Gallimimus

Gallimimus (/ˌɡælɪˈmaɪməs/ 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.

Gallimimus
Temporal range: Late Cretaceous, 70 Ma
Gallimimus bullatus.001 - Natural History Museum of London
Reconstructed skeleton (based on the adult holotype and a juvenile specimen), Natural History Museum, London
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Clade: Ornithomimosauria
Family: Ornithomimidae
Genus: Gallimimus
Osmólska et al., 1972
Species:
G. bullatus
Binomial name
Gallimimus bullatus
Osmólska et al., 1972
Synonyms

Description

Gallimimus Size Comparison by PaleoGeek
Size compared to a human

Gallimimus is the largest known member of the family Ornithomimidae. The adult holotype (specimen IGM 100/11) was about 6 metres (20 ft) long and 1.9 metres (6.2 ft) tall at the hip; its skull was 330 millimetres (1.08 ft) long and the femur (thigh bone) was 660 millimetres (2.17 ft). It would have weighed about 440 kilograms (970 lb). In comparison, one juvenile specimen (ZPAL MgD-I/94) was about 2.15 metres (7.1 ft) long, 0.79 metres (2.6 ft) tall at the hip, and weighed about 26 kilograms (57 lb).[1] Based on fossils of the related Ornithomimus, it is known that ornithomimosaurs were feathered, and that the adults bore wing-like structures as evidenced by the presence of quill-knobs on the ulna bone of the lower arm, bumps that indicate where feathers would have attached.[2]

Skull

Gallimimus bullatus.002 - Natural History Museum of London (white background)
Reconstructed skull and neck, NHM

The head of Gallimimus was very small and light compared to the vertebral column. Due to the length of its snout, the skull was long compared to other ornithomimids, and the snout had a gently sloping upper profile; this was less distinct in juvenile specimens. The side profile of the snout differed from other ornithomimids in not narrowing towards its front half, and the lower front margin of the premaxilla at the front of the upper jaw rose upwards, instead of being horizontal. Seen from above, the snout was almost spatulate (spoon-shaped), broad and rounded at the tip (or U-shaped), whereas it was acute (or V-shaped) in North American ornithomimids. The orbits (eye sockets) were large and faced sideways, as in other ornithomimids. The temporal region at the side of the skull behind the eyes was deep, and the infratemporal fenestra (the lower opening behind the orbit) was nearly triangular and smaller than that of the related Struthiomimus. It had deep muscle scars at the back part of the skull roof, along the parietal bone. The parasphenoid (a bone at the underside of the skull's base) was thin-walled, hollow and formed a pear-shaped, bulbous structure. The structure had a shallow furrow which opened at the base of the skull. The internal nares (internal openings for the nasal passage) were large and placed far back on the palate, due to the presence of an extensive secondary palate, which was common to ornithomimids.[3][4][5][6]

The delicate lower jaw, consisting of thin bones, was slender and shallow at the front, deepening towards the rear. The front of the mandible was shovel-like, resulting in a gap between the tips of the jaws when shut. The shovel-like shape was similar to that of the common seagull, and the lower beak may have had a shape similar to that of this bird. The retroarticular process at the back of the jaw (where jaw muscles attached) was well developed and consisted mainly of the angular bone. The surangular was the largest bone of the lower jaw, which is usual in theropods. The mandibular fenestra, a sidewards-facing opening in the lower jaw, was elongated and comparatively small. The lower jaw did not have a coronoid process or a supradentary bone, the lack of which is a common feature of beaked theropods (ornithomimosaurs, oviraptorosaurs, therizinosaurs and birds), but unusual among theropods in general. The shape and proportions of the skull changed significantly during growth. The rear of the skull and the orbits decreased in size, whereas the snout became relatively longer, similar changes occur in modern crocodiles. The skull was also proportionally larger in the younger specimens.[3][7] The jaws of Gallimimus were edentulous (toothless), and the front part would have been covered in a keratinous rhamphotheca (horny beak) in life. The beak may have covered a smaller area than in North American relatives, based on the lack of nourishing foramina on the maxilla. The inner side of the beak had small, tightly packed and evenly spaced columnar structures (their exact nature is debated), which were longest at the front and shortening towards the back.[5][7][8]

Postcranial skeleton

Pneumatic structures in Senzhousaurus and Gallimimus
Pneumatic structures in the caudal vertebrae of Shenzhousaurus (A), and the cervical (B, C, D), dorsal (E), sacral (F, G) and caudal (H) vertebrae of Gallimimus

