fbpx
Wikipedia

Struthiomimus

January 01, 1970

Struthiomimus, meaning "ostrich-mimic" (from the Greek στρούθειος/stroutheios, or "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, smaller dinosaurs found in Dinosaur Provincial Park; their overall abundance—in addition to their toothless beak—suggests that these animals were mainly herbivorous or (more likely) omnivorous, rather than purely carnivorous. Similar to the modern extant ostriches, emus, and rheas (among other birds), ornithomimid dinosaurs likely lived as opportunistic omnivores, supplementing a largely plant-based diet with a variety of small mammals, reptiles, amphibians, insects, invertebrates, and anything else they could fit into their mouth, as they foraged.[1]

Struthiomimus
Temporal range: Late Cretaceous, 77–66 Ma
Cast of an S. altus skeleton, Rocky Mountain Dinosaur Resource Center
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: †Ornithomimosauria
Family: †Ornithomimidae
Genus: †Struthiomimus
Osborn, 1917
Species:
†S. altus
Binomial name
†Struthiomimus altus
(Lambe, 1902)

History of discovery edit

 
Cast of S. altus skeleton (specimen AMNH 5339), found in 1914

In 1901, Lawrence Lambe found some incomplete remains, holotype CMN 930, and named them Ornithomimus altus, placing them in the same genus as material earlier described by Othniel Charles Marsh in 1890. The specific name altus is from Latin, meaning "lofty" or "noble". However, in 1914, a nearly complete skeleton (AMNH 5339) was discovered by Barnum Brown at the Red Deer River site in Alberta, prompting O. altus to be described as the type genus of a new subgenus, Struthiomimus, by Henry Fairfield Osborn in 1917.[2] Dale Russell made Struthiomimus a full genus in 1972, at the same time referring several other specimens to it: AMNH 5375, AMNH 5385, AMNH 5421, CMN 8897, CMN 8902 and ROM 1790, all partial skeletons.[3] The type species, S. altus, is known from several skeletons and skulls,[4] In 1916 Osborn also renamed Ornithomimus tenuis Marsh 1890 into Struthiomimus tenuis.[2] This is today considered a nomen dubium. In 2016, ROM 1790 was made the holotype of a new genus and species, Rativates evadens.[5]

 
Skeletal diagram of S. altus specimen AMNH 5339

In subsequent years William Arthur Parks named four other species of Struthiomimus: Struthiomimus brevetertius Parks 1926,[6] Struthiomimus samueli Parks 1928,[7] Struthiomimus currellii Parks 1933 and Struthiomimus ingens Parks 1933.[8] These are today seen as either belonging to Dromiceiomimus or to Ornithomimus.

 
Cast of BHI 1266, which may be a Struthiomimus sedens specimen

In 1997 Donald Glut mentioned the name Struthiomimus lonzeensis.[9] This was probably a lapsus calami, a mistake for Ornithomimus lonzeensis (Dollo 1903) Kuhn 1965. Struthiomimus altus comes from the Late Campanian (Judithian age) Oldman Formation.[10]

A possible second species of Struthiomimus is known from the early Maastrichtian (Edmontonian age) Horseshoe Canyon Formation. Because dinosaur fauna show rapid turnover, it is likely that these younger Struthiomimus specimens represent a species distinct from S. altus, though no new name has been given to them.[10][11]

Additional Struthiomimus specimens from the lower Lance Formation and equivalents are larger (similar to Gallimimus in size) and tend to have straighter and more elongate hand claws, similar to those seen in Ornithomimus. One relatively complete Lance Formation specimen, BHI 1266, was originally referred to Ornithomimus sedens (named by Marsh in 1892[12]) and later classified as Struthiomimus sedens.[13] One 2015 paper by van der Reest et al. listed BHI 1266 as Ornithomimus sp.,[14] while another paper the same year considered the specimen Struthiomimus sp. pending a re-evaluation of both genera.[10]

Description edit

 
Life restoration of S. altus

The size of S. altus is estimated as about 4.3 metres (14 ft 1 in) long and 1.4 m (4 ft 7 in) tall at the hips, with a weight of around 150 kilograms (330 lb).[15] A larger specimen of S. altus is estimated to weigh about 233.8 kilograms (515 lb).[16] The specimens belonging to "S." sedens measured 4.8 metres (16 ft) long and weighed 350 kilograms (770 lb).[17] Struthiomimus had a build and skeletal structure typical of ornithomimids, differing from closely related genera like Ornithomimus and Gallimimus in proportions and anatomical details.[18]

 
Size comparison between S. altus and S. sedens

As with other ornithomimids, they had small slender heads on long necks (which made up about 40% of the length of the body in front of the hips).[4] Their eyes were large and their jaws were toothless. Their vertebral columns consisted of ten neck vertebrae, thirteen back vertebrae, six hip vertebrae, and about thirty-five tail vertebrae.[19] Their tails were relatively stiff and probably used for balance.[2] They had long slender arms and hands, with immobile forearm bones and limited opposability between the first finger and the other two.[20] As in other ornithomimids but unusually among theropods, the three fingers were roughly the same length, and the claws were only slightly curved; Henry Fairfield Osborn, describing a skeleton of S. altus in 1917, compared the arm to that of a sloth.[2] These might have been adaptations to support wing feathers.[21] It is likely it had feathers all over its body. Struthiomimus differed from close relatives only in subtle aspects of anatomy. The edge of the upper beak was concave in Struthiomimus, unlike Ornithomimus, which had straight beak edges.[11] Struthiomimus had longer hands relative to the humerus than other ornithomimids, with particularly long claws.[4] Their forelimbs were more robust than Ornithomimus.[11]

