Deinocheirus

Deinocheirus (/ˌdaɪnoʊˈkaɪrəs/ DY-no-KY-rəs) is a genus of large ornithomimosaur that lived during the Late Cretaceous around 70 million years ago. In 1965, a pair of large arms, shoulder girdles, and a few other bones of a new dinosaur were first discovered in the Nemegt Formation of Mongolia. In 1970, this specimen became the holotype of the only species within the genus, Deinocheirus mirificus; the genus name is Greek for "horrible hand". No further remains were discovered for almost fifty years, and its nature remained a mystery. Two more complete specimens were described in 2014, which shed light on many aspects of the animal. Parts of these new specimens had been looted from Mongolia some years before, but were repatriated in 2014.

Deinocheirus was an unusual ornithomimosaur, the largest of the clade at 11 m (36 ft) long, and weighing 6.4 t (7.1 short tons). Though it was a bulky animal, it had many hollow bones which saved weight. The arms were among the largest of any bipedal dinosaur at 2.4 m (7.9 ft) long, with large, blunt claws on its three-fingered hands. The legs were relatively short, and bore blunt claws. Its vertebrae had tall neural spines that formed a "sail" along its back. The tail ended in pygostyle-like vertebrae, which indicate the presence of a fan of feathers. The skull was 1.024 m (3.36 ft) long, with a wide bill and a deep lower jaw, similar to those of hadrosaurs.

The classification of Deinocheirus was long uncertain, and it was initially placed in the theropod group Carnosauria, but similarities with ornithomimosaurians were soon noted. After more complete remains were found, Deinocheirus was shown to be a primitive ornithomimosaurian, most closely related to the smaller genera Garudimimus and Beishanlong, together forming the family Deinocheiridae. Members of this group were not adapted for speed, unlike other ornithomimosaurs. Deinocheirus is thought to have been omnivorous; its skull shape indicates a diet of plants, fish scales were found in association with one specimen and gastroliths were also present in the stomach region of the specimen. The large claws may have been used for digging and gathering plants. Bite marks on Deinocheirus bones have been attributed to the tyrannosaurid Tarbosaurus.

Deinocheirus
Temporal range: Late Cretaceous, 71–69 Ma
Arms and shoulders
Arms and shoulder blades of the holotype specimen in CosmoCaixa, Barcelona
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Clade: Ornithomimosauria
Family: Deinocheiridae
Genus: Deinocheirus
Osmólska & Roniewicz, 1970
Species:
D. mirificus
Binomial name
Deinocheirus mirificus
Osmólska & Roniewicz, 1970

Description

Deinocheirus Scale
Size of three specimens (holotype in green) compared to a human

Deinocheirus is the largest ornithomimosaurian (ostrich dinosaur) discovered; the largest known specimen measured up to 11 m (36 ft) long, with an estimated weight of 6.4 t (7.1 short tons). The two other known specimens are smaller, the holotype being 94% as big while the smallest, a subadult, only 74% as big.[1] When only the incomplete holotype arms were known, various sizes were extrapolated from them by different methods. A 2010 study estimated the hip height of Deinocheirus to be 3.3–3.6 m (11–12 ft).[2] The weight had previously been estimated between 2 tonnes (2.2 short tons) to 12 tonnes (13 short tons). Enormous sizes were also suggested by comparing the arms with those of tyrannosaurs, even though members of that group did not have large arms in proportion to their body size.[3][4][5]

Deinocheirus mirificus forelimb en
Labelled diagram of the left arm and shoulder blade of Deinocheirus

Deinocheirus and Therizinosaurus possessed the longest forelimbs known for any bipedal dinosaurs.[2] The holotype forelimbs measure 2.4 m (7.9 ft) long — the humerus (upper arm bone) is 93.8 cm (36.9 in), the ulna 68.8 cm (27.1 in), and the hand is 77 cm (30 in) — including the 19.6 cm (7.7 in) long recurved claws. Each scapulocoracoid of the shoulder girdle has a length of 1.53 m (5.0 ft). Each half of the paired ceratobranchialia measure 42 cm (17 in). The shoulder-blade was long and narrow, and the deltopectoralis crest was pronounced and triangular. The upper arm (humerus) was relatively slender, and only slightly longer than the hand. The ulna and radius (lower arm bones) were elongate and not firmly connected to each other in a syndesmosis. The metacarpus was long compared to the fingers. The three fingers were about equal in length, the first being the stoutest and the second the longest. Various rough areas and impressions on the forelimbs indicate the presence of powerful muscles. Most articular surfaces of the arm bones were deeply furrowed, indicating that the animal had thick pads of cartilage between the joints. Though the arms of Deinocheirus were large, the ratio between them and the shoulder girdle was less than that of the smaller ornithomimosaur Ornithomimus.[6] The arm bones of Deinocheirus were similar in proportions to those of the small theropod Compsognathus.[7] The wishbone (furcula), an element not known from any other ornithomimosaurs, was U-shaped. The hindlimbs were relatively short, and the thigh bone (femur) was longer than the shin bone (tibia), as is common for large animals. The metatarsus was short and not arctometatarsalian, as in most other theropods. The claw bones of the feet were blunt and broad-tipped instead of tapered, unlike other theropods, but resembled the unguals of large ornithischian dinosaurs. The proportions of the toe bones resembled those of tyrannosaurs, due to the large weight they had to bear.[1]

Deinocheirus vertebrae en
Labelled diagram of some of the vertebrae that form a "sail"

Though Deinocheirus was a bulky animal, its dorsal ribs were tall and relatively straight, indicating that the body was narrow.[8] The ten neck vertebrae were low and long, and progressively shorter backwards from the skull. This resulted in a more S-curved neck than seen in other ornithomimosaurs, due to the larger skull. The neural spines of the twelve back vertebrae became increasingly longer from front to back, the last one being 8.5 times the height of the centrum part. This is almost the same as the highest ratio in the neural spines of the theropod Spinosaurus. The neural spines had a system of interconnecting ligaments, which stiffened the vertebral column allowing it to support the abdomen while transmitting the stress to the hips and hindlimbs.[1] Together, the neural spines formed a tall "sail" along the lower back, hips, and base of the tail, somewhat similar to that of Spinosaurus.[9]

All the vertebrae were highly pneumatised by invading air sacs, except for the atlas bone and the hindmost tail vertebrae, and were thereby connected to the respiratory system. The back vertebrae were as pneumatised as those of sauropod dinosaurs, and had an extensive system of depressions. These adaptations may be correlated with gigantism, as they reduce weight. The six vertebrae of the sacrum were also tall and pneumatised, and all but the first one were fused together at the top, their neural spines forming a neural plate. The ilium, the top hip bone, was also partially pneumatised close to the sacral vertebrae. Part of the pelvis was hypertrophied (enlarged) compared to other ornithomimosaurs, to support the weight of the animal with strong muscle attachments. The front hip bones tilted upwards in life. The tail of Deinocheirus ended in at least two fused vertebrae, which were described as similar to the pygostyle of oviraptorosaurian and therizinosauroid theropods. Ornithomimosaurs are known to have had pennaceous feathers, so this feature suggests that they might have had a fan of feathers at the tail end.[1][10]

Hypothetical Deinocheirus
Life restoration

The only known skull, belonging to the largest specimen, measures 1.024 m (3.36 ft) from the premaxilla at the front to the back of the occipital condyle. The widest part of the skull behind the eyes is only 23 cm (9.1 in) wide in comparison. The skull was similar to those of other ornithomimosaurs in being low and narrow, but differed in that the snout was more elongated. The skull bone walls were rather thin, about 6 mm (0.24 in). It had a rounded, flattened beak, which would have been covered by keratin in life. The nostrils were turned upwards, and the nasal bone was a narrow strap that extended up above the eye sockets. The outer diameter of the sclerotic rings in the eyes was small, 8.4 cm (3.3 in), compared to the size of the skull. The lower temporal fenestrae, openings behind the eyes, were partially closed off by the jugal bones, similar to Gallimimus. The jaws were toothless and down-turned, and the lower jaw was very massive and deep compared to the slender and low upper jaw. The relative size of the lower jaw was closer to that of tyrannosaurids than to other ornithomimosaurs. The snout was spatulate (flared outwards to the sides) and 25 cm (9.8 in) wide, which is wider than the skull roof.[1] This shape is similar to the snout of duck-billed hadrosaurids.[9]

History of discovery

Deinocheirus hands
Holotype specimen MPC-D 100/18 on exhibit in Barcelona

The first known fossil remains of Deinocheirus were discovered by Polish palaeontologist Zofia Kielan-Jaworowska on July 9, 1965, at the Altan Ula III site (coordinates: 43°33.987′N 100°28.959′E / 43.566450°N 100.482650°E) in the Nemegt Basin of the Gobi Desert. She was part of a Polish group accompanied by Mongolian palaeontologist Rinchen Barsbold during the 1963–1965 Polish-Mongolian palaeontological expeditions, which were organised by the Polish Academy of Sciences and the Mongolian Academy of Sciences. The crew spent July 9–11 excavating the specimen and loading it onto a vehicle. A 1968 report by Kielan-Jaworowska and Naydin Dovchin, which summarised the accomplishments of the expeditions, announced that the remains represented a new family of theropod dinosaur.[1][11] The specimen was discovered on a small hill in sandstone, and consists of a partial, disarticulated skeleton, most parts of which had probably eroded away at the time of discovery. The specimen consisted of both forelimbs, excluding the claws of the right hand, the complete shoulder girdle, centra of three dorsal vertebrae, five ribs, gastralia (belly ribs), and two ceratobranchialia. The specimen was made the holotype of Deinocheirus mirificus, named by Halszka Osmólska and Ewa Roniewicz in 1970. The generic name is derived from Greek deinos (δεινός), meaning "horrible", and cheir (χείρ), meaning "hand", due to the size and strong claws of the forelimbs. The specific name comes from Latin and means "unusual" or "peculiar", chosen for the unusual structure of the forelimbs.[6] The Polish-Mongolian expeditions were notable for being led by women, among the first to name new dinosaurs.[12] The original specimen number of the holotype was ZPal MgD-I/6, but it has since been re-catalogued as MPC-D 100/18.[1]

