Therizinosaurus

Name: Therizinosaurus ‭(‬Scythe lizard‭)‬.
Phonetic: Ther-ih-zine-oh-sore-us.
Named By: Evgeny Maleev‭ ‬-‭ ‬1954.
Classification: Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Saurischia,‭ ‬Theropoda,‭ ‬Therizinosauridae.
Species: T.‭ ‬cheloniformis‭ (‬type‭)‬.
Type: Probably herbivorous.
Size: Approximately‭ ‬10‭ ‬meters long.
Known locations: Mongolia.
Time period: Campanian of the Cretaceous.‭
Fossil representation: Usually the large hand claws,‭ ‬and some post cranial remains.‭ ‬Skull unknown.




       What makes Therizinosaurus and others from its group stand out from other dinosaurs are the huge claws that are on the end of its fingers.‭ ‬In Therizinosaurus these claws reached up to one meter long,‭ ‬and there purpose has three main theories.‭ ‬The first is for display,‭ ‬with the larger claws being indicative of reproductive maturity.‭ ‬The second theory which leads on from the first is for inter species combat between two males,‭ ‬in a similar manner that ceratopsian dinosaurs are thought to have used their horns in dominance combat.‭ ‬This could also mean Therizinosaurus using its claws against predatory dinosaurs in self-defence.
       The third theory is that the claws were aids in reaching up into the tree canopy to pull down choice pieces of vegetation,‭ ‬in the same kind of way that a modern day sloth will also use its long claws to reach its food.‭ ‬This might also imply that Therizinosaurus,‭ ‬among others of its group,‭ ‬preferred some plants over others and was more selective in its feeding.‭ ‬It should also be considered that while one answer may be more correct,‭ ‬the claws may have also been used for different purposes depending upon the situation.
       Unfortunately,‭ ‬apart from the claws,‭ ‬only scant partial remains of the rest of the skeleton are known.‭ ‬This meant that for a long time the exact morphology was largely unknown,‭ ‬with very early depictions making Therizinosaurus a predator that used its claws to take down prey.‭ ‬The discovery of more similar dinosaurs towards the end of the twentieth century allowed for the gaps to be filled in,‭ ‬with modern reconstructions of Therizinosaurus being considered more accurate.
       Members of‭ ‬this group are thought to be descended from carnivorous ancestors,‭ ‬but the exact diet of Therizinosaurus is still not absolutely certain because the skull is unknown.‭ ‬Without this it is impossible to look at the dentition and bite characteristics which are required to learn about an animal‭’‬s diet.‭ ‬Other dinosaurs of the Therizinosauridae,‭ ‬were certainly herbivorous,‭ ‬but because carnivores were their immediate known ancestors,‭ ‬it is often speculated that meat may have still formed part of their diet making them omnivorous.
       Therizinosaurus is usually depicted with the standard featherless body of old dinosaur depictions,‭ ‬but sometimes it is also given feathers.‭ ‬It must be remembered that there is no direct evidence to support the existence of feathers on Therizinosaurus.‭ ‬Evidence for feathers mainly comes from the remains of Beipiaosaurus,‭ ‬but at a little over two meters in length,‭ ‬it is one of the smallest members of the group.‭ ‬In contrast Therizinosaurus is one of the largest,‭ ‬and creatures of its size usually have very little if any form of insulation on the grounds of gigantothermy.




Further reading
- New turtle−like reptile in Mongolia (Russian) - Priroda, 1954(3): 106–108. - Evgeny A. Maleev - 1954.
- On the gigantic claws of mysterious Mesozoic reptiles. - Paleontologischeskii Zhurnal, 1970(1): 131-141. - A. K. Rozhdestvensky - 1970.
- Giant claws of Enigmatic Mesozoic Reptiles. - Paleontology Journal, 4(1): 117-125. - A. K. Rozhdestvensky - 1970.
- New data on Therizinosaurus (Therizinosauridae, Theropoda) (Russian)." In Dev�tkin, E.V. and N.M. �novska� (eds.), Paleontologi� i biostratigrafi� Mongolii. Trudy, Sovmestna� Sovetsko−Mongol’ska� paleontologičeska� kspedici�, 3: 76–92. - Rinchen Barsbold - 1976.
- On a new finding of the hindlimb of Therizinosaurus sp. from the Late Cretaceous of Mongolia - Problems on the Geology of Mongolia, 5: 94–98 - A. Perle - 1982.
- A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora) - Journal of Systematic Palaeontology 8 (4): 503–543. - Lindsay E. Zanno - 2010.


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