Classification edit

 
Original skull of RTMP 1990.026.0001 in A, C and E and restored in B, D and F

Struthiomimus is a member of the family Ornithomimidae, a group which also includes Anserimimus, Archaeornithomimus, Dromiceiomimus, Gallimimus, Ornithomimus, and Sinornithomimus.

Just as the fossil remains of Struthiomimus were incorrectly assigned to Ornithomimus, the larger group that Struthiomimus belongs to, the Ornithomimosauria, also underwent many changes over the years. For example, O.C. Marsh initially included Struthiomimus in the Ornithopoda, a large clade of dinosaurs not closely related to theropods.[22] Five years later, Marsh classified Struthiomimus in the Ceratosauria.[23][24] In 1891, Baur placed the genus within Iguanodontia.[25] As late as 1993, Struthiomimus was referred to Oviraptorosauria.[26] However, by the 1990s, there were numerous studies that placed Struthiomimus within Coelurosauria.[27][28][29][30]

Recognizing the difference between ornithomimids and other theropods, Rinchen Barsbold placed ornithomimids within their own infraorder, Ornithomimosauria, in 1976.[31] The constituency of Ornithomimidae and Ornithomimosauria varied with different authors. Paul Sereno, for example, used Ornithomimidae to include all ornithomimosaurians in 1998, but subsequently changed to a more exclusive definition (advanced ornithomimosaurs) within Ornithomimosauria,[32] a classification scheme that was adopted by other authors at the beginning of the current century.

The cladogram follows the 2011 analysis by Xu et al.:[33]

Paleobiology edit

In a 2001 study conducted by Bruce Rothschild and other paleontologists, fifty foot bones referred to Struthiomimus were examined for signs of stress fracture, but none were found.[34]

Struthiomimus was one of the first theropods envisioned from the outset as having a horizontal posture. Osborn in 1916 let the animal intentionally be depicted with an elevated tail.[2] This newer view created an image much more reminiscent of modern flightless birds, such as the ostrich to which this dinosaur's name refers, but would only much later be accepted for all theropods.

Diet edit

 
Reconstructed skull, Royal Belgian Institute of Natural Sciences, Brussels

There has been much discussion about the feeding habits of Struthiomimus. Because of its straight-edged beak, Struthiomimus may have been an omnivore. Some theories suggest that it may have been a shore-dweller and may have been a filter feeder.[19] Some paleontologists noted that it was more likely to be a carnivore because it is classified within the otherwise carnivorous theropod group.[3][35] This theory has never been discounted, but Osborn, who described and named the dinosaur, proposed that it probably ate buds and shoots from trees, shrubs and other plants,[18] using its forelimbs to grasp branches and its long neck to enable it accurately to select particular items. This herbivorous diet is further supported by the unusual structure of its hands. The second and third fingers were of equal length, could not function independently, and were probably bound together by skin as a single unit. The structure of the shoulder girdle did not allow a high elevation of the arm nor was optimised for a low reach. The hand could not be fully flexed for a grasping motion or spread for raking. This indicates that the hand was used as a "hook" or "clamp", for bringing branches or fern fronds at shoulder height within reach.[20] However, these adaptations might have been used for wing feather support instead.[21]

Speed edit

The legs (hind limbs) of Struthiomimus were long, powerful and seemingly well-suited to rapid running, much like an ostrich. The supposed speed of Struthiomimus was, in fact, its main defense from predators (although it may also have been able to lash out with its hind claws when cornered), such as the dromaeosaurids (e.g. Saurornitholestes and Dromaeosaurus) and tyrannosaurs (e.g. Daspletosaurus and Gorgosaurus), which lived at the same time. It is estimated to have been able to run at speeds between 50 and 80 km/h (31.1 and 49.7 mph).[36]

Paleoecology edit

 
Albertosaurus hunting Saurolophus with Struthiomimus in the foreground

Fossil remains of S. altus are only known definitively from the Oldman Formation, dated to between 78 and 77 million years ago during the Campanian stage of the late Cretaceous period.[10] A younger species (which has not yet been named), which apparently differed from S. altus in having longer, more slender hands, is known from several specimens found in the Horseshoe Canyon Formation and lower Lance Formation, between 69 and 67.5 million years ago (early Maastrichtian).[10]

