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Centrosaurus

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Not to be confused withKentrosaurus.

Centrosaurus
Temporal range:Late Cretaceous(Campanian),76.5–75.5Ma
↓
Skull ROM 767 from Dinosaur Provincial Park
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: †Ornithischia
Clade: †Neornithischia
Clade: †Ceratopsia
Family: †Ceratopsidae
Subfamily: †Centrosaurinae
Clade: †Eucentrosaura
Tribe: †Centrosaurini
Genus: †Centrosaurus
Lambe1904
Species:
†C. apertus
Binomial name
†Centrosaurus apertus
Lambe1904
Synonyms
  • Monocloniusnasicornus
    Brown,1917
  • Monocloniusdawsoni
    Lambe,1902
  • Monocloniuslongirostris
    (Sternberg,1940)Kuhn,1964
  • Monocloniuscutleri
    Brown,1917
  • Centrosaurus flexus
    (Brown,1914)Lambe,1915
  • Eucentrosaurus apertus
    (Lambe,1904)Chure & McIntosh,1989

Centrosaurus(/ˌsɛntroʊˈsɔːrəs/SEN-troh-SOR-əs;lit. 'pointed lizard') is agenusofcentrosaurineceratopsiandinosaurfromCampanianageofLate CretaceousCanada.Their remains have been found in theDinosaur Park Formation,dating from 76.5 to 75.5 million years ago.[1]

Discovery and naming

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See also:Hilda mega-bonebed
Life restoration

The firstCentrosaurusremains were discovered and named by paleontologistLawrence Lambein strata along theRed Deer RiverinAlberta.The nameCentrosaurusmeans "pointed lizard" (fromGreekkentron,κέντρον,"point" andsauros,σαῦρος,"lizard" ) and refers to, the series of small hornlets placed along the margin of their frills, not the nasal horns (which were unknown when the dinosaur was named). The genus is not to be confused with thestegosaurKentrosaurus,the name of which is derived from the same Greek word.

Later, vast bonebeds ofCentrosauruswere found inDinosaur Provincial Park,also inAlberta.Some of these beds extend for hundreds of meters and contain thousands of individuals of all ages and all levels of completion. Scientists have speculated that the high density and number of individuals would be explained if they had perished while trying to cross a flooded river.[2]A discovery of thousands ofCentrosaurusfossils near the town ofHilda,Alberta,is believed to be the largest bed of dinosaur bones ever discovered. The area is now known as theHilda mega-bonebed.[3]

Because of the variation between species and even individual specimens of centrosaurines, there has been much debate over which genera and species are valid, particularly whetherCentrosaurusand/orMonocloniusare valid genera, undiagnosable, or possibly members of the opposite sex. In 1996,Peter Dodsonfound enough variation betweenCentrosaurus,Styracosaurus,andMonocloniusto warrant separate genera and thatStyracosaurusresembledCentrosaurusmore closely than either resembledMonoclonius.

The "Monocloniusnasicornus"skeleton

Dodson believed one species ofMonoclonius,M. nasicornus,may actually have been a femaleStyracosaurus.[4]His assessments have been partially followed, with other researchers not acceptingMonoclonius nasicornusas a femaleStyracosaurusorMonocloniusas a valid genus.[5]Whilesexual dimorphismhas been proposed for a more basal ceratopsian,Protoceratops,[6]there is no firm evidence for sexual dimorphism in any ceratopsid.[7][8][9]Others have synonymizedC. nasicornuswithC. apertus,[10]or considered it a separateCentrosaurusspecies:Centrosaurus nasicornus.[11]It has also been suggested as the direct ancestor ofStyracosaurus albertensis.[12]A 2014 study of changes during growth inCentrosaurusconcluded thatC. nasicornusis a junior synonym ofC. apertus,representing a middle growth stage.[13]

The speciesC. brinkmani,described in 2005, was moved to the new genusCoronosaurusin 2012.[14]

Description

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Size comparison with human

Centrosauruswere large dinosaurs, although not as large as some of their relatives, reaching 5–5.5 metres (16–18 ft) long and 2–2.5 metric tons (2.2–2.8 short tons) in body mass situated atop stocky limbs.[15][16]Like other centrosaurines,Centrosaurusbore a single large horn over their noses.[2]These horns curved forwards or backwards depending on the specimen. Skull ornamentation was reduced as animals aged.[13]The frill was relatively short compared to the total skull length and could grow to over half a meter (68.8 cm) long in the oldest and largest adults.[13]

Centrosaurusis distinguished by having two large hornlets which hook forwards over the frill. A pair of small upwards directed horns is also found over the eyes. The frills ofCentrosauruswere moderately long, with fairly largefenestraeand small hornlets along the outer edges.[2]

Classification

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A large hook from the back of a Centrosaurus frill. These hooks are diagnostic of the genus.
Complete skulls arranged inontogeneticorder

The genusCentrosaurusgives its name to the Centrosaurinae subfamily. Its closest relatives appear to beStyracosaurusandMonoclonius.It so closely resembles the latter of these that some paleontologists have considered them to represent the same animal.[2]Other members of the CentrosaurinaesubfamilyincludePachyrhinosaurus,[17][18]Avaceratops,[17]Einiosaurus,[18][19]Albertaceratops,[19]andAchelousaurus.[18]