The paucity of known Deinocheirus remains inhibited a thorough understanding of the animal for almost half a century onwards, and the scientific literature often described it as among the most "enigmatic", "mysterious", and "bizarre" of dinosaurs.[1][13][14] The holotype arms went on to become part of a traveling exhibit of Mongolian dinosaur fossils, touring various countries.[15] In 2012, Phil R. Bell, Philip J. Currie, and Yuong-Nam Lee announced the discovery of additional elements of the holotype specimen, including fragments of gastralia, found by a Korean-Mongolian team which re-located the original quarry in 2008. Bite marks on two gastralia were identified as belonging to Tarbosaurus, and it was proposed that this accounted for the scattered, disassociated state of the holotype specimen.[14]

In 2013, the discovery of two new Deinocheirus specimens was announced before the annual Society of Vertebrate Paleontology (SVP) conference by Lee, Barsbold, Currie, and colleagues. Housed at the Mongolian Academy of Sciences, these two headless individuals were given the specimen numbers MPC-D 100/127 and MPC-D 100/128. MPC-D 100/128, a subadult specimen, was found by scientists in the Altan Ula IV locality (coordinates: 43°36.091′N 100°27.066′E / 43.601517°N 100.451100°E) of the Nemegt Formation during the Korea-Mongolia International Dinosaur Expedition in 2006, but had already been damaged by fossil poachers. The second specimen, MPC-D 100/127, was found by scientists in the Bugiin Tsav locality (coordinates: 43°54.025′N 99°58.359′E / 43.900417°N 99.972650°E) in 2009. It is slightly larger than the holotype, and it could be clearly identified as Deinocheirus by its left forelimb, and therefore helped identify the earlier collected specimen as Deinocheirus. The specimen had also been excavated by poachers, who had removed the skull, hands and feet, but left behind a single toe bone. It had probably been looted after 2002, based on money left in the quarry.[1][8] Skulls, claw bones and teeth are often selectively targeted by poachers on the expense of the rest of the skeletons (which are often vandalized), due to their saleability.[16] Currie stated in an interview that it was a policy of their team to investigate quarries after they had been looted and recover anything of significance, and that finding any new Deinocheirus fossils was cause for celebration, even without the poached parts. A virtual model of Deinocheirus revealed at the SVP presentation brought applause from the crowd of attending palaeontologists, and Scottish palaeontologist Stephen L. Brusatte stated he had never been as surprised by a SVP talk, though new fossils are routinely presented at the conference.[17]

Deinocheirus Skull
Skull cast of specimen MPC-D 100/127 on exhibit in Munich

After the new specimens were announced, it was rumoured that a looted skull had found its way to a European museum through the black market.[17] The poached elements were spotted in a private European collection by the French fossil trader François Escuillé, who notified Belgian palaeontologist Pascal Godefroit about them in 2011. They suspected the remains belonged to Deinocheirus, and contacted the Korean-Mongolian team. Escuillé subsequently acquired the fossils and donated them to the Royal Belgian Institute of Natural Sciences.[18] The recovered material consisted of a skull, a left hand, and feet, which had been collected in Mongolia, sold to a Japanese buyer, and resold to a German party. The team concluded that these elements belonged to specimen MPC-D 100/127, as the single leftover toe bone fit perfectly into the unprepared matrix of a poached foot, the bone and matrix matched in colour, and because the elements belonged to an individual of the same size, with no overlap in skeletal elements.[1] On May 1, 2014, the fossils were repatriated to Mongolia by a delegation from the Belgian Museum, during a ceremony held at the Mongolian Academy of Sciences.[19] The reunited skeleton was deposited at the Central Museum of Mongolian Dinosaurs in Ulaanbaatar, along with a Tarbosaurus skeleton which had also been brought back after being stolen. American palaeontologist Thomas R. Holtz stated in an interview that the new Deinocheirus remains looked like the "product of a secret love affair between a hadrosaur and Gallimimus".[18]

Combined with the poached elements, both new specimens represent almost the entire skeleton of Deinocheirus, as MPC-D 100/127 includes all material apart from the middle dorsal vertebrae, most caudal vertebrae, and the right forelimb; MPC-D 100/128 fills in most gaps of the other skeleton, with nearly all dorsal and caudal vertebrae, the ilium, a partial ischium, and most of the left hindlimb. In 2014, the specimens were described in the Nature journal by Lee, Barsbold, Currie, Yoshitsugu Kobayashi, Hang-Jae Lee Lee, Godefroit, Escuillié, and Tsogtbaatar Chinzorig.[1] A similar series of events was reported earlier in 2014 with Spinosaurus, another sail-backed theropod which had only been known from few remains since 1912. Poached remains were reunited with specimens obtained by scientists, and Spinosaurus was shown to have been quite different from other spinosaurids. The two cases showed that the lifestyle and appearance of incompletely known extinct animals cannot always be safely inferred from close relatives.[9] By 2017, the Mongolian government had increased its effort to seize poached fossils from collectors and repatriate them, but proving their provenance had become a scientific and political concern. Therefore, a study tested the possibility of identifying poached fossils by geochemical methods, using Deinocheirus and other Nemegt dinosaurs as examples.[16]

Classification

Skeleton of Beishanlong grandis
Restored skeleton of the closely related species Beishanlong grandis
Deinocheirus hand front view
Front view of a Deinocheirus arm cast, Japan

When Deinocheirus was only known from the original forelimbs, its taxonomic relationship was difficult to determine, and several hypotheses were proposed.[9] Osmólska and Roniewicz initially concluded that Deinocheirus did not belong in any already named theropod family, so they created a new, monotypic family Deinocheiridae, placed in the infraorder Carnosauria. This was due to the large size and thick-walled limb bones, but they also found some similarities with Ornithomimus, and, to a lesser extent, Allosaurus.[6] In 1971, John Ostrom first proposed that Deinocheirus belonged with the Ornithomimosauria, while noting that it contained both ornithomimosaurian and non-ornithomimosaurian characters.[1][9] In 1976, Rhinchen Barsbold named the order Deinocheirosauria, which was to include the supposedly related genera Deinocheirus and Therizinosaurus. A relationship between Deinocheirus and the long-armed therizinosaurs was supported by some later writers, but they are not considered to be closely related today.[13]

In 2004, Peter Makovicky, Kobayashi and Currie pointed out that Deinocheirus was likely a primitive ornithomimosaurian, since it lacked some of the features typical of the Ornithomimidae family.[20] Primitive traits include its recurved claws, the low humerus-to-scapula ratio, and the lack of a syndesmosis. A 2006 study by Kobayashi and Barsbold found Deinocheirus to be possibly the most primitive ornithomimosaur, but was unable to further resolve its affinities, due to the lack of skull and hindlimb elements.[13] A cladistic analysis accompanying the 2014 description of the two much more complete specimens found that Deinocheirus formed a clade with Garudimimus and Beishanlong, which were therefore included in the Deinocheiridae. The resulting cladogram follows below:[1]

Ornithomimosauria

Nqwebasaurus

unnamed

Pelecanimimus

unnamed

Shenzhousaurus

unnamed

Harpymimus

unnamed
Deinocheiridae

Beishanlong

unnamed

Garudimimus

Deinocheirus

Ornithomimidae

Anserimimus

unnamed

Gallimimus

unnamed

Ornithomimus

Struthiomimus

The 2014 study defined Deinocheiridae as a clade including all taxa with a more recent common ancestor with Deinocheirus mirificus than with Ornithomimus velox. The three members share various anatomical features in the limbs. The 2014 cladogram suggested that ornithomimosaurians diverged into two major lineages in the Early Cretaceous; Deinocheiridae and Ornithomimidae. Unlike other ornithomimosaurians, deinocheirids were not built for running. The anatomical peculiarities of Deinocheirus when compared to other, much smaller ornithomimosaurs, can largely be explained by its much larger size and weight.[1] Deinocheirids and the smaller ornithomimids did not have teeth, unlike more primitive ornithomimosaurs.[9]

Paleobiology

Deinocheirus NT
Life restoration

The blunt and short claws of Deinocheirus are similar to those of the therizinosaur Alxasaurus, which indicates the long arms and claws were used for digging and gathering plants. The blunt claws of the feet could have helped the animal from sinking into substrate when wading. The robust hind limbs and hip region indicates the animal moved slowly. The large size of the animal may have helped it against predators such as Tarbosaurus, but in turn it lost the running ability of other ornithomimosaurs. The long neural spines and possible tail fan may have been used for display behaviour. Deinocheirus was likely diurnal (active during the day), since the sclerotic rings of the eyes were relatively small in comparison with its skull length.[1] The hand had good mobility relative to the lower arm, but was capable of only a limited flexing motion, unable to close in grasping.[6]

The brain of Deinocheirus was reconstructed through CT scans and presented at the 2014 Society of Vertebrate Palaeontology conference. The brain was globular and similar in shape to that of birds and troodontid theropods, the cerebrum was expanded in a way similar to most theropods, and the olfactory tracts were relatively large. The brain was proportionally small and compact, and its Reptile Encephalisation Quotient (brain-body ratio) was estimated at 0.69, which is low for theropods, and similar to sauropods. Other ornithomimosaurs have proportionally large brains, and the small brain of Deinocheirus may reflect its social behaviour or diet. Its coordination and balance would not have been as important as for carnivorous theropods.[21] A bone microstructure study presented at the 13th Annual Meeting of the European Association of Vertebrate Palaeontologists in 2015 showed that Deinocheirus probably had a high metabolic rate, and grew rapidly before reaching sexual maturity.[22] In 2015, Akinobu Watanabe and colleagues found that together with Archaeornithomimus and Gallimimus, Deinocheirus had the most pneumatised skeleton among ornithomimosaurs. Pneumatisation is thought to be advantageous for flight in modern birds, but its function in non-avian dinosaurs is not known with certainty. It has been proposed that pneumatisation was used to reduce the mass of large bones (associated with gigantic size in the case of Deinocheirus), that it was related to high metabolism, balance during locomotion, or used for thermoregulation.[10]

Diet

Deinocheirus
Reconstructed cast of the holotype arms in Museum of Natural History, London

The distinct shape of the skull shows that Deinocheirus had a more specialised diet than other ornithomimosaurs. The beak was similar to that of ducks, which indicates it may have likewise foraged in water, or browsed near the ground like some sauropods and hadrosaurs. The attachment sites for the muscles that open and close the jaws were very small in comparison to the size of the skull, which indicates Deinocheirus had a weak bite force. The skull was likely adapted for cropping soft understorey or water vegetation. The depth of the lower jaw indicates the presence of a large tongue, which could have assisted the animal in sucking in food material obtained with the broad beak when foraging on the bottom of freshwater bodies.[1]