See also edit

References edit

  1. ^ Barrett, Paul M (2005). "The diet of ostrich dinosaurs (Theropoda: Ornithomimosauria)". Palaeontology. 48 (2): 347–358. doi:10.1111/j.1475-4983.2005.00448.x.
  2. ^ a b c d e Osborn, Henry Fairfield (1917). "Skeletal adaptations of Ornitholestes, Struthiomimus, Tyrannosaurus" (PDF). Bulletin of the American Museum of Natural History. 35: 733–771.
  3. ^ a b Russell D (1972). "Ostrich dinosaurs from the Late Cretaceous of Western Canada". Canadian Journal of Earth Sciences. 9 (4): 375–402. Bibcode:1972CaJES...9..375R. doi:10.1139/e72-031.
  4. ^ a b c Currie, Philip J. (2005). "Theropods, Including Birds". In Currie, Phillip J.; Koppelhus, Eva (eds.). Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Bloomington: Indiana University Press. pp. 367–397. ISBN 978-0-253-34595-0.
  5. ^ McFeeters, Bradley; Ryan, Michael J.; Schröder-Adams, Claudia; Cullen, Thomas M. (2016). "A new ornithomimid theropod from the Dinosaur Park Formation of Alberta, Canada". Journal of Vertebrate Paleontology. 36 (6): e1221415. doi:10.1080/02724634.2016.1221415. S2CID 89242374.
  6. ^ Parks, W.A. (1926). "Struthiomimus brevetertius - A new species of dinosaur from the Edmonton Formation of Alberta". Transactions of the Royal Society of Canada. Series 3. 20 (4): 65–70.
  7. ^ Parks, W.A. (1928). "Struthiomimus samueli, a new species of Ornithomimidae from the Belly River Formation of Alberta". University of Toronto Studies, Geology Series. 26: 1–24.
  8. ^ Parks, W.A. (1933). "New species of dinosaurs and turtles from the Upper Cretaceous formations of Alberta". University of Toronto Studies, Geological Series. 34: 1–33.
  9. ^ Glut, D., 1997, Dinosaurs - The Encyclopedia. McFarland Press, Jefferson, NC. 1076 pp
  10. ^ a b c d e Claessens, L.; Loewen, Mark A. (2015). "A redescription of Ornithomimus velox Marsh, 1890 (Dinosauria, Theropoda)". Journal of Vertebrate Paleontology. 36: e1034593. doi:10.1080/02724634.2015.1034593. S2CID 85861590.
  11. ^ a b c Longrich, N (2008). "A new, large ornithomimid from the Cretaceous Dinosaur Park Formation of Alberta, Canada: Implications for the study of dissociated dinosaur remains". Palaeontology. 51 (4): 983–997. doi:10.1111/j.1475-4983.2008.00791.x.
  12. ^ Marsh, O.C. (1892). "Notice of new reptiles from the Laramie Formation". American Journal of Science. Series 3. 43 (257): 449–453. Bibcode:1892AmJS...43..449M. doi:10.2475/ajs.s3-43.257.449. S2CID 131291138.
  13. ^ Farlow, J.O., 2001, "Acrocanthosaurus and the maker of Comanchean large-theropod footprints", In: Tanke, Carpenter, Skrepnick and Currie (eds). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. pp. 408-427
  14. ^ Aaron, J.; van der Reest, Alexander P. Wolfe; Currie, Philip J. (2016). "[2015] 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.2015.10.004.
  15. ^ Paul, Gregory S. (1988). "Ornithomimus altus". Predatory Dinosaurs of the World. New York: Simon & Schuster. pp. 387–389. ISBN 978-0-671-61946-6.
  16. ^ Chinzorig, Tsogtbaatar; Cullen, Thomas; Phillips, George; Rolke, Richard; Zanno, Lindsay E. (2022-10-19). "Large-bodied ornithomimosaurs inhabited Appalachia during the Late Cretaceous of North America". PLOS One. 17 (10). e0266648. doi:10.1371/journal.pone.0266648. PMC 9581415.
  17. ^ Paul, Gregory S. (2010). The Princeton Field Guide to Dinosaurs. Princeton, NJ: Princeton University Press. p. 117. ISBN 978-0-691-13720-9.
  18. ^ a b Paul, Gregory S. (1988). "Genus Ornithomimus". Predatory Dinosaurs of the World. New York: Simon & Schuster. pp. 384–394. ISBN 978-0-671-61946-6.
  19. ^ a b Makovicky, Peter J.; Kobayashi, Yoshitsugu; Currie, Philip J. (2004). "Ornithomimosauria". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 137–150. ISBN 978-0-520-24209-8.
  20. ^ a b Nicholls, Elizabeth L.; Russell, Anthony P. (1985). "Structure and function of the pectoral girdle and forelimb of Struthiomimus altus (Theropoda: Ornithomimidae)". Palaeontology. 28: 643–677.
