Ornithomimosauria
Encyclopedia
The Ornithomimosauria, ornithomimosaurs ("bird
-mimic lizards") or ostrich dinosaurs were theropod dinosaur
s which bore a superficial resemblance to modern ostrich
es. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous
Period of Laurasia
(now Asia
, Europe
and North America
). The group first appeared in the Early Cretaceous
and persisted until the Late Cretaceous
. Primitive members of the group include Pelecanimimus
, Shenzhousaurus
, Harpymimus
and probably the huge Deinocheirus
, the arms of which reached 2.4 m (8 feet) in length. More advanced species, members of the family Ornithomimidae, include Gallimimus
, Archaeornithomimus
, Anserimimus
, 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). An ornithomimid caudal vertebra has been discovered which has tooth drag marks attributed to Saurornitholestes
.
and Harpymimus
) had teeth, but most had toothless beak
s.
The fore limbs ('arms') were long and slender and bore powerful claws. The hind limbs were long and powerful, with a long foot and short, strong toes terminating in hooflike claws. Ornithomimosaurs were probably among the fastest of all dinosaurs. Like many other coelurosaurs, the ornithomimosaurian hide was probably feathered rather than scaly.
s in their stomachs, characteristic of herbivores. Henry Fairfield Osborn
suggested that the long, sloth-like 'arms' of ornithomimosaurs may have been used to pull down branches on which to feed, an idea supported by further study of their strange, hook-like hands. The sheer abundance of ornithomimids — they are the most common small dinosaurs in North America — is consistent with the idea that they were plant eaters, as herbivores usually outnumber carnivores in an ecosystem. However, they may have been omnivores that ate both plants and small animal prey.
The feeding habits of ornithomimids have been controversial.
In 2001 Norell et al. reported a specimen of Gallimimus (IGM 100/1133) and one of Ornithomimus (RTMP 95.110.1). These two fossil skulls had soft tissue preservation, and both had keratinous beaks with vertical grooves extending ventrally from the bony upper mandible. These structures are reminiscent of the lamellae seen in ducks, in which they function to strain small edible items like plants, forams, mollusks, and ostracods from the water. The authors further noted that ornithomimids were abundant in mesic environments, and rarer in more arid environments, suggesting that they may have depended on waterborne sources of food, possibly filter feeding. They noted that primitive ornithomimids had well developed teeth, while derived forms were edentulous and probably could not feed on large animals.
One later paper questioned the conclusions of Norell et al. Barrett (2005) noted that vertical ridges are seen on the inner surface of the beaks of strictly herbivorous turtles, and also the hadrosaurid Edmontosaurus. Barrett also offered calculations, estimating how much energy could be derived from filter feeding and the probable energy needs of an animal as big as Gallimimus. He concluded that herbivory was more likely.
s of two ornithomimosaur genera (Garudimimus
and Ornithomimus
) and modern birds and reptiles indicate that they may have been cathemeral
, active throughout the day at short intervals.
. Recognizing the distinctivness of ornithomimids compared to other dinosaurs, Rinchen Barsbold placed ornithomimids within their own infraorder, Ornithomimosauria, in 1976. The contents of Ornithomimidae and Ornithomimosauria varied from author to author as cladistic definitions began to appear for the groups in the 1990s.
In the early 1990s, prominent paleontologists such as Thomas R. Holtz Jr.
proposed a close relationship between theropods with an arctometatarsalian foot; that is, bipedal dinosaurs in which the upper foot bones were 'pinched' together, an adaptation for running. Holtz (1994) defined the clade
Arctometatarsalia as "the first theropod to develop the arctometatarsalian
pes and all of its descendants." This group included the Troodontidae
, Tyrannosauroidea
, and Ornithomimosauria. Holtz (1996, 2000) later refined this definition to the branch-based "Ornithomimus
and all theropods sharing a more recent common ancestor with Ornithomimus than with birds." Subsequently, the idea that all arctometatarsalian dinosaurs formed a natural group was abandoned by most paleontologists, including Holtz, as studies began to demonstrate that tyrannosaurids and troodontids were more closely related to other groups of coelurosaurs than they were to ornithomimosaurs. Since the strict definition of Arctometatarsalia was based on Ornithomimus, it became redundant with the name Ornithomimosauria under broad definitions of that clade, and the name Arctometatarsalia was mostly abandoned.