Gallimimus had 64–66 vertebrae in its spine, fewer than other ornithomimids. The centra (or bodies) of the vertebrae were platycoelous, with a flat front surface and a concave hind surface, except for the first six caudal (tail) vertebra–where the hind surface was also flat–and those at the end of the tail–which were amphiplatyan with both surfaces flat. Many of the centra had foramina (openings which have also been called "pleurocoels"), and were therefore probably pneumatic (with their hollow chambers invaded by air sacs). The neck consisted of 10 cervical vertebrae, which were all long and wide, except for the atlas bone (the first vertebra that connects with the back of the skull). The atlas differed from that of other ornithomimids in that the surface of its intercentrum was slanted downwards towards the back, instead of being concave and facing upwards. The neck appears to have been proportionally longer in relation to the trunk than in other ornithomimids. The neck was divided into two distinct sections: the cervical vertebrae at the front had centra which were nearly triangular in side view and tapered towards the back, as well as low neural arches and short, broad zygapophyses (the processes that articulated between the vertebrae); the cervical vertebrae at the back had spool-like centra which became gradually higher, and long, thin zygapophyses. The pneumatic foramina here were small and oval, and the neural spines projecting outwards from the centra formed long, low and sharp ridges, except for in the hindmost cervical vertebrae.[3][9]

The back of Gallimimus had 13 dorsal vertebrae, with spool-like centra that were short, but tended to become deeper and longer towards the back. Their transverse processes (processes articulating with the ribs) slightly increased in length towards the back. The two first dorsal centra had deep pneumatic foramina, while the rest only had shallow fossae (depressions), and the neural spines were prominent being somewhat triangular or rectangular in shape. The sacrum (fused vertebrae between the pelvic bones) consisted of five sacral vertebrae which were about equal in length. The centra here were spool-like, flattened sideways and had fossae which appear to have continued as deep foramina in some specimens. The neural spines here were rectangular, broad, and higher than those in the dorsal vertebrae. They were higher or equal in height to the upper margin of the iliac blade and were separate, whereas in other ornithomimids they were fused together. The tail had 36–39 caudal vertebrae with the centra of those at the front being spool-shaped, while those at the back were nearly triangular, and elongated across. The neural spines here were high and flat, but diminished backwards, where they became ridge-like. The only sign of pneumaticity in the tail were deep fossae between the neural spies and the transverse process of the two first caudal vertebrae. All the vertebrae in front of the sacrum bore ribs except for the atlas and the last dorsal vertebra. The ribs in the neck were fused to the vertebrae only in adults.[3][9]

Gallimimus Steveoc86
Restoration showing an adult with feathers, based on those known from the related Ornithomimus

The scapula (shoulder blade) was short and curved, thin at the front end, and thick at the back. It was connected relatively weakly with the coracoid, which was large and deep from top to bottom. Overall, the forelimbs did not differ much from those of other ornithomimids, all of which were comparatively weak. The humerus (upper arm bone), which had a near circular cross-section, was long and twisted. The deltopectoral crest on the upper front part of the humerus was comparatively small, and therefore provided little surface for attachment of upper arm muscles. The ulna was slender, long and weakly curved, with a nearly triangular shaft. The olecranon (the projection from the elbow) was prominent in adults, but not well developed in juveniles. The radius (the other bone in the lower arm) was long and slender with a more expanded upper end compared to the lower. The manus (hand) was proportionally short compared to those of other ornithomimosaurs, having the smallest manus to humerus length ratio of any member of the group, but was otherwise similar in structure. It had three fingers, which were similarly developed; the first (the "thumb") was the strongest, the third was the weakest and the second was the longest. The unguals (claw bones) were strong, somewhat curved (that of the first finger was most curved) and compressed sideways with a deep groove on each side. The unguals were similarly developed, though the third was slightly smaller. The forelimbs appear to have become proportionally longer during growth.[3][10][4]

The pubis (pubic bone) was long and slender, ending in a pubic boot which expanded to the front and back, a general feature of ornithomimosaurs. The hind limbs differed little from those of other ornithomimids, and were proportionally longer than in other theropods. The femur was nearly straight, long and slender, with a sideways flattened shaft. The tibia was straight, long, with two well developed condyles (rounded end of a bone) on the upper end and a flattened lower end. The fibula of the lower leg was flat, thin and broad at the upper end narrowing towards the lower end. The lower half of the third metatarsal was broad when viewed end on, partly covering the adjoining two metatarsals to each side, but narrowed abruptly at mid-length, wedging between those bones and disappearing (an arctometatarsalian foot structure). The third toe was proportionally shorter in relation to the limb than in other ornithomimids. As in other ornithomimids, the foot had no hallux (or dewclaw, the first toe of most other theropods). The unguals of the toes were flat on their lower sides; the outer two declined slightly outwards from their digits. The proportional length of the bones in the hind limbs changed very little with growth.[3][4]

History of discovery

Nemegt locality
The Nemegt locality (✪) in the Nemegt Basin of southern Mongolia, where some Gallimimus specimens have been found