  21. ^ a b Zelenitsky, D. K.; Therrien, F.; Erickson, G. M.; Debuhr, C. L.; Kobayashi, Y.; Eberth, D. A.; Hadfield, F. (2012). "Feathered Non-Avian Dinosaurs from North America Provide Insight into Wing Origins". Science. 338 (6106): 510–514. Bibcode:2012Sci...338..510Z. doi:10.1126/science.1225376. PMID 23112330. S2CID 2057698.
  22. ^ Marsh, O. C. (1890). "Additional characters of the Ceratopsidae, with notice of new Cretaceous dinosaurs". American Journal of Science. 39 (233): 418–426. Bibcode:1890AmJS...39..418M. doi:10.2475/ajs.s3-39.233.418. S2CID 130812960.
  23. ^ Marsh, O. C. (1895). "On the affinities and classification of the dinosaurian reptiles". American Journal of Science. 50 (300): 483–498. Bibcode:1895AmJS...50..483M. doi:10.2475/ajs.s3-50.300.483. S2CID 130517438.
  24. ^ O. C. Marsh. 1896. The dinosaurs of North America. United States Geological Survey, 16th Annual Report, 1894-95 55:133-244
  25. ^ Baur, G. (1891). "Remarks on the reptiles generally called Dinosauria". The American Naturalist. 25 (293): 434–454. doi:10.1086/275329. S2CID 84575190.
  26. ^ Russell, D. A.; Dong, Z.-M. (1993). "The affinities of a new Theropod from the Alxa Desert, Inner Mongolia, People's Republic of China". Canadian Journal of Earth Sciences. 30 (10–11): 2107–2127. Bibcode:1993CaJES..30.2107R. doi:10.1139/e93-183.
  27. ^ J. A. Gauthier and K. Padian. 1985. Phylogenetic, functional, and aerodynamic analyses of the origin of birds and their flight. In M. K. Hecht, J. H. Ostrom, G. Viohl, and P. Wellnhofer (eds.), The Beginnings of Birds: Proceedings of the International Conference Archaeopteryx, Eichstätt 1984. Freunde des Jura-Museums Eichstätt, Eichstätt 185-197
  28. ^ F. E. Novas. 1992. The evolution of carnivorous dinosaurs. In J. L. Sanz and A. D. Buscalioni (eds.), The Dinosaurs and Their Environment Biotic: Proceedings of the Second Year of Paleontology in Cuenca. Institute "Juan Valdez", Cuenca, Argentina 126-163
  29. ^ Sereno, P. C.; Wilson, J. A.; Larsson, H. C. E.; Dutheil, D. B.; Sues, H.-D. (1994). "Early Cretaceous dinosaurs from the Sahara". Science. 266 (5183): 267–271. Bibcode:1994Sci...266..267S. doi:10.1126/science.266.5183.267. PMID 17771449. S2CID 36090994.
  30. ^ Makovicky, P. J.; Kobayashi, Y.; Currie, P. J. (2004). "Ornithomimosauria". In Weishampel, D. B.; Dodson, P.; Osmólska, H. (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 137–150. doi:10.1525/california/9780520242098.003.0008. ISBN 9780520242098.
  31. ^ R. Barsbold. 1976. K evolyutsii i sistematike pozdnemezozoyskikh khishchnykh dinozavrov [The evolution and systematics of late Mesozoic carnivorous dinosaurs]. In N. N. Kramarenko, B. Luvsandansan, Y. I. Voronin, R. Barsbold, A. K. Rozhdestvensky, B. A. Trofimov & V. Y. Reshetov (eds.), Paleontology and Biostratigraphy of Mongolia. The Joint Soviet-Mongolian Paleontological Expedition, 3:68-75 Transactions
  32. ^ Sereno, P.C. (1998). "A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 210 (1): 41–83. doi:10.1127/njgpa/210/1998/41.
  33. ^ Li Xu, Yoshitsugu Kobayashi, Junchang Lü, Yuong-Nam Lee, Yongqing Liu, Kohei Tanaka, Xingliao Zhang, Songhai Jia and Jiming Zhang (2011). "A new ornithomimid dinosaur with North American affinities from the Late Cretaceous Qiupa Formation in Henan Province of China". Cretaceous Research. 32 (2): 213–222. doi:10.1016/j.cretres.2010.12.004.{{cite journal}}: CS1 maint: multiple names: authors list (link)[dead link]
  34. ^ Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 331-336.
  35. ^ Osmólska H, Roniewicz E & Barsbold R (1972). "A new dinosaur, Gallimimus bullatus n. gen.,n. sp. (Ornithomimidae) from the Upper Cretaceous of Mongolia". Paleontol. Polonica. 27: 103–143.
  36. ^ Paul, regarding his comparative speed estimates, notes that "... just how swift is swift? In hard, precise measure, this can be a real can of worms; for just how fast living animals run is not well known." (Paul, G.S. 1988. Predatory Dinosaurs of the World. New York: Simon & Schuster.)

