dinochecker
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DEINOCHEIRUS

a gigantic plant-eating ornithomimid dinosaur from the Late Cretaceous of Mongolia.
deinocheirus.png
Pronunciation: DIEN-o-KIE-rus
Meaning: Terrible hands
Author/s: Osmolska et al. (1970)
Synonyms: None known
First Discovery: Omnogovi, Mongolia
Chart Position: 174

Deinocheirus mirificus

Halszka Osmólska coined Deinocheirus for a pair of never before seen eight-feet long clawed arms that Professor Zofia Kielan-Jaworowska found on 9 July 1965 during a Polish-Mongolian expedition to the Gobi Desert. Further remains were later found strewn around the same site, including bones that had been gnawed on by the areas resident tyrannosaurid, Tarbosaurus bataar. And while there wasn't enough evidence to paint an accurate picture of what it looked like the magnitude of its remains prompted much speculation for decades.

The predictable predicted that the arms belonged to potentially the biggest carnivore of all time, while others suggested that the owner may have been akin to a sloth, albeit a gigantic sloth, and its ridiculously huge claws were used to snag branches or keep would-be predators at bay. Although huge, its arms were quite modest for the size of the shoulder blade to which they were attached, the areas for muscle attachment were small, and features of the wrists suggest low flexibility. Still, other quirks of its arms, hands, fingers and claws hinted at a kinship with ornithomimosaurs of a primitive stamp but, unsurprisingly, not all paleontologists agreed.

Deinocheirus lacked some of the features typical of "Ostrich mimics" and by various experts at different times it has also been mentioned as a megalosauroid, a carnosaur, a coelurosaur, and a straddler of both Carnosauria and Coelurosauria. In fact, several scientific analyses by experts in their field were unable to resolve its relationships and until further and more complete remains presented themselves that wasn't likely to change. However, change things did, as two new specimens from Altan uul IV and Bugeen Tsav (the former a subadult, the latter even bigger than the holotype with a humerus 998 mm long) shed some much needed light on this enigmatic critter. But, alas, the "new" fossil sites had been looted before paleontologists arrived, and poachers made off with the head, hands and feet.

The presence of gastroliths (gizzard stones, intentionally swallowed by herbivores to grind plant matter) showed that it was far from the ferocious meat-shredding carnivore that many had wished for, and with an expanded, forward-tilting pelvis to anchor wads of muscle and relatively short and heavily-built legs with a longer thigh to shin ratio it was not a swift-running animal. Long spines protruding from its vertebrae show that Deinocheirus may have been sail-backed, or perhaps hump-backed, which is weird enough. But what turned out to be its missing robust and wide-clawed feet were repatriated to Mongolia recently, along with a broad-beaked skull, so a complete Deinocheirus currently looks something like a duck-billed ostrich camel.

Whether it actually owns this skull remains to be seen, but what is apparent is that Deinocheirus is the tallest amongst known theropods, though not the longest nor heaviest, and likely towered over everything that looked upon it as lunch.
(Terrible hands that look peculiar)Etymology
Deinocheirus is derived from the Greek "deinos" (terrible) and "kheir" (hand) because of its very large forelimbs and strong claws. The species epithet (or specific name), mirificus, means "peculiar" in Latin, and rounds things up nicely.
Discovery
The first fossils of Deinocheirus were discovered at Altan Uul III, site 2, in the Nemegt Formation, Omnogovi, Mongolia, by Professor Zofia Kielan-Jaworowska on 9th July 1965, during a joint Polish-Mongolian expedition to the Gobi. The holotype (ZPal MgD-I/6) includes both forelimbs, shoulder girdle, partial vertebrae and a few ribs.
Estimations
Timeline:
Era: Mesozoic
Epoch: Late Cretaceous
Stage: Maastrichtian
Age range: 71-66 mya
Stats:
Est. max. length: 11 meters
Est. max. hip height: 3.5 meters
Est. max. weight: 3 tons
Diet: Omnivore
References
• Osmólska H. and Roniewicz E. (1970) "Deinocheiridae, a new family of theropod dinosaurs".
• Senter P. and Robins H.J. (2010) "Hip heights of the gigantic theropod dinosaurs Deinocheirus mirificus and Therizinosaurus cheloniformis, and implications for museum mounting and paleoecology".
• Makovicky P.J, Kobayashi Y. and Currie P.J. (2004) "Ornithomimosauria" in Weishampel, Dodson and Osmólska "The Dinosauria: Second Edition". /uk.
• Paul G.S. (2010) "The Princeton Field Guide to Dinosaurs".
• Lee Y-N, Barsbold R, Currie P.J, Kobayashi Y, Lee H-J, Godefroit P, Escuillié F. and Chinzorig T. (2014) Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus.
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To cite this page:
Atkinson, L. "DEINOCHEIRUS :: from DinoChecker's dinosaur archive".
›. Web access: 25th Jun 2017.
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