Is An Ostrich A Dinosaur

Extinct clade of theropod dinosaurs

Ornithomimosaurs Temporal range: Cretaceous, 140–66 Ma ^[one] PreꞒ Ꞓ O South D C P T J K Pg N

Collection of 7 ornithomimosaurs, clockwise from top left: Gallimimus, Anserimimus, Ornithomimus, Deinocheirus, Harpymimus, Struthiomimus and "Gallimimus mongoliensis"
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Maniraptoriformes
Clade:	†Ornithomimosauria Barsbold, 1976
Subgroups^[7]
† Haplocheirus? † Nedcolbertia ^[2] † Nqwebasaurus ^[3] † Thecocoelurus? † Valdoraptor? † Macrocheiriformes Cuesta et al., 2021 ^[4] † Harpymimus † Pelecanimimus † Shenzhousaurus † Ornithomimoidea Marsh, 1890 ^[5] † Arkansaurus † Hexing ^[6] † Kinnareemimus ^[1] † Deinocheiridae † Ornithomimidae
Synonyms
Arctometatarsalia Holtz, 1994

Ornithomimosauria ("bird-mimic lizards") are theropod dinosaurs which bore a superficial resemblance to the modern-day ostrich. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous Period of Laurasia (now Asia, Europe and N America), as well every bit Africa and possibly Australia.^[eight] The group first appeared in the Early Cretaceous and persisted until the Tardily Cretaceous. Primitive members of the grouping include Nqwebasaurus, Pelecanimimus, Shenzhousaurus, Hexing and Deinocheirus, the arms of which reached 2.iv m (8 feet) in length. More avant-garde 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 (run into classification below).

Description [edit]

The skulls of ornithomimosaurs were small, with large optics, above relatively long and slender necks. The most basal members of the taxon (such as Pelecanimimus and Harpymimus) had a jaw with small-scale teeth, while the later and more than derived species had a toothless neb.^[9] The fore limbs ("arms") were long and slender and bore powerful claws. The hind limbs were long and powerful, with a long pes and brusque, stiff toes terminating in hooflike claws. Ornithomimosaurs were probably among the fastest of all dinosaurs. Like other coelurosaurs, the ornithomimosaurian hide was feathered rather than scaly.

Feathers [edit]

Unambiguous evidence of feathers is known from Ornithomimus edmontonicus, of which there are multiple specimens preserving feather traces.^[10] Deinocheirus and Pelecanimimus have been speculated to exist feathered as well, the old due to the presence of a pygostyle,^[eleven] and the later due to possible impressions (otherwise taken to be collagen fibers). There is a argue on whether ornithomimids possessed the pennaceous feathers seen in Pennaraptora.^[12] Otherwise, a very ostrich-like plumage and feather range is known in 1 specimen of Ornithomimus.^[13]

Classification [edit]

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 big sized theropod dinosaurs), but every bit more theropod diversity was uncovered, their true relationships to other theropods started to resolve, and they were moved to the Coelurosauria. Recognizing the distinctiveness 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 every bit cladistic definitions began to appear for the groups in the 1990s.

In the early on 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 human foot bones were 'pinched' together, an adaptation for running. Holtz (1994) divers the clade Arctometatarsalia every bit "the showtime theropod to develop the arctometatarsalian foot and all of its descendants." This grouping included the Troodontidae, Tyrannosauroidea, and Ornithomimosauria. Holtz (1996, 2000) afterwards refined this definition to the branch-based "Ornithomimus and all theropods sharing a more recent mutual ancestor with Ornithomimus than with birds." Subsequently, the idea that all arctometatarsalian dinosaurs formed a natural group was abandoned by most paleontologists, including Holtz, equally 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 proper 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. Considering he had redefined Ornithomimosauria in a much narrower sense, a new term was made necessary inside his preferred terminology to denote the clade containing the sistergroups Ornithomimosauria and Alvarezsauridae — previously the latter had been contained within the old. However, this concept merely appeared on Sereno's Web site and has non nonetheless been officially published as a valid proper name.^[fourteen] "Ornithomimiformes" was identical in content to Holtz's Arctometatarsalia, every bit 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 proper noun has been changed very radically by Holtz.^[14]

Phylogeny [edit]

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 sectional sense began to abound in popularity when the possibility arose that alvarezsaurids might fall under Ornithomimosauria if an inclusive definition were adopted. Some other clade, Ornithomimiformes, was defined past Sereno (2005) as (Ornithomimus velox > Passer domesticus) and replaces the more than inclusive use of Ornithomimosauria when alvarezsaurids or another group are establish to be closer relatives of ornithomimosaurs than maniraptorans, with Ornithomimosauria redefined to include dinosaurs closer to Ornithomimus than to alvarezsaurids. Gregory South. Paul has proposed that Ornithomimosauria might exist a grouping of primitive, flightless birds, more advanced than Deinonychosauria and Oviraptorosauria.^[15]