Between 1963 and 1965, the Polish Academy of Sciences and the Mongolian Academy of Sciences organised the Polish-Mongolian palaeontological expeditions to the Gobi Desert of Mongolia. Among the dinosaur remains discovered in sand beds of the Nemegt Basin were numerous ornithomimids at different growth stages from the Nemegt, Tsaagan Khushuu, Altan Ula IV and Naran Bulak localities. Three partially complete skeletons, two with skulls, as well as many fragmentary remains, were collected. The largest skeleton (later to become the holotype of Gallimimus bullatus) was discovered by palaeontologist Zofia Kielan-Jaworowska in Tsaagan Khushuu in 1964; it was preserved lying on its back, and the skull was found under its pelvis. One small specimen was also found in Tsaagan Khushuu the same year, and another small specimen was found in the Nemegt locality. A small skeleton without forelimbs was discovered in 1967 by the Mongolian palaeontological expedition in Bugeen Tsav outside the Nemegt Basin. The fossils were housed at the Mongolian, Polish and USSR Academy of Sciences.[3][11][12] The Polish-Mongolian expeditions were notable for being led by women, some of which were among the first women to name new dinosaurs. The fossils discovered in these expeditions shed new light on the interchange of fauna between Asia and North America during the Cretaceous period.[13][14][15] Some of the skeletons were exhibited in Warsaw in 1968, mounted in tall, semi-erect postures, which was accepted at the time, though more horizontal postures are favoured today.[15]

Scan00gall14
Adult holotype skeleton IGM 100/11, during a temporary exhibition in Experimentarium, Hellerup

In 1972, palaeontologists Halszka Osmólska, Ewa Roniewicz and Rinchen Barsbold named the new genus and species Gallimimus bullatus, using the largest collected skeleton, specimen IGM 100/11 (from Tsaagan Khushuu, formerly referred to as G.I.No.DPS 100/11 and MPD 100/11), as the holotype. The generic name is derived from the Latin gallus, "chicken", and the Greek mimos, "mimic", in reference to the front part of the neck vertebrae which resembled those of the Galliformes. The specific name is derived from the Latin bulla, a gold capsule worn by Roman youth around the neck, in reference to the bulbous capsule on the parasphenoid at the base of the dinosaur's skull. Such a feature had not been described from other reptiles at the time, and was considered unusual. The holotype consists of an almost complete skeleton with a distorted snout, incomplete lower jaw, vertebral series, pelvis, as well as some missing hand and foot bones.[3][16] The other partially complete skeletons were juveniles; ZPAL MgD-I/1 (from Tsaagan Khushuu) has a crushed skull with a missing tip, damaged vertebrae, fragmented ribs, pectoral girdle and forelimbs, and an incomplete left hind limb, ZPAL MgD-I/94 (from the Nemegt locality) lacks the skull, atlas, tip of the tail, pectoral girdle and forelimbs, while the smallest specimen, IGM 100/10 (from Bugeen Tsav), lacks a pectoral girdle, forelimbs and several vertebrae and ribs. Osmólska and colleagues listed 25 known specimens in all, 9 of which were only represented by single bones.[3][10]

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. Ornithomimids were previously known mainly from North America, Archaeornithomimus being the only prior known member from Asia (though without a skull). Since the first discoveries, more specimens have been found by further Mongolian-led international expeditions.[3][10][14][15] Three of the Gallimimus skeletons (including the holotype) later became part of a travelling exhibit of Mongolian dinosaur fossils, which toured various countries.[17][18] Fossil poaching has become a serious problem in Mongolia in the 21st century, and several Gallimimus specimens have been looted. In 2017, Hang-Jae Lee and colleagues reported a fossil trackway discovered in 2009 associated with a clenched Gallimimus foot (specimen MPC-D100F/17). The rest of the skeleton appeared to have been removed previously by poachers, along with several other Gallimimus specimens (as indicated by empty excavation pits, garbage, and scattered broken bones in the quarry). It is unusual to find tracks closely associated with body fossils; some of the tracks are consistent with ornithoimimid feet, while others belong to different dinosaurs.[19][20]

Gallimimus fossils
Three skeletons, including the holotype at right, during a temporary exhibition in CosmoCaixa Barcelona

In 1988, the palaeontologist Gregory S. Paul concluded that the skulls of ornithomimids were more similar to each other than previously thought and moved most species into the same genus, Ornithomimus, resulting in the new combination O. bullatus.[1] In 2010, he instead used the combination Struthiomimus bullatus.[21] The species involved have generally been kept in separate genera by other writers.[4] An ornithomimid vertebra from Japan informally named "Sanchusaurus" was reported in a 1988 magazine, but was assigned to Gallimimus sp. (of uncertain species) by the palaeontologist Dong Zhiming and colleagues in 1990.[16] Barsbold informally referred to a nearly complete skeleton (IGM 100/14) as "Gallimimus mongoliensis", but since it differs from Gallimimus in some details, Yoshitsugu Kobayashi and Barsbold proposed in 2006 that it probably belongs to a different genus. In 2000, the palaeontologist Philip J. Currie proposed that Anserimimus, which is only known from one skeleton from Mongolia, was a junior synonym of Gallimimus, but this was dismissed by Kobayashi and Barsbold, who pointed out several differences between the two. Barsbold noted some morphological variation among newer Gallimimus specimens, though this has never been published.[10]