Further reading edit

  • Russell, D. A. (1969). "A new specimen of Stenonychosaurus from the Oldman Formation (Cretaceous) of Alberta". Canadian Journal of Earth Sciences. 6 (4): 595–612. Bibcode:1969CaJES...6..595R. doi:10.1139/e69-059.
  • Cranfield, I. (2004). The Illustrated Directory of Dinosaurs and other Prehistoric Creatures (pp. 30–33). Greenwich Editions. ISBN 0-86288-662-7.
  • Reisdorf, A.G.; Wuttke, M. (2012). "Re-evaluating Moodie's Opisthotonic-Posture Hypothesis in fossil vertebrates. Part I: Reptiles - The taphonomy of the bipedal dinosaurs Compsognathus longipes and Juravenator starki from the Solnhofen Archipelago (Jurassic, Germany)". Palaeobiodiversity and Palaeoenvironments. 92: 119–168. doi:10.1007/s12549-011-0068-y. S2CID 129785393.

External links edit

  •   Media related to Struthiomimus at Wikimedia Commons

January 01, 1970
struthiomimus, meaning, ostrich, mimic, from, greek, στρούθειος, stroutheios, ostrich, μῖμος, mimos, meaning, mimic, imitator, genus, ornithomimid, dinosaurs, from, late, cretaceous, north, america, ornithomimids, were, long, legged, bipedal, ostrich, like, di. Struthiomimus meaning ostrich mimic from the Greek stroy8eios stroutheios or of the ostrich and mῖmos 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 smaller dinosaurs found in Dinosaur Provincial Park their overall abundance in addition to their toothless beak suggests that these animals were mainly herbivorous or more likely omnivorous rather than purely carnivorous Similar to the modern extant ostriches emus and rheas among other birds ornithomimid dinosaurs likely lived as opportunistic omnivores supplementing a largely plant based diet with a variety of small mammals reptiles amphibians insects invertebrates and anything else they could fit into their mouth as they foraged 1 StruthiomimusTemporal range Late Cretaceous 77 66 Ma PreꞒ Ꞓ O S D C P T J K Pg N Cast of an S altus skeleton Rocky Mountain Dinosaur Resource Center Scientific classification Domain Eukaryota Kingdom Animalia Phylum Chordata Clade Dinosauria Clade Saurischia Clade Theropoda Clade Ornithomimosauria Family Ornithomimidae Genus StruthiomimusOsborn 1917 Species S altus Binomial name Struthiomimus altus Lambe 1902 Contents 1 History of discovery 2 Description 3 Classification 4 Paleobiology 4 1 Diet 4 2 Speed 5 Paleoecology 6 See also 7 References 8 Further reading 9 External linksHistory of discovery edit nbsp Cast of S altus skeleton specimen AMNH 5339 found in 1914 In 1901 Lawrence Lambe found some incomplete remains holotype CMN 930 and named them Ornithomimus altus placing them in the same genus as material earlier described by Othniel Charles Marsh in 1890 The specific name altus is from Latin meaning lofty or noble However in 1914 a nearly complete skeleton AMNH 5339 was discovered by Barnum Brown at the Red Deer River site in Alberta prompting O altus to be described as the type genus of a new subgenus Struthiomimus by Henry Fairfield Osborn in 1917 2 Dale Russell made Struthiomimus a full genus in 1972 at the same time referring several other specimens to it AMNH 5375 AMNH 5385 AMNH 5421 CMN 8897 CMN 8902 and ROM 1790 all partial skeletons 3 The type species S altus is known from several skeletons and skulls 4 In 1916 Osborn also renamed Ornithomimus tenuis Marsh 1890 into Struthiomimus tenuis 2 This is today considered a nomen dubium In 2016 ROM 1790 was made the holotype of a new genus and species Rativates evadens 5 nbsp Skeletal diagram of S altus specimen AMNH 5339 In subsequent years William Arthur Parks named four other species of Struthiomimus Struthiomimus brevetertius Parks 1926 6 Struthiomimus samueli Parks 1928 7 Struthiomimus currellii Parks 1933 and Struthiomimus ingens Parks 1933 8 These are today seen as either belonging to Dromiceiomimus or to Ornithomimus nbsp Cast of BHI 1266 which may be a Struthiomimus sedens specimen In 1997 Donald Glut mentioned the name Struthiomimus lonzeensis 9 This was probably a lapsus calami a mistake for Ornithomimus lonzeensis Dollo 1903 Kuhn 1965 Struthiomimus altus comes from the Late Campanian Judithian age Oldman Formation 10 A possible second species of Struthiomimus is known from the early Maastrichtian Edmontonian age Horseshoe Canyon Formation Because dinosaur fauna show rapid turnover it is likely that these younger Struthiomimus specimens represent a species distinct from S altus though no new name has been given to them 10 11 Additional Struthiomimus specimens from the lower Lance Formation and equivalents are larger similar to Gallimimus in size and tend to have straighter and more elongate hand claws similar to those seen in Ornithomimus One relatively complete Lance Formation specimen BHI 1266 was originally referred to Ornithomimus sedens named by Marsh in 1892 12 and later classified as Struthiomimus sedens 13 One 2015 paper by van der Reest et al listed BHI 1266 as Ornithomimus sp 14 while another paper the same year considered the specimen Struthiomimus