The cladogram below follows an assay by Yuong-Nam Lee, Rinchen Barsbold, Philip J. Currie, Yoshitsugu Kobayashi, Hang-Jae Lee, Pascal Godefroit, François Escuillié & Tsogtbaatar Chinzorig. The analysis was published in 2014, and includes many ornithomimosaurian taxa.^[7]

The cladogram below follows the phylogenetic analysis by Scott Hartman and colleagues in 2019, which has included a vast majority of species and uncertain specimens, resulting in a novel phylogenetic arrangement.^[16]

Below is a cladogram past Serrano-Brañas et al., 2020, showing an analysis more in line with previous assumptions about ornithomimosaur classification.^[17]

Palaeobiology [edit]

Ornithomimosaurs probably acquired most of their calories from plants. Many ornithomimosaurs, including archaic species, accept been found with numerous gastroliths in their stomachs, characteristic of herbivores. Henry Fairfield Osborn suggested that the long, sloth-like "artillery" of ornithomimosaurs may have been used to pull down branches on which to feed, an idea supported by further study of their strange, claw-like easily.^[18] The sheer abundance of ornithomimids — they are the nigh common pocket-sized dinosaurs in North America — is consistent with the thought that they were plant eaters, as herbivores unremarkably outnumber carnivores in an ecosystem. However, they may have been omnivores that ate both plants and small animal prey.

Comparisons between the scleral rings of ii ornithomimosaur genera (Garudimimus and Ornithomimus) and modern birds and reptiles point that they may have been cathemeral, agile throughout the day at brusk intervals.^[19]

[edit]

Block containing 8 specimens of Sinornithomimus

Ornithomimosaurs are fairly well known for their gregarious life-styles. Some of the kickoff findings of ornithomimosaur bonebeds were reported from the Iren Dabasu Formation in 1993 past Charles W. Gilmore. The bonebed consisted of numerous individuals of Archaeornithomimus ranging from young to adult remains.^[20] Multiple specimens of Sinornithomimus were collected from a single monospecific bonebed with a considerable density of juvenile individuals—out of 14, xi were juveniles—, suggesting a gregarious beliefs for an increased protection from predators. The notable abundance of juveniles indicates a high mortality in them or that a large mass-mortality event of an entire group occurred, with more susceptibility in juveniles. Additionally, the increment in the tibia-femur ratio through the ontogenesis of Sinornithomimus may indicate higher cursorial capacities in adults than in juveniles.^[21] Moreover, and also contrary to the Sinornithomimus bonebed, a high concentration of ornithomimosaur specimens from the Bayshi Tsav locality was collected in a single multitaxic bonebed that is composed of at to the lowest degree five individuals at different ontogenetic stages. It is unlikely that the individuals of this bonebed represent a strategical social behaviour of a single species given the identification of at least two different taxa. Under this consideration, information technology is possible that a small pack of more 10 individuals of unlike ornithomimosaurian herds was travelling together in optimal areas to observe food resources, nesting sites or something else.^[22] ^[23]

References [edit]