More than 1,400 gastroliths (stomach stones, 8 to 87mm in size) were found among the ribs and gastralia of specimen MPC-D100/127. The ratio of gastrolith mass to total weight, 0.0022, supports the theory that these gastroliths helped the toothless animals in grinding their food. Features such as the presence of a beak and a U-shaped, downturned jaw, are indicators of facultative (optional) herbivory among coelurosaurian theropods. In spite of these features, fish vertebrae and scales were also found among the gastroliths, which suggests that it was an omnivore.[1] Ornithomimosaurs in general are thought to have fed on both plants and small animals.[9]

Deinocheirus claw
Cast of a claw in Japan, showing its blunt, recurved shape

Various feeding behaviours were proposed before more complete remains of Deinocheirus were known, and it was early on envisioned as a predatory, allosaur-like animal with giant arms.[9] In their original description, Osmólska and Roniewicz found that the hands of Deinocheirus were unsuited for grasping, but could instead have been used to tear prey apart.[6] In 1970, the Russian paleontologist Anatoly Konstantinovich Rozhdestvensky compared the forelimbs of Deinocheirus to sloths, leading him to hypothesise that Deinocheirus was a specialised climbing dinosaur, that fed on plants and animals found in trees.[23] In 1988, Gregory S. Paul instead suggested that the claws were too blunt for predatory purposes, but would have been good defensive weapons.[5] While attempting to determine the ecological niches for Deinocheirus and Therizinosaurus in 2010, Phil Senter and James H. Robins suggested that Deinocheirus had the largest vertical feeding range due to its hip height, and specialised in eating high foliage.[2] In 2017, it was suggested that the claws of Deinocheirus were adapted for pulling large quantities of herbaceous plants out of water, and to decrease the resistance of water.[24]

Palaeopathology

Osmólska and Roniewicz reported that the holotype specimen has abnormal pits, grooves and tubercles on the first and second phalanx of the left second finger that may be the result of injuries to the joint between the two bones. The damage may have caused changes to the arrangement of ligaments of muscles. The two coracoids are also differently developed.[6][25] A rib of specimen MPC-D 100/127 shows a healed trauma which has remodelled the bone.[1] In 2012, bite marks on two gastralia of the holotype specimen were reported. The size and shape of the bite marks match the teeth of Tarbosaurus, the largest known predator from the Nemegt Formation. Various types of feeding traces were identified; punctures, gouges, striae, fragmentary teeth, and combinations of the above marks. The bite marks probably represent feeding behaviour instead of aggression between the species, and the fact that bite marks were not found elsewhere on the body indicates the predator focused on internal organs. Tarbosaurus bite marks have also been identified on hadrosaur and sauropod fossils, but theropod bite marks on bones of other theropods are very rare in the fossil record.[14]

Palaeocology

A View of the Delta
The Okavango Delta, which is similar to the environment Deinocheirus inhabited

The three known Deinocheirus specimens were recovered from the Nemegt Formation in the Gobi Desert of southern Mongolia. This geologic formation has never been dated radiometrically, but the fauna present in the fossil record indicate it was probably deposited during the early Maastrichtian stage, at the end of the Late Cretaceous about 70 million years ago.[26][27][28] The rock facies of the Nemegt Formation suggest the presence of stream and river channels, mudflats, and shallow lakes. Such large river channels and soil deposits are evidence of a far more humid climate than those found in the older Barun Goyot and Djadochta formations. However, caliche deposits indicate at least periodic droughts occurred. Sediment was deposited in the channels and floodplains of large rivers.[29]

Tarbosaurus and Deinocheirus
Restoration of two Tarbosaurus attacking a Deinocheirus

Deinocheirus is thought to have been widely distributed within the Nemegt Formation, as the only three specimens found have been 50 km (31 mi) apart. The river systems of the Nemegt Formation provided a suitable niche for Deinocheirus with its omnivorous habits.[1] The environment was similar to the Okavango Delta of present-day Botswana. Within this ecosystem, Deinocheirus would have eaten plants and small animals, including fish. It may have competed for trees with other large herbivorous dinosaurs such as the long-necked theropod Therizinosaurus, various titanosaurian sauropods, and the smaller hadrosaurid Saurolophus. Deinocheirus may have competed with those herbivores for higher foliage such as trees, but was also able to feed on material that they could not. Along with Deinocheirus, the discoveries of Therizinosaurus and Gigantoraptor show that three groups of herbivorous theropods (ornithomimosaurs, therizinosaurs and oviraptorosaurs), independently reached their maximum sizes in the late Cretaceous of Asia.[9]

The habitats in and around the Nemegt rivers where Deinocheirus lived provided a home for a wide array of organisms. Occasional mollusc fossils are found, as well as a variety of other aquatic animals like fish and turtles, and the crocodylomorph Shamosuchus.[26][30] Mammal fossils are rare in the Nemegt Formation, but many birds have been found, including the enantiornithine Gurilynia, the hesperornithiform Judinornis, as well as Teviornis, a possible Anseriform. Herbivorous dinosaurs of the Nemegt Formation include ankylosaurids such as Tarchia, the pachycephalosaurian Prenocephale, large hadrosaurids such as Saurolophus and Barsboldia, and sauropods such as Nemegtosaurus, and Opisthocoelicaudia.[26][31] Predatory theropods that may have lived alongside Deinocheirus include tyrannosauroids such as Tarbosaurus, Alioramus, and Bagaraatan, and troodontids such as Borogovia, Tochisaurus, and Zanabazar. Theropod groups with both omnivorous and herbivorous members include therizinosaurs, such as Therizinosaurus, oviraptorosaurians, such as Elmisaurus, Nemegtomaia, and Rinchenia, and other ornithomimosaurians, such as Anserimimus and Gallimimus.[32]

See also

References

  1. ^ a b c d e f g h i j k l m n o p q r s Lee, Y.N.; Barsbold, R.; Currie, P.J.; Kobayashi, Y.; Lee, H.J.; Godefroit, P.; Escuillié, F.O.; Chinzorig, T. (2014). "Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus". Nature. 515 (7526): 257–260. Bibcode:2014Natur.515..257L. doi:10.1038/nature13874. PMID 25337880.
  2. ^ a b c Senter, P.; Robins, J.H. (2010). "Hip heights of the gigantic theropod dinosaurs Deinocheirus mirificus and Therizinosaurus cheloniformis, and implications for museum mounting and paleoecology" (PDF). Bulletin of the Gunma Museum of Natural History (14): 1–10.
  3. ^ Paul, G.S. (2010). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 112. ISBN 978-0-691-13720-9.
  4. ^ Valkenburgh, B.V.; Molnar, R.E. (2002). "Dinosaurian and mammalian predators compared". Paleobiology. 28 (4): 530–540. doi:10.1666/0094-8373(2002)028<0527:dampc>2.0.co;2. JSTOR 3595499.
  5. ^ a b Paul, G.S. (1988). Predatory Dinosaurs of the World. Simon & Schuster. pp. 228, 382. ISBN 978-0-671-61946-6.
  6. ^ a b c d e f Osmólska, H.; Roniewicz, E. (1970). "Deinocheiridae, a new family of theropod dinosaurs" (PDF). Palaeontologica Polonica (21): 5–19.
  7. ^ Middleton, K.M.; Gatesy, S.M. (2000). "Theropod forelimb design and evolution". Zoological Journal of the Linnean Society. 128 (2): 160, 172. doi:10.1111/j.1096-3642.2000.tb00160.x.
  8. ^ a b Lee, Y.N.; Barsbold, R.; Currie, P.J.; Kobayashi, Y.; Lee, H.J. (2013). "New specimens of Deinocheirus mirificus from the Late Cretaceous of Mongolia" (PDF). Society of Vertebrate Paleontology Abstracts of Papers: 161. Archived from the original (PDF) on 2014-12-04.
  9. ^ a b c d e f g h i Holtz, T.R. (2014). "Paleontology: Mystery of the horrible hands solved". Nature. 515 (7526): 203–205. Bibcode:2014Natur.515..203H. doi:10.1038/nature13930. PMID 25337885.
  10. ^ a b Watanabe, A.; Eugenia Leone Gold, M.; Brusatte, S. L.; Benson, R. B. J.; Choiniere, J.; Davidson, A.; Norell, M. A.; Claessens, L. (2015). "Vertebral pneumaticity in the ornithomimosaur Archaeornithomimus (Dinosauria: Theropoda) revealed by computed tomography imaging and reappraisal of axial pneumaticity in ornithomimosauria". PLOS One. 10 (12): e0145168. Bibcode:2015PLoSO..1045168W. doi:10.1371/journal.pone.0145168. PMID 26682888.
  11. ^ Kielan-Jaworowska, Z.; Dovchin, N. (1968). "Narrative of the Polish-Mongolian Palaeontological Expeditions 1963–1965" (PDF). Palaeontologica Polonica. 19: 24.
  12. ^ Dodson, P. (1998). The Horned Dinosaurs: A Natural History. Princeton University Press. p. 9. ISBN 978-0-691-05900-6.
  13. ^ a b c Kobayashi, Y.; Barsbold, R. (2006). "Ornithomimids from the Nemegt Formation of Mongolia" (PDF). Journal of the Paleontological Society of Korea. 22 (1): 195–207.
  14. ^ a b c Bell, P.R.; Currie, P.J.; Lee, Y.N. (2012). "Tyrannosaur feeding traces on Deinocheirus (Theropoda:?Ornithomimosauria) remains from the Nemegt Formation (Late Cretaceous), Mongolia". Cretaceous Research. 37: 186–190. doi:10.1016/j.cretres.2012.03.018.
  15. ^ "Cretaceous Mongolian Dinosaurs". DinoCasts.com. Archived from the original on February 2, 2015.
  16. ^ a b Fanti, F.; Bell, P. R.; Tighe, M.; Milan, L. A.; Dinelli, E. (2017). "Geochemical fingerprinting as a tool for repatriating poached dinosaur fossils in Mongolia: A case study for the Nemegt Locality, Gobi Desert". Palaeogeography, Palaeoclimatology, Palaeoecology. 494: 51–64. Bibcode:2018PPP...494...51F. doi:10.1016/j.palaeo.2017.10.032.
  17. ^ a b Switek, B. (November 4, 2013). "Mystery Dinosaur Finally Gets a Body". National Geographic Society.
  18. ^ a b Hecht, J. (May 12, 2014). "Stolen dinosaur head reveals weird hybrid species".
  19. ^ "The "horrible hand" Deinocheirus dinosaur's fossils are repatriated to its home country". InfoMongolia.com. Archived from the original on 2014-05-12.
  20. ^ Makovicky, P.J.; Kobayashi, Y.; Currie, P.J. (2004). "Ornithomimosauria". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (2 ed.). University of California Press. pp. 137–150. ISBN 978-0-520-24209-8.
  21. ^ Lauters, P.; Lee, Y.N.; Barsbold, R.; Currie, P.J.; Kobayashi, Y.; Escuillé, F.O.; Godefroit, P. (2014). "The brain of Deinocheirus mirificus, a gigantic ornithomimosaurian dinosaur from the Cretaceous of Mongolia" (PDF). Society of Vertebrate Paleontology Abstracts of Papers: 166. Archived from the original (PDF) on 2014-12-04.
  22. ^ Kundrát, M.; Lee, Y.N. (2015). "First insights into the bone microstructure of Deinocheirus mirificus" (PDF). 13th Annual Meeting of the European Association of Vertebrate Palaeontologists: 25. Archived from the original (PDF) on 2015-07-20. Retrieved 2015-07-17.
  23. ^ Rozhdestvensky, A.K. (1970). "Gigantskiye kogti zagadochnykh mezozoyskikh reptiliy" [Giant claws of enigmatic Mesozoic reptiles]. Paleontologicheskii Zhurnal (in Russian). 1970 (1): 117–125.
  24. ^ Chinzorig, T.; Kobayashi, Y.; Tsogtbaatar, K.; Currie, P. J.; Takasaki, R.; Tanaka, T.; Iijima, M.; Barsbold, R. (2017). "Ornithomimosaurs from the Nemegt Formation of Mongolia: manus morphological variation and diversity". Palaeogeography, Palaeoclimatology, Palaeoecology. 494: 91–100. Bibcode:2018PPP...494...91C. doi:10.1016/j.palaeo.2017.10.031.
  25. ^ Molnar, R.E. (2001). "Theropod Paleopathology: a Literature Survey". In Tanke, Darren H.; Carpenter, Kenneth (eds.). Mesozoic Vertebrate Life. Indiana University Press. p. 343. ISBN 978-0-253-33907-2.
  26. ^ a b c Jerzykiewicz, T.; Russell, D.A. (1991). "Late Mesozoic stratigraphy and vertebrates of the Gobi Basin". Cretaceous Research. 12 (4): 345–377. doi:10.1016/0195-6671(91)90015-5.
  27. ^ Sullivan, R.M. (2006). "A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia)" (PDF). In Lucas, Spencer G.; Sullivan, Robert M. (eds.). Late Cretaceous vertebrates from the Western Interior. 35. New Mexico Museum of Natural History and Science Bulletin. pp. 347–366.
  28. ^ Gradstein, F.M.; Ogg, J.G.; Smith, A.G. (2005). A Geologic Time Scale 2004. Cambridge University Press. pp. 344–371. ISBN 978-0-521-78142-8.
  29. ^ Novacek, M. (1996). Dinosaurs of the Flaming Cliffs. Anchor. p. 133. ISBN 978-0-385-47775-8.
  30. ^ Efimov, M.B. (1983). "Peresmotr iskopayemykh krokodilov Mongolii" [Revision of the fossil crocodiles of Mongolia]. Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya Trudy (in Russian). 24: 76–96.
  31. ^ Hurum, J.H.; Sabath, K. (2003). "Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared" (PDF). Acta Palaeontologica Polonica. 48 (2): 188.
  32. ^ Holtz, T.R. (2004). "Tyrannosauroidea". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (2 ed.). University of California Press. p. 124. ISBN 978-0-520-24209-8.