Classification

Osmólska and colleagues assigned Gallimimus to the family Ornithomimidae in 1972, with the North American Struthiomimus as the closest relative, while lamenting the fact that comparison between taxa was difficult because other ornithomimids known at the time were either poorly preserved or inadequately described.[3] In 1975, Kielan-Jaworowska stated that though many dinosaurs from Asia were placed in the same families as North American relatives, this category of classification tended to be more inclusive than was used for modern birds. She highlighted that while Gallimimus had a rounded beak (similar to a goose or duck), North American ornithomimids had pointed beaks, a difference that would otherwise lead taxonomists to place modern birds in different families.[14] In 1976, Barsbold placed Ornithomimidae in the new group Ornithomimosauria (the "ostrich dinosaurs"). In 2003, Kobayashi and Jun-Chang Lü found that Anserimimus was the sister taxon to Gallimimus, both forming a derived (or "advanced") clade with North American genera, which was confirmed by Kobayashi and Barsbold in 2006.[10][5]

The following cladogram shows the placement of Gallimimus among Ornithomimidae according to Li Xu and colleagues, 2011:[22]

MEPAN Gallimimus bullatus skeleton copy
Cast of the holotype skeleton in a semi-erect posture, Museum of Evolution of Polish Academy of Sciences, Warsaw
Ornithomimidae

Archaeornithomimus

unnamed

Sinornithomimus

unnamed

Anserimimus

Gallimimus

unnamed

Qiupalong

unnamed

Struthiomimus

Ornithomimus

Ornithomimosaurs belonged to the clade Maniraptoriformes of coelurosaurian theropods, which also includes modern birds. Early ornithomimosaurs had teeth, which were lost in more derived members of the group.[23] In 2004, Makovicky, Kobayashi, and Currie suggested that most of the early evolutionary history of ornithomimosaurs took place in Asia, where most genera have been discovered, including the most basal (or "primitive") taxa, although they acknowledged that the presence of the basal Pelecanimimus in Europe presents a complication in classification. The group must have dispersed once or twice from Asia to North America across Beringia to account for the Late Cretaceous genera found there. As seen in some other dinosaur groups, ornithomimosaurs were largely restricted to Asia and North America after Europe was separated from Asia by the Turgai Strait.[4]

In 1994, the palaeontologist Thomas R. Holtz grouped ornithomimosaurs and troodontids in a clade, based on shared features such as the presence of a bulbous capsule on the parasphenoid. He named the clade Bullatosauria, based on the specific name of Gallimimus bullatus, which was also in reference to the capsule.[24] In 1998, Holtz instead found that troodontids were basal maniraptorans, meaning that all members of that clade would fall within Bullatosauria, which would therefore become a junior synonym of Maniraptoriformes, and the clade has since fallen out of use.[25][26]

Palaeobiology

Denis Bourez - Natural History Museum, London (8900329973)
Reconstructed skull and neck in front view, NHM

The cervical vertebrae of Gallimimus indicate that it held its neck obliquely, declining upwards at an angle of 35 degrees. Osmólska and colleagues found that the hands of Gallimimus were not prehensile (or capable of grasping), and that the thumb was not opposable. They also suggested that the arms were weak compared to, for example, those of the ornithomimosaur Deinocheirus. They agreed with the interpretations of ornithomimid biology by palaeontologist Dale Russell from earlier in 1972, including that they would have been very fleet (or cursorial) animals, although less agile than large, modern ground birds, and would have used their speed to escape predators. Russell also suggested that they had a good sense of vision and intelligence comparable to that of modern ratite birds. Since their predators may have had colour vision, he suggested it would have influenced their colouration, perhaps resulting in camouflage.[3][27] In 1982, palaeontologist Richard A. Thulborn estimated that Gallimimus could have run at speeds of 42-56 km/h (29-34 mph). He found that ornithimimids would not have been as fast as ostriches, which can reach 70-80 km/h (43-49 mph), in part due to their arms and tails increasing their weight.[28]

Gallimimus bullatus leg bones
Hindlimb bones of ZPAL MgD-I/8, MEPAS

In 1988, Paul suggested that the eyeballs of ornithomimids were flattened and had minimal mobility within the sockets, necessitating movement of the head to view objects. Since their eyes faced more sideways than in some other bird-like theropods, their binocular vision would have been more limited, which is an adaptation in some animals that improves their ability to see predators behind them. Paul considered the relatively short tails, which reduced weight, and missing halluxes of ornithomimids to be adaptations for speed. He suggested that they could have defended themselves by pecking and kicking, but would have mainly relied on their speed for escape.[1] In 2015, Akinobu Watanabe and colleagues found that together with Deinocheirus and Archaeornithomimus, Gallimimus 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, that it was related to high metabolism, balance during locomotion, or used for thermoregulation.[9]

