Deinocheirus ‭(‬Terrible hand‭)

Short Info

Deinocheirus ‭(‬Terrible hand‭)

Phonetic : Die-noe-ky-rus.

Named By : Osmólska‭ & ‬Roniewicz‭ ‬-‭ ‬1970

Diet : Omnivore

Size : Estimated 10-11 meters long

Type of Dinosaur : Large Theropod

Type Species : D.‭ ‬mirificus‭ (‬type‭)

Found in : Mongolia,‭ ‬Nemegt Formation.

When it Lived : Late Cretaceous, 70-66 million years ago

Deinocheirus (/,daInoU’kaIr@s/ DY-noKY-r@s) is the name given to a species belonging to the huge ornithomimosaurs which lived during the Late Cretaceous around 70 million years in the past. In the year 1965 the year 1965, a pair of massive arms, shoulder girdles along with a few other bones of the new dinosaur were found inside the Nemegt Formation of Mongolia. In 1970, this fossil was made the holotype for the sole species in the genus of Deinocheirus mirificus. The Genus name comes from Greek meaning “horrible hand”. The remains of the animal were not discovered over the course of nearly fifty years, and its origins remains unknown. Two additional complete specimens were discovered in 2014, and provided a better understanding of many details of the beast. Some of the new specimens had been stolen from Mongolia earlier in the year however they were returned in 2014.


Deinocheirus mountケラトプスユウタ, CC BY-SA 4.0, via Wikimedia Commons


Deinocheirus was a unique ornithomimosaur that was the largest of the clade with 11 meters (36 feet) long and the weight of 6.4 tons (7.1 shorter tons). While it was a hefty creature, it was also awash with hollow bones, which helped in reducing weight. The arms were amongst the largest among bipedal dinosaurs. They measured 2.4 meters (7.9 feet) long. They had huge blunt claws that adorned the three fingers of its hands. The legs were quite shorter, and had sharp claws. The vertebrae of the skeleton were adorned with tall neural spines, which created the “sail” along its back. The majority of vertebrae as well as others were pneumatized by air sacs that invaded. The tail ended in pygostyle vertebrae, which indicates the existence of a feather-like fan. The skull measured 1.024 meters (3.36 feet) long, and had an elongated bill and a deeper lower jaw that was similar to the jaws of hadrosaurs.


DeinocheirusbcnEduard Solà, CC BY-SA 3.0, via Wikimedia Commons


Deriocheirus’s classification was for a long time unclear It was initially classified as a member of theropod group Carnosauria however, similarities to ornithomimosaurians soon became apparent. When more complete remains were discovered the Deinocheirus was found to be an early ornithomimosaurian closely associated with the smaller genera Garudimimus and Beishanlong and forming the Deinocheiridae Family. The members of this category were not designed to speed, which is not the case with other ornithomimosaurs. Deinocheirus is believed to have been an omnivore; the skull’s shape suggests the consumption of plants. fish scales were discovered in a specimen and gastroliths also were found in the stomach region in the fossil. The claws’ large size could be used for digging and collecting plants. Bones with bite marks from Deinocheirus have been linked to the Tyrannosaurid Tarbosaurus.

The first fossil remains of Deinocheirus were found by Polish Palaeontologist Zofia Kielan-Jaworowska on the 9th of July, 1965 in the Altan Ula III site (coordinates: 43deg33.987’N 100deg28.959’E) in the Nemegt Basin of the Gobi Desert. It was part an Polish group, accompanied by Mongolian Palaeontologist Rinchen Barsbold, during the 1963-1965 expeditions of the Polish-Mongolian palaeontological team, which were organized in collaboration with the Polish Academy of Sciences and the Mongolian Academy of Sciences. The team spent the week of July 9-11, excavating the remains and loading it on the back of a car. The report from 1968 by Kielan-Jaworowska as well as Naydin Dovchin, that summarized the achievements of the expeditions and announced that the remains belonged to theropods’ first family of dinosaurs.