External links

1970 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1970.

Air sac

Air sacs are spaces within an organism where there is the constant presence of air. Among modern animals, birds possess the most air sacs (9–11), with their extinct dinosaurian relatives showing a great increase in the pneumatization (presence of air) in their bones. Theropods, like Aerosteon, have many air sacs in the body that are not just in bones, and they can be identified as the more primitive form of modern bird airways. Sauropods are well known for the amount of air pockets in their bones (especially vertebra), although one theropod, Deinocheirus, shows a rivalling amount of air pockets.

Anserimimus

Anserimimus( AN-sər-i-MY-məs; "goose mimic") is a genus of ornithomimid theropod dinosaur, from the Late Cretaceous Period of what is now Mongolia. It was a lanky, fast-running animal, possibly an omnivore. From what fossils are known, it probably closely resembled other ornithomimids, except for its more powerful forelimbs.

Beishanlong

Beishanlong is a genus of giant ornithomimosaurian theropod dinosaur from the Early Cretaceous of China.

Deinocheiridae

Deinocheiridae is a family of ornithomimosaurian dinosaurs, living in Asia from the Albian until the Maastrichtian. The family was originally named by Halszka Osmólska and Roniewicz in 1970, including only the type genus Deinocheirus. In a 2014 study by Yuong-Nam Lee and colleagues and published in the journal Nature, it was found that Deinocheiridae was a valid family. Lee et al. found that based on a new phylogenetic analysis including the recently discovered complete skeletons of Deinocheirus, the type genus, as well as Garudimimus and Beishanlong, could be placed as a successive group, with Beishanlong as the most primitive and Deinocheirus as most derived. The family Garudimimidae, named in 1981 by Rinchen Barsbold, is now a junior synonym of Deinocheiridae as the latter family includes the type genus of the former. The group existed from 115 to 69 million years ago, with Beishanlong living from 115 to 100 mya, Garudimimus living from 98 to 83 mya, and Deinocheirus living from 71 to 69 mya.

Gallimimus

Gallimimus ( GAL-i-MY-məs) is a genus of theropod dinosaur that lived in what is now Mongolia during the Late Cretaceous period, about 70 million years ago (mya). Gallimimus is the largest known ornithomimid; adults were about 6 metres (20 ft) long, 1.9 metres (6 ft 3 in) tall at the hip and weighed about 440 kilograms (970 lb). As evidenced by its relative Ornithomimus, it would have had feathers. The head was small and light with large eyes that faced to the sides. The snout was long compared to other ornithomimids, although it was broader and more rounded at the tip than in other species. Gallimimus was toothless with a keratinous (horny) beak, and had a delicate lower jaw. Many of the vertebrae had openings that indicate they were pneumatic (air-filled). The neck was proportionally long in relation to the trunk. The hands were proportionally the shortest of any ornithomimosaur and each had three digits with curved claws. The forelimbs were weak while the hindlimbs were proportionally long.

Several fossils in various stages of growth were discovered by Polish-Mongolian expeditions in the Gobi Desert of Mongolia during the 1960s; a large skeleton discovered in this region was made the holotype specimen of the new genus and species Gallimimus bullatus in 1972. The generic name means "chicken mimic", referring to the similarities between its neck vertebrae and those of the Galliformes. The specific name is derived from bulla, a gold capsule worn by Roman youth, in reference to a bulbous structure at the base of the skull of Gallimimus. At the time it was named, the fossils of Gallimimus represented the most complete and best preserved ornithomimid material yet discovered, and the genus remains one of the best known members of the group. The family Ornithomimidae is part of the group Ornithomimosauria, the "ostrich dinosaurs". Anserimimus, also from Mongolia, is thought to have been the closest relative of Gallimimus.

As an ornithomimid, Gallimimus would have been a fleet (or cursorial) animal, using its speed to escape predators; its speed has been estimated at 42-56 km/h (29-34 mph). It may have had good vision and intelligence comparable to ratite birds. Gallimimus may have lived in groups, based on the discovery of several specimens preserved in a bone bed. Various theories have been proposed regarding the diet of Gallimimus and other ornithomimids. The highly mobile neck may have helped locate small prey on the ground, but it may also have been an opportunistic omnivore. It has also been suggested that it used small columnar structures in its beak for filter-feeding in water, though these structures may instead have been ridges used for feeding on tough plant material, indicative of a herbivorous diet. Gallimimus is the most commonly found ornithomimosaur in the Nemegt Formation, where it lived alongside its relatives Anserimimus and Deinocheirus. Gallimimus was featured in the movie Jurassic Park, in a scene that was important to the history of special effects, and in shaping the common conception of dinosaurs as bird-like animals.

Garudimimus

Garudimimus ("Garuda mimic") is a basal ornithomimosaurian theropod dinosaur from the Upper Cretaceous of Mongolia.

Halszka Osmólska

Halszka Osmólska (September 15, 1930 – March 31, 2008) was a Polish paleontologist who had specialized in Mongolian dinosaurs.

List of commonly used taxonomic affixes

This is a list of common affixes used when scientifically naming species, particularly extinct species for whom only their scientific names are used, along with their derivations.