In 2017, Lee and colleagues suggested various possible taphonomic circumstances (changes during decay and fossilisation) to explain how the Gallimimus foot discovered in 2009 was associated with a trackway. The trackway is preserved in sandstone while the foot is preserved in mudstone, extending 20 centimetres (7.9 in) below the layer with the tracks. It is possible the fossil represents an animal that died in its tracks, but the depth of the foot in the mud may be too shallow for it to have become mired. It may also have been killed by a flood, after which it was buried in a pond. However, the layers of mud and sand do not indicate flooding but probably a dry environment, and the disrupted sediments around the fossil indicate the animal was alive when it came to the area. The authors thus suggested that the tracks had been made over an extended amount of time and period of drying, and that probably none of them were produced by the individual that owned the foot. The animal may have walked across the floor of a pond, breaking through the sediment layer with the tracks while it was soaked from rain or contained water. The animal may have died in this position from thirst, hunger, or another reason, and mud then deposited on the sand, thereby covering and preserving the tracks and the carcass. The foot may have become clenched and disarticulated as it decomposed, which made the tendons flex, and was later stepped on by heavy dinosaurs. The area may have been a single bone bed (based on the possible number of poached specimens) representing a Gallimimus mass mortality, perhaps due to a drought or famine. The fact that the animals seem to have died at the same time (the empty excavation pits were stratigraphically identical) may indicate that Gallimimus was gregarious (lived in groups), which has also been suggested for other ornithomimids.[20]

Development

Gallimimusbcn1
Smallest known Gallimimus, the juvenile specimen IGM 100/10, exhibited in CosmoCaixa

A 1987 study by the biologists Roman Pawlicki and P. Bolechała showed age-related differences in the content of calcium and phosphorus (important components in the formation of bone) of Gallimimus specimens. They found that the ratio was highest in young to middle aged animals, decreasing with age.[29] In 1991, they reported that the bones of old individuals contained the highest amounts of lead and iron, while those in younger animals were lower.[30] A study of the bone histology of various dinosaurs in 2000, by biologists John M. Rensberger and Mahito Watabe, revealed that the canaliculi (channels which connect bone cells) and collagen fibre bundles of Gallimimus and other ornithomimids were more akin to those in birds than mammals, unlike those of ornithischian dinosaurs, which were more similar to mammals. These differences may have been related to the process and rate at which bone formed.[31] In 2012, palaeontologist Darla K. Zelenitsky and colleagues concluded that, since adult ornithomimosaurs had wing-like structures on their arms whereas juveniles did not (as evidenced by specimens of Ornithomimus), these structures were originally secondary sexual characteristics, which could have been used for reproductive behaviour such as courtship, display, and brooding.[2]

Feeding and diet

Gallimimus bullatus skull
Skull cast of the juvenile specimen ZPAL MgD-I/1, National Museum of Natural History, Paris

Osmólska and colleagues pointed out that the front part of the neck of Gallimimus would have been very mobile (the hind part was more rigid), the neural arches in the vertebrae of that region being similar to chicken and other Galliformes, indicating similar feeding habits. They found the beak of Gallimimus similar to that of a duck or goose, and that it would have fed on small, living prey which it swallowed whole. The mobility of the neck would have been useful in locating prey on the ground, since the eyes were positioned on the sides of the skull. They assumed that all ornithomimids had similar feeding habits, and pointed out that Russel had compared the beaks of ornithomimids with those of insectivorous birds. Osmólska and colleagues suggested that Gallimimus was capable of cranial kinesis (due to the seemingly loose connection between some of the bones at the back of the skull), a feature which allows individual bones of the skull to move in relation to each other. They also proposed that it did not use its short handed forelimbs for bringing food to the mouth, but for raking or digging in the ground to access food.[3] The hands of Gallimimus may have been weaker than for example those of Struthiomimus, which may instead have used its hands for hooking and gripping, according to a 1985 article by palaeontologists Elizabeth L. Nicholls and Anthony P. Russell.[32]

In 1988 Paul disagreed that ornithomimids were omnivores that ate small animals and eggs as well as plants, as had previously been suggested. He pointed out that ostriches and emus are mainly grazers and browsers, and that the skulls of ornithomimids were most similar to those of the extinct moas, which were strong enough to bite off twigs, as evidenced by their gut content. He further suggested that ornithomimids were well adapted for browsing on tough plants and would have used their hands to bring branches within reach of their jaws.[1] Palaeontologist Jørn Hurum suggested in 2001 that due to its similar jaw structure, Gallimimus may have had an opportunistic, omnivorous diet like seagulls. He also observed that the tight intramandibular joint would prevent any movement between the front and rear portions of the lower jaw.[7]

Northern shovler quack (14291478785)
The beak of Gallimimus contained structures which have been compared to the lamellae of, for example, the Northern shoveller, or the ridges in the beaks of turtles and hadrosaurids

In 2001, palaeontologists Mark A. Norell, Makovicky, and Currie reported a Gallimimus skull (IGM 100/1133) and an Ornithomimus skull that preserved soft tissue structures on the beak. The inner side of the Gallimimus beak had columnar structures that the authors found similar to the lamellae in the beaks of anseriform birds, which use these for manipulating food, straining sediments, filter-feeding by segregating food items from other material, and for cutting plants while grazing. They found the Northern shoveller, which feeds on plants, molluscs, ostracods, and foraminiferans, to be the modern anseriform with structures most similar in anatomy to those of Gallimimus. The authors noted that ornithomimids probably did not use their beaks to prey on large animals and were abundant in mesic environments, while rarer in more arid environments, suggesting that they may have depended on aquatic food sources.[8] If this interpretation is correct, Gallimimus would have been one of the largest known terrestrial filter feeders.[4]