Thecladogrampresented below represents a phylogenetic analysis by Chibaet al.(2017):[20]

Centrosaurinae

Paleobiology

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Cast of AMNH 5427,Museum of Victoria

Like otherceratopsids,the jaws ofCentrosauruswere adapted to shear through tough plant material. The discovery of gigantic bone beds ofCentrosaurusin Canada suggest that they were gregarious animals and could have traveled in large herds.[2]A bone bed composed ofCentrosaurusandStyracosaurusremains is known from theDinosaur Park Formationin what is now Alberta.[21]The mass deaths may have been caused by otherwise non-herding animals gathering around a waterhole during a drought.[22]Centrosaurusis found lower in the formation thanStyracosaurus,indicating thatCentrosauruswas displaced byStyracosaurusas the environment changed over time.[5]

Restoration of a herd swimming, as hypothesised bymega-bonebeds

The large frills and nasal horns of the ceratopsians are among the most distinctive facial adornments of all dinosaurs. Their function has been the subject of debate since the first horned dinosaurs were discovered. Common theories concerning the function of ceratopsian frills and horns include defense from predators, combat within the species, and visual display. A 2009 study ofTriceratopsandCentrosaurusskull lesions found that bone injuries on the skulls were more likely caused by intraspecific combat (horn-to-horn combat) rather than predatory attacks. The frills ofCentrosauruswere too thin to be used for defense against predators, although the thicker, solid frills ofTriceratopsmight have evolved to protect their necks. The frills ofCentrosauruswere most likely used "for species recognition and/or other forms of visual display".[23]

Paleopathology

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A specimen ofCentrosaurus apertusrecovered from Dinosaur Provincial Park in 1989 was discovered to have cripplingosteosarcomain its right fibula. Examination of the cancerous lesions in the bone suggest thecancerhad reached an aggressive stage. The cancer would have resulted in a severe limp that would have made the ceratopsian more vulnerable to predation. However, the fact that it was part of a herd allowed theCentrosaurusto survive much longer than would be expected for an animal infected with such severe disease. The individual itself is believed to have died from drowning in the flash flood that created theCentrosaurusbone bed where it was found. The specimen remains one of the few dinosaur specimens found with severe cancer.[24]

Paleobiogeography

[edit]
Skin impression of AMNH 5427

Thomas M. Lehman has observed thatCentrosaurusfossils haven't been found outside of southernAlbertaeven though they are among the most abundantJudithiandinosaurs in the region.[25]Large herbivores like the ceratopsians living in North America during the Late Cretaceous had "remarkably small geographic ranges" despite their large body size and high mobility.[25]This restricted distribution strongly contrasts with modernmammalianfaunas whose large herbivores' ranges "typical[ly]... span much of a continent."[25]