The specimen was found on a small hill within sandstone. It consists of the disarticulated, partial skeleton, with the majority of which may have been worn away prior to the discovery. The specimen comprised both forelimbs, with the exception of claws on the left hand. It also contained the entire shoulder girdle. It also contained the centra comprised of 3 dorsal vertebrae five gastralia (belly ribs) along with two ceratobranchialia. The specimen was designated the Holotype of Deinocheirus Mirificus, identified by Halszka Osmolska and Ewa Roniewicz in the year 1970. The generic name comes of the Greek deinos (deinos) which means “horrible”, and cheir (kheir) which means “hand”, due to the large size and strength of claws that are found on the front limbs. The exact name originates from Latin and translates to “unusual” or “peculiar” due to the unique shape that the front limbs have. The Polish-Mongolian expeditions were noted because they were conducted by women, and were among the first to identify new dinosaurs. Original specimen numbers for the holotype was ZPal-MgD-I/6 However, it was later re-catalogued as MPC D 100/18.

The inaccessibility of the Deinocheirus is a barrier to a full knowledge of this animal more than fifty years and the scientific literature has often declared it to be among one of the most “enigmatic”, “mysterious” or “bizarre” of dinosaurs. The holotype arms were part of an exhibit that traveled consisting of Mongolian dinosaur fossils that toured several nations. in 2012 Phil R. Bell, Philip J. Currie and Yuong-Nam Lee reported the discovery of new parts of the holotype specimen comprising fragments of gastralia discovered by a Korean-Mongolian group that relocated the quarry in 2008. The marks of a bite on two gastralia were identified as belonging to the Tarbosaurus and it was believed that this could be the cause of the dispersed, disassociated condition of the holotype specimen.

In 2013 discoveries of two brand new Deinocheirus specimens was revealed prior to the Society for Vertebrate Paleontology (SVP) conference by Lee Barsbold, Lee Currie and colleagues. They are housed within the Mongolian Academy of Sciences, the two headless specimens were identified as specimens MPC -D 100/127 and MPC -D 100/128. MPC-D 100/128 was a subadult specimen. It was discovered by scientists at the Altan Ula IV locality (coordinates: 43deg36.091’N 100deg27.066’E) of the Nemegt Formation during the Korea-Mongolia International Dinosaur Expedition in 2006 however, it had been affected by the fossil-poaching poachers. A second one, MPC -D 100/127 was discovered by scientists in the Bugiin Tsav locality (coordinates: 43deg54.025’N 99deg58.359’E) in 2009. It’s slightly larger than the holotype and it is easily identified as Deinocheirus from its left forelimb. This consequently helped to identify the previously discovered piece as Deinocheirus. The specimen was also removed by poachers, who removed the skull as well as the feet, hands and hands leaving behind only one toe bone. The bone was probably taken from the quarry following 2002, on the basis of the amount of money found at the site. Skulls, claw bones , and teeth are typically taken by poachers at the basis of the rest of the skulls (which are usually vandalized) due to their marketability. Currie spoke in an interview it was the practice of their team to look into quarries after they were robbed and discover anything of value as well as that the discovery of new fossils of Deinocheirus was a cause for celebration even without poached parts. A digital model of Deinocheirus that was revealed during the SVP presentation was greeted with applause by the palaeontologists who attended as well as the American Palaeontologist Stephen L. Brusatte stated that he has never been so amazed as he was by an SVP presentation, even though new fossils are often presented at the SVP conference.

Following the announcement of the new specimens released, there was speculation that a skull that was stolen was destined for an European museum via trade on the dark market. The poached parts were discovered in the private European collection by French fossil dealer Francois Escuille, who notified Belgian Palaeontologist Pascal Godefroit about them in the year 2011. They suspected that the remains belonged to Deinocheirus and then contacted the Korean-Mongolian group. Escuille then obtained the fossils and donated they to Royal Belgian Institute of Natural Sciences. The fossils recovered comprised skulls and a left hand and feet. The items were collected in Mongolia and later auctioned off to an Japanese buyer, and then resold to an German group (the fossils also traveled via China as well as France). The team concluded that the pieces belonged to MPC-D 100/127 because the toe bone that was left was perfectly positioned in the unfinished matrix that was apposed to a feet, the bone and the matrix matched in colour, and the pieces were belonging to an person that was the same size without overlap in the skeletal components. On May 1, 2014 the fossils were returned into Mongolia by a team that was from the Belgian Museum, during a ceremony that took place in the Mongolian Academy of Sciences. The skeleton, which was reunited, was placed in the Central Museum of Mongolian Dinosaurs in Ulaanbaatar as well as the Tarbosaurus skeleton that had returned following being taken. American Palaeontologist Thomas R. Holtz stated in an interview that the latest Deinocheirus remains appeared to be something that was the “product of a secret love affair between a hadrosaur and Gallimimus”.