In 2005, palaeontologist Paul Barrett pointed out that the lamella-like structures of Gallimimus did not appear to have been flexible bristles like those of filter-feeding birds (as there is no indication of these structures overlapping or being collapsed), but were instead more akin to the thin, regularly spaced vertical ridges in the beaks of turtles and hadrosaurid dinosaurs. In these animals, such ridges are thought to be associated with herbivorous diets, used to crop tough vegetation. Barrett suggested that the ridges in the beak of Gallimimus represented a natural cast of the internal surface of the beak, indicating that the animal was a herbivore that fed on material high in fibre. The discovery of many gastroliths (gizzard stones) in some ornithomimids indicate the presence of a gastric mill, and therefore point towards a herbivorous diet, as these are used to grind food of animals that lack the necessary chewing apparatus. Barrett also calculated that a 440 kilograms (970 lb) Gallimimus would have needed between 0.07 and 3.34 kilograms (0.15 and 7.36 lb) of food per day, depending on whether it had an endothermic or an ectothermic ("warm" or "cold"-blooded) metabolism, an intake which he found to be unfeasible if it was a filter feeder. He also found that ornithomimids were abundant not only in formations that represented mesic environments, but also in arid environments where there would be insufficient water to sustain a diet based on filter feeding.[6] In 2007, palaeontologist Espen M. Knutsen wrote that the beak shape of ornithomimids, when compared to those of modern birds, was consistent with omnivory or high-fibre herbivory.[33]

Palaeoecology

Gallimimus in Ulaanbaatar
Juvenile skeleton, Mongolian Natural History Museum, Ulaanbaatar

Gallimimus is known 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.[34][35][36] The sediments of the Gallimimus type locality Tsaagan Khushuu consist of silts, siltstones, mudstones, sands, as well as less frequent thin beds of sandstones.[12] The rock facies of the Nemegt Formation suggest the presence of river channels, mudflats, shallow lakes and floodplains in an environment similar to the Okavango Delta of present-day Botswana.[37] Large river channels and soil deposits are evidence of a significantly more humid climate than those found in the older Barun Goyot and Djadochta formations, although caliche deposits indicate that periodic droughts occurred.[38] Fossil bones from the Nemegt Basin, including of Gallimimus, are more radioactive than fossils from surrounding areas, possibly because uranium accumulated in the bones, transported there by percolating ground water.[15][39]

The Nemegt rivers, where Gallimimus lived, were home to a wide array of organisms. Occasional mollusc fossils, as well as a variety of other aquatic animals like fish, turtles,[34] and crocodylomorphs, including Shamosuchus, have been discovered in this region.[40] Mammal fossils are rare in the Nemegt Formation, but many birds, including the enantiornithine Gurilynia, the hesperornithiform Judinornis, as well as Teviornis, a possible anseriform, have been found. Herbivorous dinosaurs discovered in 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.[34][41] Predatory theropods that lived alongside Gallimimus include tyrannosauroids such as Tarbosaurus, Alioramus and Bagaraatan, and troodontids such as Borogovia, Tochisaurus and Zanabazar. Herbivorous or omnivorous theropods include therizinosaurs, such as Therizinosaurus, as well as oviraptorosaurians, such as Elmisaurus, Nemegtomaia, and Rinchenia.[42] Other ornithomimosaurs, including Anserimimus and Deinocheirus, are also found, but Gallimimus is the most common member of the group in the Nemegt.[10]

Cultural significance

MEPAN Gallimimus bullatus model
Gallimimus was formerly depicted without feathers, like this model in MEPAS

Gallimimus was featured in the 1993 movie Jurassic Park by director Steven Spielberg; a similar scene in the original 1990 novel instead featured hadrosaurs. Spielberg had wanted a stampede sequence with animal herds in the movie, but did not know how to achieve it, and it was initially going to be visualised through stop-motion animation. At the time, there was little faith in creating animals through computer animation, but the visual effects company Industrial Light and Magic was given a go-ahead by the movie's producers to explore possibilities. ILM created a Gallimimus skeleton in the computer and animated a test showing a herd of running skeletons, and later a Tyrannosaurus chasing a fully rendered Gallimimus herd. The production team became very enthusiastic as nothing similar had previously been achieved, and Spielberg was convinced to write the scene into the script, and to also use computer graphics for other dinosaur shots in the movie instead of stop motion.[43][44] The Gallimimus were animated by tracing frames from footage of ostriches, and footage of herding gazelles was also referenced.[45] Kielan-Jaworowska, who discovered the holotype specimen, called it a "beautiful scene".[15] The movie's dinosaurs were one of the most widely publicised applications of computer-generated imagery in film, and were considered more lifelike than what had been previously accomplished with special effects.[46]