The paleontologist Paul Sereno
, in 2005, proposed the clade "Ornithomimiformes", defining them as all species closer to Ornithomimus edmontonicus than to Passer domesticus. Because he had redefined Ornithomimosauria in a much narrower sense, a new term was made necessary within his preferred terminology to denote the clade containing the sistergroups Ornithomimosauria and Alvarezsauridae — previously the latter had been contained within the former. However, this concept only appeared on Sereno's Web site and has not yet been officially published as a valid name.
"Ornithomimiformes" was identical in content to Holtz's Arctometatarsalia, as it has a very similar definition. While "Ornithomimiformes" is the newer group, Sereno rejected the idea that Arctometatarsalia should take precedence, because the meaning of the former name has been changed very radically by Holtz.
might fall under Ornithomimosauria if an inclusive definition were adopted. Another clade, Ornithomimiformes, was defined by Sereno (2005) as (Ornithomimus velox
> Passer domesticus
) and replaces the more inclusive use of Ornithomimosauria when alvarezsaurids or some other group are found to be closer relatives of ornithomimosaurs than maniraptora
ns, with Ornithomimosauria redefined to include dinosaurs closer to Ornithomimus than to alvarezsaurids. Gregory S. Paul
has proposed that Ornithomimosauria might be a group of primitive, flightless birds, more advanced than Deinonychosauria
and Oviraptorosauria
.
The cladogram
presented here follows the one recovered by Turner, Clarke, Ericson and Norell, 2007. Clade names follow definitions provided by Sereno, 2005.
Cladogram after Xu et al., 2011:
.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
-mimic lizards") or ostrich dinosaurs were theropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s which bore a superficial resemblance to modern ostrich
Ostrich
The Ostrich is one or two species of large flightless birds native to Africa, the only living member of the genus Struthio. Some analyses indicate that the Somali Ostrich may be better considered a full species apart from the Common Ostrich, but most taxonomists consider it to be a...
es. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period of Laurasia
Laurasia
In paleogeography, Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent from approximately...
(now Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
). The group first appeared in the Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
and persisted until the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
. Primitive members of the group include Pelecanimimus
Pelecanimimus
Pelecanimimus is a genus of basal ornithomimosaurian theropod dinosaur from the Early Cretaceous of Spain...
, Shenzhousaurus
Shenzhousaurus
Shenzhousaurus is a genus of basal ornithomimosaur from the Lower Cretaceous of China.The holotype was collected from near the bottom of the Yixian Formation at the Sihetun fossil site, Beipiao, western Liaoning Province...
, Harpymimus
Harpymimus
Harpymimus is a basal ornithomimosaurian theropod dinosaur from the Early Cretaceous Period of what is now Mongolia. Unlike later, more derived ornithomimosaurs, Harpymimus still possessed teeth, although they appear to have been restricted to the dentary of the lower jaw.-Discovery and naming:In...
and probably the huge Deinocheirus
Deinocheirus
Deinocheirus is a genus of large theropod dinosaur, possibly an ornithomimosaurian, which lived in what is now southern Mongolia, during the late Cretaceous Period .-Discovery and naming:...
, the arms of which reached 2.4 m (8 feet) in length. More advanced species, members of the family Ornithomimidae, include Gallimimus
Gallimimus
Gallimimus is a genus of ornithomimid theropod dinosaur from the late Cretaceous period Nemegt Formation of Mongolia. With individuals as long as , it was one of the largest ornithomimosaurs...
, Archaeornithomimus
Archaeornithomimus
Archaeornithomimus is a genus of ornithomimosaurian theropod dinosaur from the Late Cretaceous of China, 70 million years ago....
, Anserimimus
Anserimimus
Anserimimus 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...
, Struthiomimus
Struthiomimus
Struthiomimus is a genus of ornithomimid dinosaur from the late Cretaceous of Alberta, Canada. It was a long-legged, ostrich-like dinosaur.The bipedal Struthiomimus stood about long and tall at the hips and weighed around...