sp pending a re evaluation of both genera 10 Description edit nbsp Life restoration of S altus The size of S altus is estimated as about 4 3 metres 14 ft 1 in long and 1 4 m 4 ft 7 in tall at the hips with a weight of around 150 kilograms 330 lb 15 A larger specimen of S altus is estimated to weigh about 233 8 kilograms 515 lb 16 The specimens belonging to S sedens measured 4 8 metres 16 ft long and weighed 350 kilograms 770 lb 17 Struthiomimus had a build and skeletal structure typical of ornithomimids differing from closely related genera like Ornithomimus and Gallimimus in proportions and anatomical details 18 nbsp Size comparison between S altus and S sedens As with other ornithomimids they had small slender heads on long necks which made up about 40 of the length of the body in front of the hips 4 Their eyes were large and their jaws were toothless Their vertebral columns consisted of ten neck vertebrae thirteen back vertebrae six hip vertebrae and about thirty five tail vertebrae 19 Their tails were relatively stiff and probably used for balance 2 They had long slender arms and hands with immobile forearm bones and limited opposability between the first finger and the other two 20 As in other ornithomimids but unusually among theropods the three fingers were roughly the same length and the claws were only slightly curved Henry Fairfield Osborn describing a skeleton of S altus in 1917 compared the arm to that of a sloth 2 These might have been adaptations to support wing feathers 21 It is likely it had feathers all over its body Struthiomimus differed from close relatives only in subtle aspects of anatomy The edge of the upper beak was concave in Struthiomimus unlike Ornithomimus which had straight beak edges 11 Struthiomimus had longer hands relative to the humerus than other ornithomimids with particularly long claws 4 Their forelimbs were more robust than Ornithomimus 11 Classification edit nbsp Original skull of RTMP 1990 026 0001 in A C and E and restored in B D and F Struthiomimus is a member of the family Ornithomimidae a group which also includes Anserimimus Archaeornithomimus Dromiceiomimus Gallimimus Ornithomimus and Sinornithomimus Just as the fossil remains of Struthiomimus were incorrectly assigned to Ornithomimus the larger group that Struthiomimus belongs to the Ornithomimosauria also underwent many changes over the years For example O C Marsh initially included Struthiomimus in the Ornithopoda a large clade of dinosaurs not closely related to theropods 22 Five years later Marsh classified Struthiomimus in the Ceratosauria 23 24 In 1891 Baur placed the genus within Iguanodontia 25 As late as 1993 Struthiomimus was referred to Oviraptorosauria 26 However by the 1990s there were numerous studies that placed Struthiomimus within Coelurosauria 27 28 29 30 Recognizing the difference between ornithomimids and other theropods Rinchen Barsbold placed ornithomimids within their own infraorder Ornithomimosauria in 1976 31 The constituency of Ornithomimidae and Ornithomimosauria varied with different authors Paul Sereno for example used Ornithomimidae to include all ornithomimosaurians in 1998 but subsequently changed to a more exclusive definition advanced ornithomimosaurs within Ornithomimosauria 32 a classification scheme that was adopted by other authors at the beginning of the current century The cladogram follows the 2011 analysis by Xu et al 33 Ornithomimidae Archaeornithomimus unnamed Sinornithomimus unnamed Anserimimus Gallimimus unnamed Qiupalong unnamed Struthiomimus OrnithomimusPaleobiology editIn a 2001 study conducted by Bruce Rothschild and other paleontologists fifty foot bones referred to Struthiomimus were examined for signs of stress fracture but none were found 34 Struthiomimus was one of the first theropods envisioned from the outset as having a horizontal posture Osborn in 1916 let the animal intentionally be depicted with an elevated tail 2 This newer view created an image much more reminiscent of modern flightless birds such as the ostrich to which this dinosaur s name refers but would only much later be accepted for all theropods Diet edit nbsp Reconstructed skull Royal Belgian Institute of Natural Sciences Brussels There has been much discussion about the feeding habits of Struthiomimus Because of its straight edged beak Struthiomimus may have been an omnivore Some theories suggest that it may have been a shore dweller and may have been a filter feeder 19 Some paleontologists noted that it was more likely to be a carnivore because it is classified within the otherwise carnivorous theropod group 3 35 This theory has never been discounted but Osborn who described and named the dinosaur proposed that it probably ate buds and shoots from trees shrubs and other plants 18 using its forelimbs to grasp branches and its long neck to enable it accurately to select particular items This herbivorous diet is further supported by the unusual structure of its hands The second and third