Emphasising the bird-like flocking behaviour of the Gallimimus herd was a point in Jurassic Park's story, as they were supposed to represent the precursors to birds. The herd was shown moving as a whole, rather than individual animals running around, and the smaller Gallimimus were shown in the middle of the group, as though they were protected.[43] During the scene, the protagonist palaeontologist Alan Grant says that the herd moves with "uniform direction changes, just like a flock of birds evading a predator" and "bet you'll never look at birds the same way again" as he watches the movements of the fast, graceful Gallimimus. This contrasted with how dinosaurs were traditionally depicted in mass media as lumbering, tail-dragging animals, and the movie helped change the common perception of dinosaurs. This and other scenes reflected then-recent theories of bird evolution encouraged by the movie's scientific advisor, palaeontologist John R. Horner, ideas which were still contentious at the time.[47][48][49] Despite such theories, Gallimimus and other dinosaurs of the movie were depicted without feathers, in part because it was unknown at the time how widespread these were among the group.[47][50]

It has been claimed that the Lark Quarry tracks (one of the world's largest concentrations of dinosaur tracks) in Queensland, Australia, served as inspiration and "scientific underpinning" for the Gallimimus stampede scene in Jurassic Park; these tracks were initially interpreted as representing a dinosaur stampede caused by the arrival of a theropod predator. The idea that the tracks represent a stampede has since been contested (the "theropod" may instead have been a herbivore similar to Muttaburrasaurus), and a consultant to Jurassic Park has denied the tracks served as inspiration for the movie.[51][52][53]

See also

References

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1972 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 1972.

Aepyornithomimus

Aepyornithomimus (meaning "Aepyornis mimic") is a genus of ornithomimid theropod dinosaur from the Late Cretaceous Djadokhta Formation in Mongolia. It lived in the Campanian, around 80 million years ago, when the area is thought to have been a desert. The type and only species is A. tugrikinensis.

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.

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.

Deinocheirus

Deinocheirus ( 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.

Halszka Osmólska

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

Isla Nublar

Isla Nublar (English: Cloud Island; Site A) is a fictional Central American island in the Jurassic Park franchise, first depicted in Michael Crichton's eponymous 1990 novel. It is the primary setting of the 1993 film Jurassic Park, Jurassic World (2015) and Jurassic World: Fallen Kingdom (2018). Both the novel and film versions of the Jurassic Park theme park are located on Isla Nublar off the west coast of Costa Rica, which has leased the island to John Hammond, the CEO of fictional bio-engineering firm InGen.

The Las Cinco Muertes Archipelago (English: The Five Deaths) is a chain of five islands 200 miles southwest of Costa Rica. They are named Isla Matanceros, Isla Muerta, Isla Pena, Isla Sorna and Isla Tacaño. The name comes from a Native American myth about a brave warrior facing a different execution on each of the five islands: burning, drowning, crushing, hanging and beheading. InGen did not own these islands. They only had a 99-year lease of Isla Nublar from the Costa Rican Government, and owned Isla Sorna (English: Sarcasm Island; Site B); the only island populated with dinosaurs aside from Isla Nublar.

Jurassic Park (film)

Jurassic Park is a 1993 American science fiction adventure film directed by Steven Spielberg and produced by Kathleen Kennedy and Gerald R. Molen. The first installment in the Jurassic Park franchise, it is based on the 1990 novel of the same name by Michael Crichton and a screenplay written by Crichton and David Koepp. The film is set on the fictional island of Isla Nublar, located off Central America's Pacific Coast near Costa Rica. There billionaire philanthropist John Hammond and a small team of genetic scientists have created a wildlife park of de-extinct dinosaurs. When industrial sabotage leads to a catastrophic shutdown of the park's power facilities and security precautions, a small group of visitors, and Hammond's grandchildren, struggle to survive and escape the perilous island.

Before Crichton's novel was published, four studios put in bids for its film rights. With the backing of Universal Studios, Spielberg acquired the rights for $1.5 million before its publication in 1990; Crichton was hired for an additional $500,000 to adapt the novel for the screen. Koepp wrote the final draft, which left out much of the novel's exposition and violence and made numerous changes to the characters. Filming took place in California and Hawaii between August and November 1992, and post-production rolled until May 1993, supervised by Spielberg in Poland as he filmed Schindler's List.

The dinosaurs were created with groundbreaking computer-generated imagery by Industrial Light & Magic (ILM) and with life-sized animatronic dinosaurs built by Stan Winston's team. To showcase the film's sound design, which included a mixture of various animal noises for the dinosaur roars, Spielberg invested in the creation of DTS, a company specializing in digital surround sound formats. Following an extensive $65 million marketing campaign, which included licensing deals with 100 companies, Jurassic Park premiered on June 9, 1993, at the Uptown Theater in Washington, D.C., and was released on June 11 in the United States. It went on to gross over $914 million worldwide in its original theatrical run becoming the highest-grossing film of 1993 and the highest-grossing film ever at the time, a record held until the release of Titanic in 1997. It was well received by critics, who praised its special effects, John Williams' musical score, and Spielberg's direction. Following its 3D re-release in 2013 to celebrate its 20th anniversary, Jurassic Park became the seventeenth film in history to surpass $1 billion in ticket sales.