, and Ornithomimus
Ornithomimus
Ornithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...
. Some paleontologists, like Paul Sereno
Paul Sereno
Paul Callistus Sereno is an American paleontologist from the University of Chicago who discovered several new dinosaur species on several continents. He has conducted excavations at sites as varied as Inner Mongolia, Argentina, Morocco, and Niger...
, consider the enigmatic alvarezsaurids
Alvarezsauridae
Alvarezsauridae is an enigmatic family of small, long-legged running dinosaurs. Although originally thought to represent the earliest known flightless birds, a consensus of recent work suggests that they are primitive members of the Maniraptora. Other work found them to be the sister group to the...
to be close relatives of the ornithomimosaurs and place them together in the superfamily Ornithomimoidea (see classification below). An ornithomimid caudal vertebra has been discovered which has tooth drag marks attributed to Saurornitholestes
Saurornitholestes
Saurornitholestes is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Alberta, Montana and New Mexico....
.
Description
The skulls of ornithomimosaurs were small, with large eyes, above relatively long and slender necks. Some primitive species (such as PelecanimimusPelecanimimus
Pelecanimimus is a genus of basal ornithomimosaurian theropod dinosaur from the Early Cretaceous of Spain...
and Harpymimus
Harpymimus
Harpymimus is a basal ornithomimosaurian theropod dinosaur from the Early Cretaceous Period of what is now Mongolia. Unlike later, more derived ornithomimosaurs, Harpymimus still possessed teeth, although they appear to have been restricted to the dentary of the lower jaw.-Discovery and naming:In...
) had teeth, but most had toothless beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
s.
Diet
Ornithomimosaurs probably acquired most of their calories from plants. Many ornithomimosaurs, including primitive species, have been found with numerous gastrolithGastrolith
A gastrolith, also called a stomach stone or gizzard stones, is a rock held inside a gastrointestinal tract. Gastroliths are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. The grain size depends upon the size of the animal and the gastrolith's...
s in their stomachs, characteristic of herbivores. Henry Fairfield Osborn
Henry Fairfield Osborn
Henry Fairfield Osborn, Sr. ForMemRS was an American geologist, paleontologist, and eugenicist.-Early life and career:...
suggested that the long, sloth-like 'arms' of ornithomimosaurs may have been used to pull down branches on which to feed, an idea supported by further study of their strange, hook-like hands. The sheer abundance of ornithomimids — they are the most common small dinosaurs in North America — is consistent with the idea that they were plant eaters, as herbivores usually outnumber carnivores in an ecosystem. However, they may have been omnivores that ate both plants and small animal prey.
The feeding habits of ornithomimids have been controversial.
In 2001 Norell et al. reported a specimen of Gallimimus (IGM 100/1133) and one of Ornithomimus (RTMP 95.110.1). These two fossil skulls had soft tissue preservation, and both had keratinous beaks with vertical grooves extending ventrally from the bony upper mandible. These structures are reminiscent of the lamellae seen in ducks, in which they function to strain small edible items like plants, forams, mollusks, and ostracods from the water. The authors further noted that ornithomimids were abundant in mesic environments, and rarer in more arid environments, suggesting that they may have depended on waterborne sources of food, possibly filter feeding. They noted that primitive ornithomimids had well developed teeth, while derived forms were edentulous and probably could not feed on large animals.
One later paper questioned the conclusions of Norell et al. Barrett (2005) noted that vertical ridges are seen on the inner surface of the beaks of strictly herbivorous turtles, and also the hadrosaurid Edmontosaurus. Barrett also offered calculations, estimating how much energy could be derived from filter feeding and the probable energy needs of an animal as big as Gallimimus. He concluded that herbivory was more likely.
Daily activity patterns
Comparisons between the scleral ringSclerotic ring
Sclerotic rings are rings of bone found in the eyes of several groups of vertebrate animals, except for mammals and crocodilians. They can be made up of single bones or small bones together. They are believed to have a role in supporting the eye, especially in animals whose eyes are not spherical,...
s of two ornithomimosaur genera (Garudimimus
Garudimimus
Garudimimus is a basal ornithomimosaurian theropod dinosaur from the Upper Cretaceous of Mongolia.-Discovery and naming:...
and Ornithomimus
Ornithomimus
Ornithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...