fingers were of equal length could not function independently and were probably bound together by skin as a single unit The structure of the shoulder girdle did not allow a high elevation of the arm nor was optimised for a low reach The hand could not be fully flexed for a grasping motion or spread for raking This indicates that the hand was used as a hook or clamp for bringing branches or fern fronds at shoulder height within reach 20 However these adaptations might have been used for wing feather support instead 21 Speed edit The legs hind limbs of Struthiomimus were long powerful and seemingly well suited to rapid running much like an ostrich The supposed speed of Struthiomimus was in fact its main defense from predators although it may also have been able to lash out with its hind claws when cornered such as the dromaeosaurids e g Saurornitholestes and Dromaeosaurus and tyrannosaurs e g Daspletosaurus and Gorgosaurus which lived at the same time It is estimated to have been able to run at speeds between 50 and 80 km h 31 1 and 49 7 mph 36 Paleoecology edit nbsp Albertosaurus hunting Saurolophus with Struthiomimus in the foreground Fossil remains of S altus are only known definitively from the Oldman Formation dated to between 78 and 77 million years ago during the Campanian stage of the late Cretaceous period 10 A younger species which has not yet been named which apparently differed from S altus in having longer more slender hands is known from several specimens found in the Horseshoe Canyon Formation and lower Lance Formation between 69 and 67 5 million years ago early Maastrichtian 10 See also editTimeline of ornithomimosaur researchReferences edit Barrett Paul M 2005 The diet of ostrich dinosaurs Theropoda Ornithomimosauria Palaeontology 48 2 347 358 doi 10 1111 j 1475 4983 2005 00448 x a b c d e Osborn Henry Fairfield 1917 Skeletal adaptations of Ornitholestes Struthiomimus Tyrannosaurus PDF Bulletin of the American Museum of Natural History 35 733 771 a b Russell D 1972 Ostrich dinosaurs from the Late Cretaceous of Western Canada Canadian Journal of Earth Sciences 9 4 375 402 Bibcode 1972CaJES 9 375R doi 10 1139 e72 031 a b c Currie Philip J 2005 Theropods Including Birds In Currie Phillip J Koppelhus Eva eds Dinosaur Provincial Park A Spectacular Ancient Ecosystem Revealed Bloomington Indiana University Press pp 367 397 ISBN 978 0 253 34595 0 McFeeters Bradley Ryan Michael J Schroder Adams Claudia Cullen Thomas M 2016 A new ornithomimid theropod from the Dinosaur Park Formation of Alberta Canada Journal of Vertebrate Paleontology 36 6 e1221415 doi 10 1080 02724634 2016 1221415 S2CID 89242374 Parks W A 1926 Struthiomimus brevetertius A new species of dinosaur from the Edmonton Formation of Alberta Transactions of the Royal Society of Canada Series 3 20 4 65 70 Parks W A 1928 Struthiomimus samueli a new species of Ornithomimidae from the Belly River Formation of Alberta University of Toronto Studies Geology Series 26 1 24 Parks W A 1933 New species of dinosaurs and turtles from the Upper Cretaceous formations of Alberta University of Toronto Studies Geological Series 34 1 33 Glut D 1997 Dinosaurs The Encyclopedia McFarland Press Jefferson NC 1076 pp a b c d e Claessens L Loewen Mark A 2015 A redescription of Ornithomimus velox Marsh 1890 Dinosauria Theropoda Journal of Vertebrate Paleontology 36 e1034593 doi 10 1080 02724634 2015 1034593 S2CID 85861590 a b c Longrich N 2008 A new large ornithomimid from the Cretaceous Dinosaur Park Formation of Alberta Canada Implications for the study of dissociated dinosaur remains Palaeontology 51 4 983 997 doi 10 1111 j 1475 4983 2008 00791 x Marsh O C 1892 Notice of new reptiles from the Laramie Formation American Journal of Science Series 3 43 257 449 453 Bibcode 1892AmJS 43 449M doi 10 2475 ajs s3 43 257 449 S2CID 131291138 Farlow J O 2001 Acrocanthosaurus and the maker of Comanchean large theropod footprints In Tanke Carpenter Skrepnick and Currie eds Mesozoic Vertebrate Life New Research Inspired by the Paleontology of Philip J Currie pp 408 427 Aaron J van der Reest Alexander P Wolfe Currie Philip J 2016 2015 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 10 004 Paul Gregory S 1988 Ornithomimus altus Predatory Dinosaurs of the World New York Simon amp Schuster pp 387 389 ISBN 978 0 671 61946 6 Chinzorig Tsogtbaatar Cullen Thomas Phillips George Rolke Richard Zanno Lindsay E 2022 10 19 Large bodied ornithomimosaurs inhabited Appalachia during the Late Cretaceous of North America PLOS One 17 10 e0266648 doi 10 1371 journal pone 0266648 PMC 9581415 Paul Gregory S 2010 The Princeton Field Guide to Dinosaurs Princeton NJ Princeton University Press p 117 ISBN 978 0 691 13720 9 a b Paul Gregory S 1988 Genus Ornithomimus Predatory Dinosaurs of the World New York Simon amp Schuster pp 384 394 ISBN 978 0 671 61946 6 a b Makovicky Peter J Kobayashi Yoshitsugu Currie Philip J 2004 Ornithomimosauria In Weishampel David B Dodson Peter Osmolska Halszka eds The Dinosauria 