-acanth, acantho-, -cantho: Pronunciation: /eɪkænθ/, /eɪkænθoʊ/. Origin: Ancient Greek ἄκανθα (ákantha). Meaning: spine.Examples: Acanthodes ("spiny base"); Acanthostega ("spine roof"); coelacanth ("hollow spine") Acrocanthosaurus ("high-spined lizard")arch-, archi-, archo-, -archus: Pronunciation: /ark/, /arkoʊ/, /arkɪ/, /arkəs/. Origin: Ancient Greek ἀρχός (arkhós), meaning: ruler; ἀρχικός (arkhikós), meaning: ruling. Used for exceptionally large or widespread animals.Examples: Archelon ("ruling turtle"); Architeuthis ("ruling squid"); Archosaur ("ruling lizard"); Andrewsarchus ("Andrews's ruler")archaeo-: Pronunciation: /arkiːɒ/, /arkiːoʊ/ . Origin: Ancient Greek ἀρχαῖος (arkhaîos). Meaning: ancient. Used for early versions of animals and plants.Examples: Archaeopteryx ("ancient wing"); Archaeoindris ("ancient Indri"); Archaeopteris ("ancient fern")arthro-: /arθroʊ/. Origin: Ancient Greek ἄρθρον (árthron). Meaning: Joint. Often used for animals with exoskeletons.Examples: Arthrospira ("jointed coil"); Arthropleura ("jointed rib"); arthropod ("jointed foot")-aspis: Pronunciation: /əspɪs/. Origin: Ancient Greek ἀσπίς (aspís). Meaning: Shield. Used to describe armored fish.Examples: Cephalaspis ("head shield"); Sacabambaspis ("Sacabamba shield"); Brindabellaspis ("Brindabella shield")-avis: Pronunciation: /əvɪs/. Origin: Latin avis. Meaning: Bird.Examples: Protoavis ("first bird"); Argentavis ("Argentine bird"); Eoalulavis ("little-winged dawn bird")brachi-, brachy-: pronunciation: /brækɪ/. Origin: Ancient Greek βραχύς, βραχίων (brakhús, brakhíōn). Meaning: short, and the short part of the arm, or upper arm, respectively. Used in its original meaning, and also to mean "arm".Examples: Brachylophosaurus ("short-crested lizard"); Brachiosaurus ("arm lizard"); Brachyceratops ("short-horned face")bronto-: Pronunciation: /brɒntoʊ/. Origin: Ancient Greek βροντή (brontḗ). Meaning: thunder. Used for large animals.Examples: Brontosaurus ("thunder lizard"), Brontotherium ("thunder beast"), Brontoscorpio ("thunder scorpion")-canth, cantho-: see -acanth, acantho-

-cephalus, cephalo-, -cephale, -cephalian: Pronunciation: /sɛfələs/, /sɛfəloʊ̯/, /sɛfəli:/ /sɛfeɪliːən/. Origin: Ancient Greek κεφαλή (kephalḗ). Meaning: head.Examples: Euoplocephalus ("well-protected head"), Pachycephalosaurus ("thick headed lizard"), Amtocephale ("Amtgai head"); Therocephalian ("beast-headed")-ceras, cerat-, -ceratus, -cerato, : Pronunciation: /sɛrəs/, /sɛrət/. Origin: Ancient Greek κέρας (kéras). Meaning: horn. Used for many horned animals, but most notably ceratopsians.Examples: Triceratops ("three-horned face"), Orthoceras ("straight horn") Megaloceras ("big horn") Ceratosaurus ("horned lizard") Microceratus ("small horned")cetio-, -cetus: Pronuncuation: /sɛtɪoʊ/, /siːtəs/. Origin: Ancient Greek κῆτος (kētos). Meaning: sea-monster. The suffix "-cetus" is used for whales or whale ancestors, while the prefix "cetio-" is used for whale-like or large animals.Examples: Cetiosaurus ("whale lizard"); Ambulocetus ("walking whale"); Pakicetus ("Pakistan whale")-cheirus: Pronunciation: /kaɪrəs/. Origin: χείρ (kheír). Meaning: hand.Examples: Deinocheirus ("terrible hand"); Ornithocheirus ("bird hand"); Austrocheirus ("southern hand") Haplocheirus ("simple hand")chloro-: Pronunciation: /kloroʊ/. Origin: Ancient Greek χλωρός (khlōrós). Meaning": green.Examples: Chlorophyta ("green plant") Chlorophyll (¨green leaf¨)coel-: Pronunciation: /siːl/ or /sɛl/ . Origin: Ancient Greek κοῖλος (koîlos). Meaning: hollow.Examples: coelacanth ("hollow spine"); Coelodonta ("hollow tooth"); Coelophysis ("hollow form") Amphicoelias (¨hollow at both ends¨)cyclo-: Pronunciation: /saɪkləʊ/ (or /saɪklɒ/). Origin: Ancient Greek κύκλος (kúklos). Meaning: circle.Examples: Cyclomedusa ("circle Medusa"); Cyclostomata ("circle mouth")cyn-, -cyon: Pronunciation: /saɪn/, /saɪɒn/. Origin: Ancient Greek κύων (kúon). Meaning: dog. Used for dogs or dog-like creatures.Examples: Cynodont ("dog tooth"); Cynopterus ("dog wing"); Arctocyon ("bear dog")-dactyl, -dactylus: Pronunciation: /dæktəl/, /dæktələs/. Origin: Ancient Greek δάκτυλος (dáktulos). Meaning: finger, toe.Examples: artiodactyl ("even toe"); Pterodactylus ("wing finger"); perissodactyl ("uneven toe")-derm: Pronunciation: /dɜrm/. Origin: Ancient Greek δέρμα (dérma). Meaning: animal hide. Used for skin.Examples: placoderm ("plated skin"); echinoderm ("hedgehog skin"); ostracoderm ("shell skin")deino-: See dino-, deino-.

dendro-, -dendron, -dendrum: Pronunciation: /dɛn.dɹoʊ/, /ˈdɛndɹən/, /dɛndɹəm/. Origin: Ancient Greek δένδρον (déndron). Meaning: tree.Examples: Rhododendron ("rose tree"); Liriodendron ("lily tree"); Dendrocnide ("tree nettle"); Epidendrum ("above tree") Lepidodendron (¨scaled tree¨)di-: Pronunciation: /daɪ/. Origin: Ancient Greek δίς (dís). Meaning: twice. Used to indicate two of something.Examples: Dilophosaurus ("twice crested lizard"); Diceratops ("two-horned face") diapsid ("two arches")dino-, deino-: Pronunciation: /daɪnoʊ/. Origin: Ancient Greek δεινός (deinós). Meaning: "terrible", "formidable". Used for presumably fearfully large or dangerous animals or animal parts.Examples: dinosaur ("terrible lizard"), Dinofelis ("terrible cat"), Deinonychus ("terrible claw"), Deinocheirus ("terrible hand")diplo-: Pronunciation: /dɪploʊ/, /dɪplo/. Origin: Ancient Greek διπλόος, διπλοῦς (diplóos, diploûs). Meaning: double.Examples: Diplodocus ("double beam"); Diplopoda ("double feet"); Diplomonad ("double unit")-don, -dont, -donto-: See -odon, -odont, -odonto-.

dromaeo-, -dromeus: Pronunciation: /droʊmɪoʊ/, /droʊmɪəs/ Origin: Ancient Greek δρομαῖος (dromaîos). Meaning: runner.Examples: Dromaeosaurus ("runner lizard"); Kulindadromeus ("Kulinda runner"); Thalassodromeus ("sea runner")eo-: Pronunciation: /iːoʊ̯/. Origin: Ancient Greek ἠώς (ēṓs). Meaning: dawn. Used for very early appearances of animals in the fossil record.Examples: Eohippus ("dawn horse"); Eomaia ("dawn Maia"); Eoraptor ("dawn seizer")-erpeton: Pronunciation: /ɜrpətɒn/. Origin: Ancient Greek ἑρπετόν (herpetón). Meaning: reptile (literally, "creeping thing"); used for amphibians.Examples: Hynerpeton ("Hyner creeper"); Greererpeton ("Greer creeper"); Arizonerpeton ("Arizona creeper")eu-: Pronunciation: /iːu̟/. Origin: Ancient Greek εὖ (eû). Meaning: "good", "well"; also extended via New Latin to mean "true". Used in a variety of ways, often to indicate well-preserved specimens, well-developed bones, "truer" examples of fossil forms, or simply admiration on the part of the discoverer.Examples: Euparkeria ("Parker's good [animal]") Euhelopus ("good marsh foot") Eustreptospondylus ("true Streptospondylus")-felis: Pronunciation: /fiːlɪs/. Origin: Latin felis, feles. Meaning: cat. "Felis" alone is the genus name for the group that includes the domestic cat.Examples: Dinofelis ("terrible cat"); Pardofelis ("leopard cat");-form, -formes: Pronunciation: /foʊrm/, /foʊrms/. Origin: Latin forma. Meaning: shape, form. Used for large groups of animals that share similar characteristics.Examples: galliformes ("chicken form"); anseriformes ("goose form"); Squaliformes ("shark form")giga-, giganto-: Pronunciation: /d͡ʒaɪgə/, /d͡ʒaɪgæntoʊ/. Origin: Ancient Greek γίγας, γῐ́γᾰντος (gígas, gigantos). Meaning: giant, of a giant, respectively. Used for large species.Examples: Giganotosaurus ("giant southern lizard"); Gigantopithecus ("giant ape"); Gigantoraptor ("giant seizer")-gnath-, gnatho-, -gnathus: Pronunciation: /neɪθ/, /neɪθoʊ/, /neɪθəs/ (or /gneɪθəs/). Origin: Ancient Greek γνάθος (gnáthos). Meaning: jaw.Examples: Caenagnathasia ("recent Asian jaw"); gnathostoma ("jaw mouth"); Compsognathus ("elegant jaw")hemi-: Pronunciation: /hɛmi/. Origin: Ancient Greek ἡμι- (hēmi-). Meaning: half.Examples: Hemicyon ("half-dog"); hemichordate ("half-chordate"); Hemiptera ("half-wing"hippus, hippo-: Pronunciation: /ἵππος/. Origin: Ancient Greek ἵππος (híppos). Meaning: horseExamples: Eohippus ("dawn horse"); Hippodraco ("horse dragon"); Hippopotamus ("river horse")hyl-, hylo-: Pronunciation: /haɪl/, /haɪloʊ/ (or /haɪlɒ/). Origin: Ancient Greek ὕλη ("húlē"). Meaning: wood, forest.Examples: Hylonomus ("forest dweller"); Hylobates ("forest walker"); Hylarana ("forest frog")-ia: Pronunciation: /iːə/. Origin: Ancient Greek -ια, -εια (-ia, -eia). Meaning: an abstraction usually used as an honorific for a person or place.Examples: Dickinsonia ("for Dickinson"); Cooksonia ("for Cookson"); Coloradia ("for Colorado") Edmontonia ("for Edmonton")ichthyo-, -ichthys: Pronunciation: /ɪkθioʊs/, /ɪkθis/. Origin: Ancient Greek ἰχθῦς (ikhthûs). Meaning: fish. The suffix "-ichthys" is used for fish, while the prefix "ichthyo-", while used for fish, is also used for fish-like creatures.Examples: Ichthyosaurus ("fish lizard"); Leedsichthys ("Leeds's fish"); Haikouichthys ("Haikou fish")-lania, Pronunciation: /læniːə/, Origin: Ancient Greek ἀλαίνειν (alaínein): Meaning: to wander. Used for animals that are found in most places around continents.Examples: Meiolania ("weak wanderer"); Megalania ("great wanderer")-lepis, lepido-: Pronunciation: /lɛpɪs/ /lɛpɪdoʊ/ (or /lɛpɪdɒ/). Origin: Ancient Greek λεπίς (lepís). Meaning: scale.Examples: Mongolepis ("Mongol scale"); Polymerolepis ("many part scale"); Lepidosauria ("scaled lizards"); Lepidoptera ("scaled wing"); Lepidodendron ("scaled tree")-lestes: Pronunciation: /lɛstiːz/. Origin: Ancient Greek λῃστής (lēistḗs). Meaning: robber.Examples: Carpolestes ("fruit robber"); Ornitholestes ("bird robber"); Sarcolestes ("flesh robber") Necrolestes ("grave robber")long: Pronunciation: /lʊng/. Origin: Mandarin long (龙/龍). Meaning: dragon. Used for dinosaur finds in ChinaExamples: Mei long ("sleeping dragon"); Bolong ("small dragon"); Zuolong ("Zuo's dragon")-lopho-, -lophus: Pronunciation: /lɒfoʊ/, /ləfəs/. Origin: Ancient Greek λόφος (lóphos). Meaning: A bird's crest. Used for animals with crests on their heads.Examples: Dilophosaurus ("two-crested lizard"); Brachylophosaurus ("short-crested lizard"); Saurolophus ("lizard crest")macro-: Pronunciation: /mækroʊ/. Origin: Ancient Greek μακρός (makrós). Meaning: (correctly) long; (usually) large.Examples: macropod ("big foot"); Macrodontophion ("big tooth snake"); Macrogryphosaurus ("big enigmatic lizard")-maia, maia-: Pronunciation: /meiə/ Origin: Ancient Greek Μαῖα (Maîa). Meaning: Originally the mother of Hermes in Greek mythology and the goddess of growth in Roman mythology, alternatively spelled Maja. Frequently used to indicate maternal roles, this word should not be construed as translating directly to "mother" (Latin māter; Ancient Greek μήτηρ mḗtēr); aside from being a proper name, in Ancient Greek "maîa" can translate to "midwife" or "foster mother" and was used as an honorific address for older women, typically translated into English as "Good Mother".Examples: Maiasaura ("Good Mother/Maia's lizard"); Eomaia ("dawn Maia"); Juramaia (Jurassic Maia")mega-, megalo-: Pronunciation: /mɛga/, /mɛgaloʊ̯/. Origin: Ancient Greek μέγας, μεγάλη (mégas, megálē). Meaning: big.Examples: Megarachne ("big spider"); Megalosaurus ("big lizard"); Megalodon ("big tooth")micro-: Pronunciation: /maɪkroʊ̯/. Origin: Ancient Greek μικρός (mikrós). Meaning: "small".Examples: Microraptor ("small seizer") Microvenator ("small hunter"); Microceratops ("small horned face")mimo-, -mimus: /maɪmoʊ̯/, /maɪməs/. Origin: Latin mimus. Meaning: actor. Used for creatures that resemble others.Examples: Struthiomimus; ("ostrich mimic"); Ornithomimus ("bird mimic"); Gallimimus ("chicken mimic"); ornithomimosaur ("bird mimic lizard")-monas, -monad: Pronunciation: /moʊnas/, /monas/, /moʊnad/, /monad/. Origin: Ancient Greek μονάς (monás). Meaning: unit. Used for single-celled organisms (mainly protists).Examples: Chlamydomonas ("cloak unit"); Pseudomonas ("false unit"); Metamonad ("encompassing unit")-morph: Pronunciation: /moʊrf/. Origin: Ancient Greek μορφή (morphḗ). Meaning: form, shape. Used for large groups of animals which share a common genetic lineageExamples: crocodylomorphs ("crocodile form"); sauropodomorphs ("sauropod form"); Muscomorpha ("fly form") Dimorphodon ("two forms of teeth")-nax, -anax-: Pronunciation: /ναξ/άναξ/. Origin: Ancient Greek ἄναξ (ánax). Meaning: king.Examples: Lythronax ("gore king") Saurophaganax ("king of the lizard-eaters")-nych, nycho-, -nyx: see -onych, onycho-, -onyx

