbia University Press, New York
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Sanders, W. J., Kappelman, J. & Rasmussen, D. T., 2004: New large-bodied mammals from the late Oligocene site of Chilga, Ethiopia.  ''Acta Palaeontologica Polonica'' 49 (3): 365-392. [http://app.pan.pl/acta49/app49-365.pdf pdf]
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"Dinotherium", 1911 Encyclopædia Britannica
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Sanders, W. J., J. Kappelman & D. T. Rasmussen. 2004. New large-bodied mammals from the late Oligocene site of Chilga, Ethiopia. ''Acta Palaeontologica Polonica'' 49 (3): 365-392.
 
'''Credits'''
'''Credits'''
[[User:Christopher|Christopher]] 03:11, 3 June 2008 (PDT)
[[User:Christopher|Christopher]] 03:11, 3 June 2008 (PDT)
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Added Wikipedia content [[User:M alan kazlev|M alan kazlev]] 04:14, 3 January 2010 (UTC)

Revision as of 04:14, 3 January 2010

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