^ ^a ^b Holtz, Thomas R. Jr. (2012) Dinosaurs: The Near Consummate, Up-to-Engagement Encyclopedia for Dinosaur Lovers of All Ages, Winter 2011 Appendix.
^ Brownstein CD. (2016) Redescription of Arundel formation Ornithomimosaur fabric and a reinterpretation of Nedcolbertia justinhofmanni as an "Ostrich Dinosaur": Biogeographic implications. PeerJ Preprints 4:e2308v1 https://doi.org/x.7287/peerj.preprints.2308v1
^ Choiniere, J. North.; Forster, C. A.; De Klerk, Westward. J. (2012). "New information on Nqwebasaurus thwazi, a coelurosaurian theropod from the Early Cretaceous (Hauteriverian?) Kirkwood Formation in Due south Africa". Periodical of African Earth Sciences. 71–72: 1–17. Bibcode:2012JAfES..71....1C. doi:10.1016/j.jafrearsci.2012.05.005.
^ Cuesta East, Vidal D, Ortega F, Shibata Grand, Sanz JL (2021). "Pelecanimimus (Theropoda: Ornithomimosauria) postcranial anatomy and the evolution of the specialized manus in Ornithomimosaurs and sternum in maniraptoriforms". Zoological Periodical of the Linnean Guild. 194 (2): 553–591. doi:10.1093/zoolinnean/zlab013.
^ Sereno, P. (2017). "Early Cretaceous ornithomimosaurs (Dinosauria: Coelurosauria) from Africa". Ameghiniana. 54 (5): 576–616. doi:ten.5710/AMGH.23.10.2017.3155. S2CID 134718338.
^ Jin Liyong, Chen Jun & Pascal Godefroit (2012). "A New Basal Ornithomimosaur (Dinosauria: Theropoda) from the Early Cretaceous Yixian Formation, Northeast China". In Godefroit, P. (ed.). Bernissart Dinosaurs and Early Cretaceous Terrestrial Ecosystems. Indiana University Press. pp. 467–487.
^ ^a ^b Lee, Y.-North.; Barsbold, R.; Currie, P.J.; Kobayashi, Y.; Lee, H.-J.; Godefroit, P.; Escuillié, F.; Chinzorig, T. (2014). "Resolving the long-standing enigmas of a behemothic ornithomimosaur Deinocheirus mirificus". Nature. 515 (7526): 1–4. Bibcode:2014Natur.515..257L. doi:x.1038/nature13874. PMID 25337880. S2CID 2986017.
^ Choiniere, Jonah N.; Forster, Catherine A.; De Klerk, William J. (2012). "New data on Nqwebasaurus thwazi, a coelurosaurian theropod from the Early Cretaceous Kirkwood Formation in Due south Africa". Journal of African Globe Sciences. 71–72: ane–17. Bibcode:2012JAfES..71....1C. doi:10.1016/j.jafrearsci.2012.05.005.
^ Last of the Dinosaurs: The Cretaceous Menses
^ van der Reest, A.J.; Wolfe, A.P.; Currie, P.J. (2016). "A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Germination, Alberta, Canada". Cretaceous Research. 58: 108–117. doi:ten.1016/j.cretres.2015.10.004.
^ Lee, Yuong-Nam; Barsbold, Rinchen; Currie, Philip J.; Kobayashi, Yoshitsugu; Lee, Hang-Jae; Godefroit, Pascal; Escuillié, François; Chinzorig, Tsogtbaatar (2014). "Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus". Nature. 515 (7526): 257–260. Bibcode:2014Natur.515..257L. doi:10.1038/nature13874. PMID 25337880. S2CID 2986017.
^ Foth, Christian; Tischlinger, Helmut; Rauhut, Oliver W. M. (2014). "New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers". Nature. 511 (7507): 79–82. Bibcode:2014Natur.511...79F. doi:10.1038/nature13467. PMID 24990749. S2CID 4464659.
^ Van Der Reest, Aaron J.; Wolfe, Alexander P.; Currie, Philip J. (2016). "A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Formation, Alberta, Canada". Cretaceous Research. 58: 108–117. doi:10.1016/j.cretres.2015.x.004.
^ ^a ^b Sereno, P. C. (2005). Stem Archosauria—TaxonSearch Archived 2009-01-15 at the Wayback Machine [version 1.0, 2005 Nov vii]
^ Paul, Grand.S. (2002). Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore: Johns Hopkins Academy Press.
^ Hartman, Southward.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). "A new paravian dinosaur from the Tardily Jurassic of Due north America supports a late acquisition of avian flying". PeerJ. 7: e7247. doi:10.7717/peerj.7247. PMC6626525. PMID 31333906.
^ Claudia Inés Serrano-Brañas; Belinda Espinosa-Chávez; S. Augusta Maccracken; Cirene Gutiérrez-Blando; Claudio de León-Dávila; José Flores Ventura (2020). "Paraxenisaurus normalensis, a large deinocheirid ornithomimosaur from the Cerro del Pueblo Formation (Upper Cretaceous), Coahuila, Mexico". Journal of South American Earth Sciences. 101: Commodity 102610. doi:ten.1016/j.jsames.2020.102610. S2CID 218968100.
^ Nicholls and Russell (1985).
^ Schmitz and Motani (2011)
^ Gilmore, C. W. (1933). "On the dinosaurian fauna of the Iren Dabasu Germination". Message of the American Museum of Natural History. 67 (2): 23−78. hdl:2246/355.
^ Kobayashi, Y.; Lü, J.-C. (2003). "A new ornithomimid dinosaur with gregarious habits from the Late Cretaceous of China" (PDF). Acta Palaeontologica Polonica. 48 (two): 235−259.
^ Chinzorig, T.; Kobayashi, Y.; Saneyoshi, G.; Tsogtbaatar, Chiliad.; Batamkhatan, Z.; Ryuji, T. (2017). "Multitaxic bonebed of two new ornithomimids (Theropoda, Ornithomimosauria) from the Upper Cretaceous Bayanshiree Formnation of southeastern Gobi desert, Mongolia". Periodical of Vertebrate Paleontology. Program and Abstracts: 97.
^ Tsogtbaatar, Thousand. (2019). Evolution, diversity, and disparity of ornithomimosaurs (Dinosauria: Theropoda) from the Upper Cretaceous of Mongolia (PDF) (PhD thesis). Hokkaido Academy. hdl:2115/74432.

External links [edit]