-odon, -odont, -odonto-: Pronunciation: /oʊdɒn/, /oʊdɒnt/, /oʊdɒntoʊ/. Origin: Ancient Greek ὀδούς (odoús). Meaning: tooth.Examples: Dimetrodon ("two-measures of teeth"), cynodont ("dog tooth") Carcharodontosaurus ("serrated tooth lizard")-oides, -odes: Pronunciation: /oiːdiːz/, /oʊːdiːz/. Origin: Ancient Greek εἶδος (eîdos). Meaning: likeness. Used for species that resemble other species.Examples: Hypocnemoides ("like Hypocnemis"); Aetobarbakinoides ("like the long-legged buzzard"); Callianthemoides ("like Callianthemum"); Argyrodes ("like silver")onycho-, -onychus, -onyx: /ɒnikoʊ/, /ɒnikəs/ (or /ɒnaɪkoʊ/, ɒnaɪkəs/), /ɒniks/. Origin: Ancient Greek ὄνυξ (ónux). Meaning: claw.Examples: Deinonychus ("terrible claw"); Euronychodon ("European claw tooth"); Nothronychus ("sloth claw"), Baryonyx ("heavy claw")-ops: Pronunciation: /ɒps/. Origin: Ancient Greek ὄψ (óps). Meaning: face.Examples: Triceratops ("three-horned face"); Moschops ("calf face"); Spinops ("spine face")-ornis, ornith-, ornitho-: Pronunciation: /oʊ̯rnɪs/, /oʊ̯rnɪθ/, /oʊ̯rnɪθoʊ̯/. Origin: Ancient Greek ὄρνις, ὄρνιθος (órnis, órnithos). Meaning: bird, of a bird respectively. "ornith-" and "ornitho-" are generally used for animals with birdlike characteristics; the suffix "-ornis" is generally applied to fossil bird species.Examples: ornithischian ("bird-hipped"); Ornithocheirus ("bird-hand"); Eoconfuciusornis ("Confucius's dawn bird")pachy-: Pronunciation: /pæki/ Origin: Ancient Greek παχύς (pakhús). Meaning: thick.Examples: Pachycephalosaurus ("thick-headed lizard"); Pachylemur ("thick lemur"); Pachyuromys ("thick tailed mouse")para-: Pronunciation: /pærɑː/ Origin: Ancient Greek παρά (pará). Meaning: near. Used for species that resemble previously named species.Examples: Paranthodon ("near Anthodon"); Pararhabdodon ("near Rhabdodon"); Parasaurolophus ("near Saurolophus)"-pelta: Prnonucniation: /pɛltə:/ Origin: Ancient Greek πέλτη (péltē). Meaning: shield. Used for species with armor like a shield.Examples: Sauropelta ("lizard shield"); Dracopelta ("dragon shield")-pithecus: Pronunciation: /piθəkəs/. Origin: Ancient Greek πίθηκος (píthēkos). Meaning: ape.Examples: Australopithecus ("southern ape"); Ardipithecus ("floor ape"); Gigantopithecus ("giant ape")platy-: Pronunciation: /ˈplætɪ/. Origin: Ancient Greek πλατύς (platús). Meaning: flat. Used for creatures that are flat or have flat parts.Examples: Platyhelminthes ("flat worm"); Platybelodon ("flat spear-tusk"); Platycodon ("flat bell") Platypus ("flat foot)plesio-, plesi-: Pronunciation: /pliːziːoʊ/, /pliːz/ (or pliːʒ/). Origin: Ancient Greek πλησίον (plēsíon). Meaning: near. Used for species that bear similarities to other species.Examples: Plesiosaurus ("near lizard"); Plesiorycteropus ("near aardvark"); Plesiobaena ("near Baena"); Plesiadapis ("near Adapis")-pod, podo-, -pus: Pronunciation: /pɒd/, /pɒdoʊ/, /pʊs/. Origin: Ancient Greek πούς, ποδός (poús, podós). Meaning: foot, of the foot, respectively.Examples: Ornithopod ("bird foot"); Brachypodosaurus ("short footed lizard"); Moropus ("slow foot")pro-, protero-: pronunciation: /proʊ̯/, /proʊ̯tεroʊ̯/. Origin: Ancient Greek πρό, πρότερος (pró, próteros). Meaning: before. Usually used for ancestral forms.Examples:Proterosuchus ("before crocodile"); Procompsognathus ("before elegant jaw"); Prosaurolophus ("before lizard crest")proto-: Pronunciation: /proʊtoʊ/. Origin: Ancient Greek πρῶτος (prōtos). Meaning: first. Used for early appearances in the fossil record.Examples: Protoceratops ("first horned face"); Protognathosaurus ("first jaw lizard"); Protohadros ("first hadrosaur")psittaco-, -psitta: Pronunciation: /sitɑːkoʊ/, /psitə/. Origin: Ancient Greek ψιττακός (psittakós). Meaning: parrot. "Psittaco-" is used for parrot-like creatures, while the suffix "psitta" is used for parrots.Examples: Psittacosaurus ("parrot lizard"); Cyclopsitta ("Cyclops parrot"); Xenopsitta ("strange parrot").pter-, ptero-, -pterus, pteryg-, -ptera, -pteryx. Pronunciation: /ter/, /teroʊ/, /pterəs/, /terɪg/, /pterɪx/. Origin: Ancient Greek πτέρυξ, πτέρυγος (pterux, ptérugos). Meaning: wing, of a wing, respectively. Used for many winged creatures, but also expanded to mean "fin", and used for many undersea arthropods.Examples: Pteranodon ("toothless wing"); Pterodactylus ("winged finger"); Eurypterus ("wide wing" or fin); Pterygotus ("winged" or finned); Coleoptera ("sheathed wing"); Archaeopteryx ("ancient wing") Stenopterygius ("narrow finned")-pus: see: -pod, -podo-, -pus.-raptor, raptor-: Pronunciation: /ræptər/. Origin: Latin raptor. Meaning: "seizer, stealer". Frequently used for dromaeosaurids or similar animals. The term "raptor" by itself may also be used for a dromeosaurid, a Velociraptor, or originally, a bird of prey.Examples: Velociraptor ("swift seizer"); Utahraptor ("Utah seizer"); Raptorex ("seizer king")-rex: Pronunciation: /rεks/. Origin: Latin rex. Meaning: king. Often used for large or impressive animals.Examples: Raptorex ("seizer king"); Dracorex ("dragon king"); Tyrannosaurus rex ("tyrant lizard king")-rhina, rhino-, -rhinus: Pronunciation: /raɪnə/ /raɪnoʊ̯/, /raɪnəs/. Origin: Ancient Greek ῥίς (rhís). Meaning: nose.Examples: Altirhinus ("high nose"); Pachyrhinosaurus ("thick-nosed lizard"); Lycorhinus ("wolf nose"); Arrhinoceratops ("noseless horned face"); Cretoxyrhina ("Cretaceous sharp nose") Rhinoceros ("nose horn")rhodo-: Pronunciation: /roʊdoʊ/, /rodoʊ/. Origin: Ancient Greek ῥόδον (rhódon). Meaning: "rose". Used for red-colored organisms.Examples: Rhododendron ("rose tree"); Rhodophyta ("rose plant"); Rhodomonas ("rose unit")-rhynchus: Pronunciation: /rɪnkəs/. Origin: Ancient Greek ῥύγχος (rhúgkhos). Meaning: "beak", "snout".Examples: Rhamphorhynchus ("prow beak"); Aspidorhynchus ( "shield snout"); Ornithorhynchus ("bird beak")sarco-: Pronunciation: /sɑːrkʊ/. Origin: Ancient Greek σάρξ (sárx). Meaning: flesh. Used for flesh-eating animals or animals and plants with fleshy partsExamples: Sarcophilus ("flesh-loving"); Sarcopterygii ("fleshy fin"); Sarcosuchus ("flesh crocodile")saur, sauro-, -saurus: Pronunciation: /sɔər/, /sɔəroʊ/, /sɔərəs/. Origin: Ancient Greek σαῦρος (saûros). Meaning: lizard. Used for dinosaurs and other extinct reptiles.Examples: Dinosaur ("terrible lizard") Mosasaur ("Meuse lizard"), Tyrannosaurus ("tyrant lizard"), Allosaurus ("different lizard") Sauroposeidon ("Poseidon lizard")smilo-, -smilus: Pronunciation: /smaɪloʊ/, /smaɪləs/. Origin: Ancient Greek σμίλη (smílē). Meaning: a carving knife or chisel. Used for animals with sabre teeth.Examples: Smilodon ("knife tooth"); Smilosuchus ("knife crocodile"); Thylacosmilus ("pouched knife"); Xenosmilus ("strange knife")-spondylus: Pronunciation: /spɒndələs/. Origin: Ancient Greek σπόνδυλος (spóndulos). Meaning: vertebra.Examples:Streptospondylus ("backwards vertebra"); Massospondylus ("longer vertebra"); Bothriospondylus ("excavated vertebra")squali-, squalo-: Pronunciation: /skweɪlɪ/, /skweɪloʊ/ . Origin: Latin squalus. Meaning: a kind of sea fish. Used for shark like creatures.Examples:Squalodon ("shark tooth") Squaliformes ("shark form"); Squalicorax ("shark raven") Squalomorphii ("shark shape")stego-, -stega: Pronunciation: /stɛgoʊ/, /stɛgə/. Origin: Ancient Greek στέγη (stégē). Meaning: roof. Used for armoured or plated animals.Examples: Stegosaurus ("roofed lizard"); Ichthyostega ("roofed fish"); Acanthostega ("spine roof")strepto-: Pronunciation: /streptoʊ/, /strepto/. Origin: Ancient Greek στρεπτός (streptós). Meaning: twisted, bent.Examples: Streptophyta ("bent plant"); Streptococcus ("twisted granule"); Streptospondylus ("twisted vertebra")-stoma, -stome, -stomus: Pronunciation: /stoʊma/, /stoʊm/, /stoʊməs/. Origin: Ancient Greek στόμα (stóma). Meaning: mouth.Examples: deuterostome (second mouth); Gnathostoma ("jaw mouth") Anastomus ("on mouth")sucho-, -suchus: Pronunciation: /sjuːkoʊ/, /sjuːkəs/. Origin: Ancient Greek σοῦχος (soûkhos). Meaning:: Originally the Ancient Greek name for the Ancient Egyptian crocodile-headed god, Sobek. Used to denote crocodilians or crocodile-like animals.Examples: Deinosuchus ("terrible crocodile") Anatosuchus ("duck crocodile"), Suchomimus ("crocodile mimic")-teuthis: Pronunciation: /tjuːθɪs/. Origin: Ancient Greek τευθίς (teuthís). Meaning: squid. Used for squids and similar cephalopods.Examples: Gonioteuthis ("narrow squid") Architeuthis ("ruling squid") Vampyroteuthis ("vampire squid") Cylindroteuthis ("cylindrical squid")thero-, -therium. Pronunciation: /θɛroʊ/, /θiːrɪəm/. Origin: Ancient Greek θήρ (thḗr). Meaning: beast. Used for supposedly monstrous animals. The suffix "-therium" is often used to denote extinct mammals.Examples: theropod ("beast foot"), Megatherium ("big beast") Brontotherium ("thunder beast") Uintatherium ("beast of the Uinta mountains")thylac-: Pronunciation: /θaɪlæk/. Origin: Ancient Greek θύλακος (thúlakos). Meaning: a sack. In the sense of "pouch", used for marsupials.Examples: Thylacine ("pouched one"); Thylacoleo ("pouched lion"); Thylacosmilus ("pouched knife")tri-: Pronunciation: /traɪ/. Origin: Ancient Greek τρία (tría). Meaning: three.Examples: Triceratops ("three-horned face"); Triconodon ("three coned teeth"); trilobite ("three lobes")titano-, -titan: Pronunciation: /taɪtænoʊ/, /taɪtən/. Origin: Ancient Greek Τιτάν, Τιτᾶνος (Titán, Titânos). Meaning: Titan, of the Titan, respectively. Used for large animals.Examples: Titanosaurus ("Titan lizard"); Giraffatitan ("giraffe Titan"); Anatotitan ("duck Titan") Titanoboa ("Titanic boa")tyranno-, -tyrannus: Pronunciation: /taɪrænoʊ/, /taɪrænəs/. Origin: Ancient Greek τύραννος (túrannos). Meaning: tyrant. Used for animals similar to Tyrannosaurus.Examples: Tyrannosaurus ("tyrant lizard"); Nanotyrannus ("dwarf tyrant"); Tyrannotitan ("Titanic tyrant")veloci-: Origin: Latin velox. Meaning: speed.Example: Velociraptor ("quick thief")-venator: Pronunciation: /vɛnətər/. Origin: Latin venator. Meaning: hunter.Examples: Afrovenator ("African hunter"); Juravenator ("Jura hunter"); Scorpiovenator ("scorpion hunter") Neovenator ("new hunter"); Concavenator ("Cuenca hunter")xeno-: Pronunciation: /zinoʊ/. Origin: Ancient Greek ξένος (xénos). Meaning: strange, stranger. Used for organisms that exhibit unusual traits for their class.Examples: Xenosmilus ("strange knife") Xenotarsosaurus ("strange ankled lizard") Xenopsitta ("strange parrot") Xenocyon ("strange dog") Xenokeryx ("strange horn") Xenostega ("strange roof") Xenohyla ("strange hynadae") Xenozancla ("strange animal") Xenodermus ("strange mover")-zoon, -zoa: Pronunciation: /zoʊɑːn/, /zoʊə/. Origin: Ancient Greek ζῷον (zōion). Meaning: animal. Used for broad categories of animals, or in certain names of animals.Examples: metazoa ("encompassing animals"); parazoa ("near animals"); ecdysozoa ("moulting animals"); Yunnanozoon ("animal from Yunnan"); Yuyuanozoon ("animal from Yu Yuan")