) and modern birds and reptiles indicate that they may have been cathemeral
Cathemeral
A cathemeral organism is one that has sporadic and random intervals of activity during the day or night in which food is acquired, socializing with other organisms occurs, and any other activities necessary for livelihood are performed...
, active throughout the day at short intervals.
Classification
Named by O.C. Marsh in 1890, the family Ornithomimidae was originally classified as a group of "megalosaurs" (a "wastebasket taxon" containing any medium to large sized theropod dinosaurs), but as more theropod diversity was uncovered, their true relationships to other theropods started to resolve, and they were moved to the CoelurosauriaCoelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
. Recognizing the distinctivness of ornithomimids compared to other dinosaurs, Rinchen Barsbold placed ornithomimids within their own infraorder, Ornithomimosauria, in 1976. The contents of Ornithomimidae and Ornithomimosauria varied from author to author as cladistic definitions began to appear for the groups in the 1990s.
In the early 1990s, prominent paleontologists such as Thomas R. Holtz Jr.
Thomas R. Holtz Jr.
Thomas Richard Holtz, Jr., Ph.D. is a vertebrate palaeontologist and senior lecturer at the University of Maryland's Department of Geology. He has published extensively on the phylogeny, morphology, ecomorphology, and locomotion of terrestrial predators, especially on tyrannosaurids and other...
proposed a close relationship between theropods with an arctometatarsalian foot; that is, bipedal dinosaurs in which the upper foot bones were 'pinched' together, an adaptation for running. Holtz (1994) defined the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
Arctometatarsalia as "the first theropod to develop the arctometatarsalian
Arctometatarsalian
An arctometatarsalian organism is one in which the proximal part of the third metatarsal is pinched between metatarsals II and IV. The trait appears to be highly homoplastic, common in certain sorts of dinosaurs accustomed to running , to evenly transmit force to the metatarsals....
pes and all of its descendants." This group included the Troodontidae
Troodontidae
Troodontidae is a family of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and scrappy and they have therefore been allied, at various times, with many dinosaurian lineages...
, Tyrannosauroidea
Tyrannosauroidea
Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period...
, and Ornithomimosauria. Holtz (1996, 2000) later refined this definition to the branch-based "Ornithomimus
Ornithomimus
Ornithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...
and all theropods sharing a more recent common ancestor with Ornithomimus than with birds." Subsequently, the idea that all arctometatarsalian dinosaurs formed a natural group was abandoned by most paleontologists, including Holtz, as studies began to demonstrate that tyrannosaurids and troodontids were more closely related to other groups of coelurosaurs than they were to ornithomimosaurs. Since the strict definition of Arctometatarsalia was based on Ornithomimus, it became redundant with the name Ornithomimosauria under broad definitions of that clade, and the name Arctometatarsalia was mostly abandoned.
The paleontologist Paul Sereno
Paul Sereno
Paul Callistus Sereno is an American paleontologist from the University of Chicago who discovered several new dinosaur species on several continents. He has conducted excavations at sites as varied as Inner Mongolia, Argentina, Morocco, and Niger...
, in 2005, proposed the clade "Ornithomimiformes", defining them as all species closer to Ornithomimus edmontonicus than to Passer domesticus. Because he had redefined Ornithomimosauria in a much narrower sense, a new term was made necessary within his preferred terminology to denote the clade containing the sistergroups Ornithomimosauria and Alvarezsauridae — previously the latter had been contained within the former. However, this concept only appeared on Sereno's Web site and has not yet been officially published as a valid name.
"Ornithomimiformes" was identical in content to Holtz's Arctometatarsalia, as it has a very similar definition. While "Ornithomimiformes" is the newer group, Sereno rejected the idea that Arctometatarsalia should take precedence, because the meaning of the former name has been changed very radically by Holtz.
Taxonomy
- Infraorder Ornithomimosauria
- PelecanimimusPelecanimimusPelecanimimus is a genus of basal ornithomimosaurian theropod dinosaur from the Early Cretaceous of Spain...