The film won more than twenty awards, including three Academy Awards for its technical achievements in visual effects and sound design. Jurassic Park is considered a landmark in the development of computer-generated imagery and animatronic visual effects and was followed by four commercially successful sequels, The Lost World: Jurassic Park (1997), Jurassic Park III (2001), Jurassic World (2015) and Jurassic World: Fallen Kingdom (2018), with a fifth and final sequel, currently titled Jurassic World 3, scheduled for a 2021 release.

In 2018, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".

List of cloned animals in the Jurassic Park series

Jurassic Park is an American science fiction adventure media franchise based on the 1990 best-selling novel of the same name by Michael Crichton, and its sequel, The Lost World (1995). Focused on the catastrophic events following the cloning of dinosaurs through the extraction of DNA from mosquitoes fossilized in amber, the film series also explores the ethics of cloning and genetic engineering, and the morals behind bringing back extinct animals. The first Jurassic Park film was directed by Steven Spielberg and released in 1993. It was followed by two films, The Lost World: Jurassic Park (1997) and Jurassic Park III (2001), completing the first trilogy. A fourth installment, Jurassic World, was released in 2015, marking the beginning of a new trilogy. The new trilogy starts 22 years after the events of the first, but still relies on the narrative of the original films and novels. Its sequel, Jurassic World: Fallen Kingdom, was released in 2018, and a sixth and final film of the second trilogy is scheduled for release in 2021. The film series has garnered critical acclaim for its innovations in CGI technology and animatronics.

47 species of cloned animals have been portrayed in the novels and films: 39 species of dinosaurs, three species of pterosaurs, three genetically-engineered animals, one species of prehistoric marine reptile, and at least one cloned Homo sapiens. Theropod dinosaurs like Tyrannosaurus rex and Velociraptor have had major roles throughout the series. Other species, including Triceratops, Brachiosaurus, and Spinosaurus have also played significant roles.

List of creatures by Impossible Pictures

The following is a complete list of prehistoric creatures from the universe of the Walking with... series documentary, science fiction and fantasy television programmes, companion books and also any spin-off merchandise. Most of the shows produced by Impossible Pictures with BBC Worldwide and Discovery Channel in association with ProSieben and France 3 and created by Tim Haines and Jasper James. They used visual effects teams such as Framestore, The Mill and Jellyfish Pictures to bring back extinct creatures to life.

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.

Nemegtosaurus

Nemegtosaurus (meaning 'Reptile from the Nemegt') was a sauropod dinosaur from Late Cretaceous Period of what is now Mongolia. Nemegtosaurus was named after the Nemegt Basin in the Gobi Desert, where the remains — a single skull — were found. The skull resembles diplodocoids in being long and low, with pencil-shaped teeth. However, recent work has shown that Nemegtosaurus is in fact a titanosaur, closely related to animals such as Saltasaurus, Alamosaurus and Rapetosaurus.

Ornithomimidae

Ornithomimidae (meaning "bird-mimics") is a group of 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 and North America). The group first appeared in the Early Cretaceous.

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).

Ornithomimus

Ornithomimus (; "bird mimic") is a genus of ornithomimid dinosaurs from the Late Cretaceous Period of what is now North America. Ornithomimus was a swift bipedal theropod which fossil evidence indicates was covered in feathers, equipped with a small toothless beak that may indicate an omnivorous diet. It is usually classified into two species: the type species, Ornithomimus velox, and a referred species, Ornithomimus edmontonicus. O. velox was named in 1890 by Othniel Charles Marsh on the basis of a foot and partial hand from the late Maastrichtian-age Denver Formation of Colorado, United States. Another seventeen species have been named since, though most of them have subsequently been assigned to new genera or shown to be not directly related to Ornithomimus velox. The best material of species still considered part of the genus has been found in Alberta, Canada, representing the species O. edmontonicus, known from several skeletons from the early Maastrichtian Horseshoe Canyon Formation. Additional species and specimens from other formations are sometimes classified as Ornithomimus, such as Ornithomimus samueli (alternately classified in the genera Dromiceiomimus or Struthiomimus) from the earlier, Campanian-age Dinosaur Park Formation of Alberta.

Paleoworld (Season 1)

Paleoworld (Season 1) is the first season of Paleoworld.

Struthiomimus

Struthiomimus (meaning "ostrich mimic", from the Greek στρούθειος/stroutheios meaning "of the ostrich" and μῖμος/mimos meaning "mimic" or "imitator") is a genus of ornithomimid dinosaurs from the late Cretaceous of North America. Ornithomimids were long-legged, bipedal, ostrich-like dinosaurs with toothless beaks. The type species, Struthiomimus altus, is one of the more common small dinosaurs found in Dinosaur Provincial Park; its abundance suggests that these animals were herbivores or omnivores rather than pure carnivores.

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.

Tototlmimus

Tototlmimus is an extinct genus of ornithomimid dinosaur. Its remains were found from the late Cretaceous Packard Formation, in the Sonora state, México.

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