List of dinosaur genera

This list of dinosaurs is a comprehensive listing of all genera that have ever been included in the superorder Dinosauria, excluding class Aves (birds, both living and those known only from fossils) and purely vernacular terms.

The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomen dubium), or were not formally published (nomen nudum), as well as junior synonyms of more established names, and genera that are no longer considered dinosaurs. Many listed names have been reclassified as everything from birds to crocodilians to petrified wood. The list contains 1559 names, of which approximately 1192 are considered either valid dinosaur genera or nomina dubia.

List of non-avian dinosaur species preserved with evidence of feathers

Several non-avian dinosaurs were feathered. Direct evidence of feathers exists for the following species, listed in the order currently accepted evidence was first published. In all examples, the evidence described consists of feather impressions, except those genera inferred to have had feathers based on skeletal or chemical evidence, such as the presence of quill knobs (the anchor points for wing feathers on the forelimb) or a pygostyle (the fused vertebrae at the tail tip which often supports large feathers).

Ostromia crassipes (1970)

Avimimus portentosus (inferred 1987: ulnar ridge)

Sinosauropteryx prima (1996)

Fulicopus lyellii, an ichnotaxon, possible squatting Dilophosaurus or similar. (1996)

Protarchaeopteryx robusta (1997)

GMV 2124 (1997)

Caudipteryx zoui (1998)

Rahonavis ostromi (inferred 1998: quill knobs; possibly avialan)

Shuvuuia deserti (1999)

Beipiaosaurus inexpectus (1999)

Sinornithosaurus millenii (1999)

Caudipteryx dongi (2000)

Caudipteryx sp. (2000)

Microraptor zhaoianus (2000)

Nomingia gobiensis (inferred 2000: pygostyle)

Psittacosaurus sp.? (2002)

Scansoriopteryx heilmanni (2002; possibly avialan)

Yixianosaurus longimanus (2003)

Dilong paradoxus (2004)

Pedopenna daohugouensis (2005; possibly avialan)

Jinfengopteryx elegans (2005)

Juravenator starki (2006)

Sinocalliopteryx gigas (2007)

Velociraptor mongoliensis (inferred 2007: quill knobs)

Epidexipteryx hui (2008; possibly avialan)

Similicaudipteryx yixianensis (inferred 2008: pygostyle; confirmed 2010)

Anchiornis huxleyi (2009; possibly avialan)

Tianyulong confuciusi? (2009)

Concavenator corcovatus? (inferred 2010: quill knobs?)