2nd ed Berkeley University of California Press pp 137 150 ISBN 978 0 520 24209 8 a b Nicholls Elizabeth L Russell Anthony P 1985 Structure and function of the pectoral girdle and forelimb of Struthiomimus altus Theropoda Ornithomimidae Palaeontology 28 643 677 a b Zelenitsky D K Therrien F Erickson G M Debuhr C L Kobayashi Y Eberth D A Hadfield F 2012 Feathered Non Avian Dinosaurs from North America Provide Insight into Wing Origins Science 338 6106 510 514 Bibcode 2012Sci 338 510Z doi 10 1126 science 1225376 PMID 23112330 S2CID 2057698 Marsh O C 1890 Additional characters of the Ceratopsidae with notice of new Cretaceous dinosaurs American Journal of Science 39 233 418 426 Bibcode 1890AmJS 39 418M doi 10 2475 ajs s3 39 233 418 S2CID 130812960 Marsh O C 1895 On the affinities and classification of the dinosaurian reptiles American Journal of Science 50 300 483 498 Bibcode 1895AmJS 50 483M doi 10 2475 ajs s3 50 300 483 S2CID 130517438 O C Marsh 1896 The dinosaurs of North America United States Geological Survey 16th Annual Report 1894 95 55 133 244 Baur G 1891 Remarks on the reptiles generally called Dinosauria The American Naturalist 25 293 434 454 doi 10 1086 275329 S2CID 84575190 Russell D A Dong Z M 1993 The affinities of a new Theropod from the Alxa Desert Inner Mongolia People s Republic of China Canadian Journal of Earth Sciences 30 10 11 2107 2127 Bibcode 1993CaJES 30 2107R doi 10 1139 e93 183 J A Gauthier and K Padian 1985 Phylogenetic functional and aerodynamic analyses of the origin of birds and their flight In M K Hecht J H Ostrom G Viohl and P Wellnhofer eds The Beginnings of Birds Proceedings of the International Conference Archaeopteryx Eichstatt 1984 Freunde des Jura Museums Eichstatt Eichstatt 185 197 F E Novas 1992 The evolution of carnivorous dinosaurs In J L Sanz and A D Buscalioni eds The Dinosaurs and Their Environment Biotic Proceedings of the Second Year of Paleontology in Cuenca Institute Juan Valdez Cuenca Argentina 126 163 Sereno P C Wilson J A Larsson H C E Dutheil D B Sues H D 1994 Early Cretaceous dinosaurs from the Sahara Science 266 5183 267 271 Bibcode 1994Sci 266 267S doi 10 1126 science 266 5183 267 PMID 17771449 S2CID 36090994 Makovicky P J Kobayashi Y Currie P J 2004 Ornithomimosauria In Weishampel D B Dodson P Osmolska H eds The Dinosauria 2nd ed Berkeley University of California Press pp 137 150 doi 10 1525 california 9780520242098 003 0008 ISBN 9780520242098 R Barsbold 1976 K evolyutsii i sistematike pozdnemezozoyskikh khishchnykh dinozavrov The evolution and systematics of late Mesozoic carnivorous dinosaurs In N N Kramarenko B Luvsandansan Y I Voronin R Barsbold A K Rozhdestvensky B A Trofimov amp V Y Reshetov eds Paleontology and Biostratigraphy of Mongolia The Joint Soviet Mongolian Paleontological Expedition 3 68 75 Transactions Sereno P C 1998 A rationale for phylogenetic definitions with application to the higher level taxonomy of Dinosauria Neues Jahrbuch fur Geologie und Palaontologie Abhandlungen 210 1 41 83 doi 10 1127 njgpa 210 1998 41 Li Xu Yoshitsugu Kobayashi Junchang Lu Yuong Nam Lee Yongqing Liu Kohei Tanaka Xingliao Zhang Songhai Jia and Jiming Zhang 2011 A new ornithomimid dinosaur with North American affinities from the Late Cretaceous Qiupa Formation in Henan Province of China Cretaceous Research 32 2 213 222 doi 10 1016 j cretres 2010 12 004 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link dead link Rothschild B Tanke D H and Ford T L 2001 Theropod stress fractures and tendon avulsions as a clue to activity In Mesozoic Vertebrate Life edited by Tanke D H and Carpenter K Indiana University Press p 331 336 Osmolska H Roniewicz E amp Barsbold R 1972 A new dinosaur Gallimimus bullatus n gen n sp Ornithomimidae from the Upper Cretaceous of Mongolia Paleontol Polonica 27 103 143 Paul regarding his comparative speed estimates notes that just how swift is swift In hard precise measure this can be a real can of worms for just how fast living animals run is not well known Paul G S 1988 Predatory Dinosaurs of the World New York Simon amp Schuster Further reading editRussell D A 1969 A new specimen of Stenonychosaurus from the Oldman Formation Cretaceous of Alberta Canadian Journal of Earth Sciences 6 4 595 612 Bibcode 1969CaJES 6 595R doi 10 1139 e69 059 Cranfield I 2004 The Illustrated Directory of Dinosaurs and other Prehistoric Creatures pp 30 33 Greenwich Editions ISBN 0 86288 662 7 Reisdorf A G Wuttke M 2012 Re evaluating Moodie s Opisthotonic Posture Hypothesis in fossil vertebrates Part I Reptiles The taphonomy of the bipedal dinosaurs Compsognathus longipes and Juravenator starki from the Solnhofen Archipelago Jurassic Germany Palaeobiodiversity and Palaeoenvironments 92 119 168 doi 10 1007 s12549 011 0068 y S2CID 129785393 External links edit nbsp Media related to Struthiomimus at Wikimedia Commons Retrieved from https en wikipedia org w index php title Struthiomimus amp oldid 1213981055, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.