(central SpainSpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
) - ShenzhousaurusShenzhousaurusShenzhousaurus is a genus of basal ornithomimosaur from the Lower Cretaceous of China.The holotype was collected from near the bottom of the Yixian Formation at the Sihetun fossil site, Beipiao, western Liaoning Province...
(northeastern ChinaChinaChinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
) - Kinnareemimus (ThailandThailandThailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
) - BeishanlongBeishanlongBeishanlong is a genus of giant ornithomimosaurian theropod dinosaur from the Early Cretaceous of China.-Discovery and naming:Three fossils of Beishanlong were in the early twenty-first century found in northwestern China at the White Ghost Castle site, in the province of Gansu...
(northeastern ChinaChinaChinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
) - Family DeinocheiridaeDeinocheirusDeinocheirus is a genus of large theropod dinosaur, possibly an ornithomimosaurian, which lived in what is now southern Mongolia, during the late Cretaceous Period .-Discovery and naming:...
- DeinocheirusDeinocheirusDeinocheirus is a genus of large theropod dinosaur, possibly an ornithomimosaurian, which lived in what is now southern Mongolia, during the late Cretaceous Period .-Discovery and naming:...
(MongoliaMongoliaMongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
)
- Deinocheirus
- Family GarudimimidaeGarudimimusGarudimimus is a basal ornithomimosaurian theropod dinosaur from the Upper Cretaceous of Mongolia.-Discovery and naming:...
- GarudimimusGarudimimusGarudimimus is a basal ornithomimosaurian theropod dinosaur from the Upper Cretaceous of Mongolia.-Discovery and naming:...
(MongoliaMongoliaMongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
)
- Garudimimus
- Family HarpymimidaeHarpymimusHarpymimus is a basal ornithomimosaurian theropod dinosaur from the Early Cretaceous Period of what is now Mongolia. Unlike later, more derived ornithomimosaurs, Harpymimus still possessed teeth, although they appear to have been restricted to the dentary of the lower jaw.-Discovery and naming:In...
- HarpymimusHarpymimusHarpymimus is a basal ornithomimosaurian theropod dinosaur from the Early Cretaceous Period of what is now Mongolia. Unlike later, more derived ornithomimosaurs, Harpymimus still possessed teeth, although they appear to have been restricted to the dentary of the lower jaw.-Discovery and naming:In...
(Mongolia)
- Harpymimus
- Superfamily Ornithomimoidea
- Family Ornithomimidae
- AnserimimusAnserimimusAnserimimus 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...
(Mongolia) - ArchaeornithomimusArchaeornithomimusArchaeornithomimus is a genus of ornithomimosaurian theropod dinosaur from the Late Cretaceous of China, 70 million years ago....
(China) - GallimimusGallimimusGallimimus is a genus of ornithomimid theropod dinosaur from the late Cretaceous period Nemegt Formation of Mongolia. With individuals as long as , it was one of the largest ornithomimosaurs...
(Mongolia) - OrnithomimusOrnithomimusOrnithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...
(AlbertaAlbertaAlberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, ColoradoColoradoColorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, New JerseyNew JerseyNew Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
, UtahUtahUtah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, WyomingWyomingWyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
) - QiupalongQiupalongQiupalong is a genus of ornithomimid dinosaur. Qiupalong lived during the late Cretaceous period in what is now Henan Province, China. It is known from a single partial skeleton recovered from the Qiupa Formation...
(eastern China) - SinornithomimusSinornithomimusSinornithomimus is a genus of ornithomimid theropod dinosaur found in 1997, in the early Late Cretaceous strata of the Ulansuhai Formation located at Alshanzuo Banner, Nei Mongol Autonomous Region, Northern China.-Discovery and naming:...
(Inner MongoliaInner MongoliaInner Mongolia is an autonomous region of the People's Republic of China, located in the northern region of the country. Inner Mongolia shares an international border with the countries of Mongolia and the Russian Federation...