Xiaotingia zhengi (2011; possibly avialan)

Yutyrannus huali (2012)

Sciurumimus albersdoerferi (2012)

Ornithomimus edmontonicus (2012)

Ningyuansaurus wangi (2012)

Eosinopteryx brevipenna (2013; possibly avialan)

Jianchangosaurus yixianensis (2013)

Aurornis xui (2013; possibly avialan)

Changyuraptor yangi (2014)

Kulindadromeus zabaikalicus? (2014)

Citipati osmolskae (inferred 2014: pygostyle)

Conchoraptor gracilis (inferred 2014: pygostyle)

Deinocheirus mirificus? (inferred 2014: pygostyle)

Yi qi (2015)

Ornithomimus sp. (2015)

Zhenyuanlong suni (2015)

Dakotaraptor steini (inferred 2015: quill knobs)

Apatoraptor pennatus (inferred 2016: quill knobs)

Jianianhualong tengi (2017)

Serikornis sungei (2017)

Caihong juji (2018)Note that the filamentous structures in some ornithischian dinosaurs (Psittacosaurus, Tianyulong and Kulindadromeus) and the pycnofibres found in some pterosaurs may or may not be homologous with the feathers of theropods.

National Geographic Dinosaurs

National Geographic Dinosaurs is a nonfiction reference book on dinosaurs, written by Paul Barrett, with illustrations by Raúl Martín, and an introduction by Kevin Padian. It was published in 2001 by National Geographic.

Nemegt Formation

The Nemegt Formation (or Nemegtskaya Svita) is a geological formation in the Gobi Desert of Mongolia, dating to the Late Cretaceous. It overlies and sometimes interfingers with the Barun Goyot Formation. Interfingering has been noted at the stratotype (Red Walls) and Khermeen Tsav. It consists of river channel sediments and contains fossils of fish, turtles, crocodilians, and a diverse fauna of dinosaurs, including birds. The climate associated with it was wetter than when preceding formations were deposited; there seems to have existed at least some degree of forest cover. Fossilized trunks have been also found.

There has been no absolute dating of the Nemegt Formation. It is, however, almost certainly early Maastrichtian c 71-70 Ma. Gradzinski and others considered a Campanian age possible but more recent research indicates otherwise. A Campanian age no longer seems credible, because the Alagteegian (or lower Djadokhtan, at the locality "Chuluut Uul") has been radiometrically dated at about 73.5 Ma or even younger (a more recent K/Ar date is 71.6 +/- 1.6 Ma). The c 73.5 (or perhaps 72) Ma Alagteegian is separated from the Nemegt by the "classic" Djadokhtan (e.g. Bayan Dzag), later Djadohktan (represented by Ukhaa Tolgod) and Barungoyotian (Khulsan). All these intervening horizons almost certainly represent more than the 1.5 million years between the dated Alagteegian level and the onset of Maastrichtian time (72.1 million Ma according to current dating). Ergo the Nemegt is entirely Maastrichtian. See also Shuvalov, Sochava and Martinsson The Age of Dinosaurs in Russia and Mongolia. The presence of Saurolophus further supports an early Maastrichtian age as the same genus occurs in the early Maastrichtian Horseshoe Canyon formation.

Neural spine sail

A neural spine sail is a large, flattish protrusion from the back of an animal colinear with the spine. Many extinct species of amphibians and amniotes have extended neural spines growing from their back vertebrae. These are thought to have supported a sail. Paleontologists have proposed a number of ways in which the sail could have functioned in life.

Nqwebasaurus

Nqwebasaurus (IPA: [ᵑǃʷɛbaˈsɔɹəs]; anglicized as or ) is a basal coelurosaur and is the basal-most member of the coelurosaurian clade Ornithomimosauria from the Early Cretaceous of South Africa. The name Nqwebasaurus is derived from the Xhosa word "Nqweba" which is the local name for the Kirkwood district, and "thwazi" is ancient Xhosa for lightning. Currently it is the only known coelurosaur discovered in Africa and shows that basal coelurosaurian dinosaurs inhabited Gondwana 50 million years earlier than previously thought. The type specimen of Nqwebasaurus was discovered by William J. de Klerk who is affiliated with the Albany Museum in Grahamstown. It is the only fossil of its species found to date and was found in the Kirkwood Formation of the Uitenhage Group. Nqwebasaurus has the unofficial nickname "Kirky", due to being found in the Kirkwood.

Ornithomimosauria

The Ornithomimosauria, ornithomimosaurs ("bird-mimic lizards") or ostrich dinosaurs are theropod dinosaurs which bore a superficial resemblance to modern ostriches. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous Period of Laurasia (now Asia, Europe and North America), as well as Africa and possibly Australia. The group first appeared in the Early Cretaceous and persisted until the Late Cretaceous. Primitive members of the group include Nqwebasaurus, Pelecanimimus, Shenzhousaurus, Hexing and Deinocheirus, the arms of which reached 2.4 m (8 feet) in length. More advanced species, members of the family Ornithomimidae, include Gallimimus, Struthiomimus, and Ornithomimus. Some paleontologists, like Paul Sereno, consider the enigmatic alvarezsaurids to be close relatives of the ornithomimosaurs and place them together in the superfamily Ornithomimoidea (see classification below).

Tarbosaurus

Tarbosaurus ( TAR-bə-SAWR-əs; meaning "alarming lizard") is a genus of tyrannosaurid theropod dinosaur that flourished in Asia about 70 million years ago, at the end of the Late Cretaceous Period. Fossils have been recovered in Mongolia, with more fragmentary remains found further afield in parts of China.

Although many species have been named, modern paleontologists recognize only one, T. bataar, as valid. Some experts see this species as an Asian representative of the North American genus Tyrannosaurus; this would make the genus Tarbosaurus redundant. Tarbosaurus and Tyrannosaurus, if not synonymous, are considered to be at least closely related genera. Alioramus, also from Mongolia, has previously been thought by some authorities to be the closest relative of Tarbosaurus, though this has since been disproven with the discovery of Qianzhousaurus and the description of the Alioramini.

Like most known tyrannosaurids, Tarbosaurus was a large bipedal predator, weighing up to five tonnes and equipped with about sixty large teeth. It had a unique locking mechanism in its lower jaw and the smallest forelimbs relative to body size of all tyrannosaurids, renowned for their disproportionately tiny, two-fingered forelimbs.

Tarbosaurus lived in a humid floodplain criss-crossed by river channels. In this environment, it was an apex predator, probably preying on other large dinosaurs like the hadrosaur Saurolophus or the sauropod Nemegtosaurus. Tarbosaurus is represented by dozens of fossil specimens, including several complete skulls and skeletons. These remains have allowed scientific studies focusing on its phylogeny, skull mechanics, and brain structure.

Therizinosaurus

Therizinosaurus (; 'scythe lizard', from Ancient Greek θερίζω, meaning 'to reap', and σαῦρος, meaning 'lizard') is a genus of very large theropod dinosaurs. Therizinosaurus comprises the single species T. cheloniformis, which lived in the late Cretaceous Period (early Maastrichtian stage, around 70 million years ago), and was one of the last and largest representatives of its unique group, the Therizinosauria. Fossils of this species were first discovered in Mongolia and were originally thought to belong to a turtle-like reptile (hence the species name, T. cheloniformis – "turtle-formed"). It is known only from a few bones, including gigantic hand claws, from which it gets its name.

Timeline of ornithomimosaur research

This timeline of ornithomimosaur research is a chronological listing of events in the history of paleontology focused on the ornithomimosaurs, a group of bird-like theropods popularly known as the ostrich dinosaurs. Although fragmentary, probable, ornithomimosaur fossils had been described as far back as the 1860s, the first ornithomimosaur to be recognized as belonging to a new family distinct from other theropods was Ornithomimus velox, described by Othniel Charles Marsh in 1890. Thus the ornithomimid ornithomimosaurs were one of the first major Mesozoic theropod groups to be recognized in the fossil record. The description of a second ornithomimosaur genus did not happen until nearly 30 years later, when Henry Fairfield Osborn described Struthiomimus in 1917. Later in the 20th century, significant ornithomimosaur discoveries began occurring in Asia. The first was a bonebed of "Ornithomimus" (now Archaeornithomimus) asiaticus found at Iren Debasu. More Asian discoveries took place even later in the 20th century, including the disembodied arms of Deinocheirus mirificus and the new genus Gallimimus bullatus. The formal naming of the Ornithomimosauria itself was performed by Rinchen Barsbold in 1976.Early research into ornithomimosaur evolution was based on comparative anatomy. In 1972, Dale Russell argued that the Jurassic Elaphrosaurus of Africa was an ancestral relative of ornithomimids. The descriptions of Garudimimus and Harpymimus in the 1980s revealed the existence of primitive ornithomimosaurs outside of the Ornithomimidae proper. Subsequent research and discoveries during the 1990s refined science's knowledge of ornithomimosaur evolution. In 1994, Pelecanimimus polyodon was described from Europe, the first known ornithomimosaur from that continent and apparently a very evolutionarily primitive taxon. From the late 1990s into the early 21st century cladistic evidence mounted against Russell's hypothesis that ornithomimosaurs were descended from a close relative of Elaphrosaurus, and favored an ancestry close to Pelecanimimus. Paleontologists found that within the theropod family tree, ornithomimosaurs were primitive coelurosaurs closely related to, but outside of, the maniraptorans.The juxtaposition of apparent evolutionary affinities to carnivorous dinosaurs with the possession of toothless beaks has led to controversy among paleontologists trying to reconstruct the diet of ornithomimosaurs. Osborn hypothesized in 1917 that ornithomimosaurs may have eaten plants, social insects, or aquatic invertebrates. In the 1970s paleontologists Russell, Halszka Osmolska, and her colleagues considered ornithomimosaurs carnivores that may have fed on insects, small vertebrates, or eggs. In the early to mid 1980s, however Russell and Elizabeth Nicholls began advocating a reinterpretation of ornithomimosaurs as herbivores. With the 1999 report of gastroliths in the new genus Sinornithomimus, came further support for reinterpreting ornithomimosaurs as herbivores or filter feeders rather than carnivores. In 2001, Mark Norell reported a comb-like structure in the beak of Gallimimus that may have been used for filter feeding, bringing renewed credibility to one of Osborn's 1917 hypotheses. If this interpretation of the evidence is correct, Gallimimus would be the largest terrestrial filter feeder in history.

Basal ornithomimosaurs
Ornithomimoidea

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.