In conjunction with the poached parts The two new specimens are nearly the entire skeleton of Deinocheirus. The MPC-D 100/127 covers all of the material, with the exception of mid-dorsal vertebrae the majority of caudal vertebrae, as well as the forelimb on the right side; MPC-D 100/128 fills the holes in the other skeleton. It includes almost all caudal and dorsal vertebrae, the ilium an ischium that is only a fractional size as well as the majority part of the right hindlimb. In 2014 the specimens were described by Lee Barsbold Currie, Yoshitsugu Kobayashi, Hang-Jae Lee Lee Godefroit, Escuillie as well as Tsogtbaatar Chinzorig. Similar events was described earlier in 2014, with Spinosaurus another sail-backed theropod that was known only from a handful of remains since 1912. Poached remains were linked to samples collected by scientists, and Spinosaurus was found to be quite distinct in comparison to other spinosaurids. Both cases proved that the appearance and lifestyle of animals extinct in a state that is not well-studied can’t always be derived from their close relatives. In 2017 the Mongolian government was increasing efforts to seize fossils poached by collectors and return them to the country however, proving their authenticity was now a science and political issue. Thus, a study was conducted to test possibilities of finding fossils from poached collections by using geochemical techniques employing Deinocheirus as well as different Nemegt dinosaurs as an example. In 2018, several massive tridactyl (three-toed) tracks were discovered from the Nemegt location (discovered in 2007 along with the tracks of sauropods). While the tracks appeared identical to the tracks of hadrosaurs but no tracks of hadrosaur hands were discovered and, since Deinocheirus’ feet are believed to be identical to the feet of hadrosaurs and other dinosaurs, it can’t be said to be certain they were created by this Genus.

Deinocheirus is one of the largest ornithomimosaurian (ostrich dinosaur) discovered. The largest known specimen was about 11-12 meters (36-39 feet) in length, and an approximate weight that was 6.4-7 tons (7.1-7.7 shorter tons) as well as an estimate of hip length of 4.4 millimeters (14 feet). Two other known specimens are smaller, with the one holotype is 94% massive, and the tiniest subadult was just 74% larger. If only the holotype arms that were not complete were identified, various sizes were extrapolated through various methods. A study from 2010 found the hips of Deinocheirus at 3.3-3.6 metres (11-12 feet). The weight was previously calculated to be between 2 tons (2.2 short tons) and 12 tonnes (13 short tons). The size of the arms was additionally suggested by comparing arms with the arms of tyrannosaurs although the members of this group didn’t have huge arms, in comparison to their body dimensions.

The skull that is the only one known that is part of the largest of specimens that measures 1.024 meters (3.36 feet) across the anterior premaxilla in the front and the rear of the occipital condyle. The largest part of the skull in the area behind the eyes is just 23 centimeters (9.1 in) large by comparison. The skull was comparable to other ornithomimosaurs by being small and narrow however, it differed in the sense that the snout was much more long. The skull’s bone walls were thin, at least 6 millimeters (0.24 inches). The skull had a round and flattened beak. It would have been covered with Keratin during the course of its life. The nostrils were angled towards the upwards direction, and the nasal bone was a strap that extended above the eyes’ sockets. The outer diameter of sclerotic ring in the eyes was tiny, 8.4 cm (3.3 in) in comparison to that of the head. The lower temporal fenestrae(the openings in the eyelids were closed by the jugal bone, like Gallimimus. Jaws were toothless and downward-turned. The lower jaw was extremely large and deep when compared to the slim and lower upper jaw. The dimension of jaws of lower was more similar to that of tyrannosaurids , but not the other ornithomimosaurs. Its snout is spatulate (flared upwards towards both sides) and was 25 centimeters (9.8 in) broad, which is more than the roof of the skull. This form was similar to that of the snouts of the duck-billed hadrosaurids.

Source: Wikipedia