See also

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References

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  • Lambe, L. M. (1904). "On the squamoso-parietal crest of the horned dinosaursCentrosaurus apertusandMonoclonius canadensisfrom the Cretaceous of Alberta ".Proceedings and Transactions of the Royal Society of Canada.2.10(4): 1–9.
  1. ^Arbour, V.M., V. M.;Burns, M. E.; Sissons, R. L. (2009). "A redescription of the ankylosaurid dinosaurDyoplosaurus acutosquameusParks, 1924 (Ornithischia: Ankylosauria) and a revision of the genus ".Journal of Vertebrate Paleontology.29(4): 1117–1135.Bibcode:2009JVPal..29.1117A.doi:10.1671/039.029.0405.S2CID85665879.
  2. ^abcde"Centrosaurus." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B.The Age of Dinosaurs.Publications International, LTD. p. 135.ISBN0-7853-0443-6.
  3. ^Scientists find dino deathbed, signs of carnage. Edmonton Sun.http://www.edmontonsun.com/news/canada/2010/06/18/14439211.htmlArchived2010-06-22 at theWayback Machineretrieved 18 06 2010
  4. ^Dodson, P. (1996).The Horned Dinosaurs: A Natural History.Princeton University Press: Princeton, New Jersey, pp. 197–199.ISBN0-691-02882-6.
  5. ^abRyan, Michael J.; Evans, David C. (2005)."Ornithischian Dinosaurs".In Currie, Phillip J.; Koppelhus, Eva (eds.).Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed.Bloomington: Indiana University Press. pp.312–348.ISBN0-253-34595-2.
  6. ^Dodson, P. "Quantitative aspects of relative growth and sexual dimorphism inProtoceratops".Journal of Paleontology.50:929–940.
  7. ^Forster, C. A. (1990). The cranial morphology and systematics ofTriceratops,with a preliminary analysis of ceratopsian phylogeny. Ph.D. Dissertation. University of Pennsylvania, Philadelphia. 227 pp.
  8. ^Lehman, T. M. (1998). "A gigantic skull and skeleton of the horned dinosaurPentaceratops sternbergifrom New Mexico ".Journal of Paleontology.72(5): 894–906.Bibcode:1998JPal...72..894L.doi:10.1017/S0022336000027220.S2CID132807103.
  9. ^Sampson, S. D.; Ryan, M.J.; Tanke, D.H. (1997)."Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taphonomic and behavioral phylogenetic implications".Zoological Journal of the Linnean Society.121(3): 293–337.doi:10.1111/j.1096-3642.1997.tb00340.x.
  10. ^M.J. Ryan and D.C. Evans, 2005, "Ornithischian dinosaurs". In: P.J. Currie and E.B. Koppelhus (eds.),Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed.Indiana University Press, Bloomington pp 312-348
  11. ^Russell, L.S. (1930). "Upper Cretaceous dinosaur faunas of North America".Proceedings of the American Philosophical Society.69(4): 133–159.
  12. ^Paul, G.S., 2010,The Princeton Field Guide to Dinosaurs,Princeton University Press p. 261
  13. ^abcFrederickson, J. A.; Tumarkin-Deratzian, A. R. (2014)."Craniofacial ontogeny inCentrosaurus apertus".PeerJ.2:e252.doi:10.7717/peerj.252.PMC3933270.PMID24688836.
  14. ^Ryan, M. J.; Evans, D. C.; Shepherd, K. M.; Sues, H. (2012)."A new ceratopsid from the Foremost Formation (middle Campanian) of Alberta".Canadian Journal of Earth Sciences.49(10): 1251.Bibcode:2012CaJES..49.1251R.doi:10.1139/e2012-056.
  15. ^Paul, Gregory S. (2010).Princeton Field Guide to Dinosaurs.Princeton University Press.ISBN978-0-691-13720-9.
  16. ^Benson, Roger B. J.; Campione, Nicolás E.; Carrano, Matthew T.; Mannion, Philip D.; Sullivan, Corwin; Upchurch, Paul; Evans, David C. (2014-05-06)."Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage".PLOS Biology.12(5): e1001853.doi:10.1371/journal.pbio.1001853.ISSN1545-7885.PMC4011683.PMID24802911.
  17. ^abDodson, P. (1990). "On the status of the ceratopsidsMonocloniusandCentrosaurus".In Carpenter, K.; Currie, P.J. (eds.).Dinosaur Systematics: Perspectives and Approaches.Cambridge: Cambridge University Press. pp.231–243.ISBN0-521-36672-0.
  18. ^abcRyan, M.J.; A.P. Russell (2005). "A new centrosaurine ceratopsid from the Oldman Formation of Alberta and its implications for centrosaurine taxonomy and systematics".Canadian Journal of Earth Sciences.42(7): 1369–1387.Bibcode:2005CaJES..42.1369R.doi:10.1139/e05-029.hdl:1880/47001.S2CID128478038.
  19. ^abRyan, M.J. (2007). "A new basal centrosaurine ceratopsid from the Oldman Formation, southeastern Alberta".Journal of Paleontology.81(2): 376–396.doi:10.1666/0022-3360(2007)81[376:ANBCCF]2.0.CO;2.S2CID130607301.
  20. ^Kentaro Chiba; Michael J. Ryan; Federico Fanti; Mark A. Loewen; David C. Evans (2018). "New material and systematic re-evaluation ofMedusaceratops lokii(Dinosauria, Ceratopsidae) from the Judith River Formation (Campanian, Montana) ".Journal of Paleontology.92(2): 272–288.Bibcode:2018JPal...92..272C.doi:10.1017/jpa.2017.62.S2CID134031275.
  21. ^Eberth, David A.; Getty, Michael A. (2005)."Ceratopsian bonebeds: occurrence, origins, and significance".In Currie, Phillip J.; Koppelhus, Eva (eds.).Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed.Bloomington: Indiana University Press. pp.501–536.ISBN0-253-34595-2.
  22. ^Rogers, R. R. (1990). "Taphonomy of three dinosaur bone beds in the Upper Cretaceous Two Medicine Formation, northwestern Montana: Evidence for drought-related mortality".PALAIOS.5(5). SEPM Society for Sedimentary Geology: 394–41.Bibcode:1990Palai...5..394R.doi:10.2307/3514834.JSTOR3514834.
  23. ^Farke, A.A.; Wolff, E.D.S.;Tanke, D.H.(2009)."Evidence of Combat inTriceratops ".PLOS ONE.4(1): e4252.Bibcode:2009PLoSO...4.4252F.doi:10.1371/journal.pone.0004252.PMC2617760.PMID19172995.
  24. ^Ekhtiari, S.; Chiba, K.; Popovic, S.; Crowther, R.; Wohl, G.; Wong, A. K. O.; Tanke, D. H.; Dufault, D. M.; Geen, O. D.; Parasu, N.; Crowther, M. A.; Evans, D. C. (2020). "First case of osteosarcoma in a dinosaur: a multimodal diagnosis".The Lancet Oncology.21(8): 1021−1022.doi:10.1016/S1470-2045(20)30171-6.PMID32758461.S2CID225473251.
  25. ^abcLehman, T. M., 2001, Late Cretaceous dinosaur provinciality: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, pp. 310-328.
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