) - StruthiomimusStruthiomimusStruthiomimus is a genus of ornithomimid dinosaur from the late Cretaceous of Alberta, Canada. It was a long-legged, ostrich-like dinosaur.The bipedal Struthiomimus stood about long and tall at the hips and weighed around...
(MontanaMontanaMontana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
and Alberta)
- Anserimimus
- Family Ornithomimidae
- Pelecanimimus
- ?TimimusTimimusTimimus is a genus of small coelurosaurian theropod dinosaur, which was originally identified as an ornithomimosaur, from the Early Cretaceous of Australia.-Discovery and species:...
, from the early Cretaceous (a femurFemurThe femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
from Dinosaur CoveDinosaur CoveNot to be confused with the children's book series of the same name.Dinosaur Cove in Victoria, Australia is a fossil bearing site in south-east of the continent where the Otway Ranges meet the sea to the west of Cape Otway, adjacent to Great Otway National Park .The inaccessible ocean-front cliffs...
in Victoria in southeastern AustraliaAustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
), is possibly an ornithomimosaurian.
Phylogeny
Ornithomimosauria has variously been used for the branch-based group of all dinosaurs closer to Ornithomimus than to birds, and in more restrictive senses. The more exclusive sense began to grow in popularity when the possibility arose that alvarezsauridsAlvarezsauridae
Alvarezsauridae is an enigmatic family of small, long-legged running dinosaurs. Although originally thought to represent the earliest known flightless birds, a consensus of recent work suggests that they are primitive members of the Maniraptora. Other work found them to be the sister group to the...
might fall under Ornithomimosauria if an inclusive definition were adopted. Another clade, Ornithomimiformes, was defined by Sereno (2005) as (Ornithomimus velox
Ornithomimus
Ornithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...
> Passer domesticus
House Sparrow
The House Sparrow is a bird of the sparrow family Passeridae, found in most parts of the world. One of about 25 species in the genus Passer, the House Sparrow occurs naturally in most of Europe, the Mediterranean region, and much of Asia...
) and replaces the more inclusive use of Ornithomimosauria when alvarezsaurids or some other group are found to be closer relatives of ornithomimosaurs than maniraptora
Maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Deinonychosauria, Oviraptorosauria and Therizinosauria. Ornitholestes and the Alvarezsauroidea...
ns, with Ornithomimosauria redefined to include dinosaurs closer to Ornithomimus than to alvarezsaurids. Gregory S. Paul
Gregory S. Paul
Gregory Scott Paul is a freelance researcher, author and illustrator who works in paleontology, and more recently has examined sociology and theology. He is best known for his work and research on theropod dinosaurs and his detailed illustrations, both live and skeletal...
has proposed that Ornithomimosauria might be a group of primitive, flightless birds, more advanced than Deinonychosauria
Deinonychosauria
The Deinonychosauria were a clade of coelurosaurian theropod dinosaurs from the Late Jurassic and Cretaceous periods. These omnivores and carnivores are known for their switchblade-like second toe claws and for displaying numerous bird-like characteristics. The clade has been divided into two...
and Oviraptorosauria
Oviraptorosauria
Oviraptorosaurs are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot - like skulls, with or without bony crests atop the head...
.
The cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
presented here follows the one recovered by Turner, Clarke, Ericson and Norell, 2007. Clade names follow definitions provided by Sereno, 2005.
Cladogram after Xu et al., 2011:
Paleopathology
An ornithomimid caudal vertebra has been discovered that has tooth drag marks attributed to Saurornitholestes. A specimen from an unidentified ornithomimid shows a pathologic toe bone whose far end is "mushroomed" compared to those of healthy specimens.Reproduction
Neonate sized ornithomimid fossils have been documented in the scientific literatureScientific literature
Scientific literature comprises scientific publications that report original empirical and theoretical work in the natural and social sciences, and within a scientific field is often abbreviated as the literature. Academic publishing is the process of placing the results of one's research into the...
.
External links
- Khalaf-von Jaffa, Norman Ali Bassam Ali Taher (2006). Ornithomimid Dinosaur Tracks from Beit Zeit, West of Jerusalem, Palestine. Gazelle: The Palestinian Biological Bulletin. Number 56, August 2006. pp. 1–7.