Triceratops

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Triceratops
Temporal range: Upper Cretaceous 68–66 mya
Scientific classification
Kingdom: Animalia
Class: Sauropsida
Superorder: Dinosauria
Order: Ornithischia
Suborder: Cerapoda
Infraorder: Ceratopsia
Family: Ceratopsidae
Genus: Triceratops
Marsh, 1889
T. horridus skeleton mounted with modern limb-posture, Natural History Museum of Los Angeles County
Triceratops compared in size with a human

Triceratops was a herbivorous ceratopsid dinosaur from the late Cretaceous. Its name came from having three horns on its head (Greek tri = three + keratops = horned face). They were mainly found in North America. They were about 29 feet long, 9 feet tall, and probably weighed around 5,400 kg (12,000 lb).

Triceratops was a low browser with a premaxilla beak in front of its close-set grinding teeth. Its defence had to stand up to attacks from taller theropods, hence the shield which covered its neck. Holes made by teeth have been found on the bony frill behind the horns, and on the sacrum (the part of the spine above the pelvis).

Many fossils of Triceratops have been collected since the genus was first described in 1889. There is at least one complete individual skeleton.[1] Paleontologist John Scannella observed: "It is hard to walk out into the Hell Creek Formation and not stumble upon a Triceratops weathering out of a hillside." Forty-seven complete or partial skulls were discovered in just that area during the decade 2000–2010.[2] Specimens representing life stages from hatchling to adult have been found.[3]

Size[change | edit source]

Individual Triceratops were about 7.9 to 9.0 m (26.0–29.5 ft) in length, 2.9 to 3.0 m (9.5–9.8 ft) in height,[4][5] and 6.1–12.0 tonnes (13,000–26,000 lb) in weight.[6]

The most distinctive feature is their large skull, among the largest of all land animals. The largest known skull (specimen BYU 12183) is estimated to have been 2.5 metres (8.2 ft) in length when complete, and could reach almost a third of the length of the entire animal. It bore a single horn on the snout, above the nostrils, and a pair of horns approximately 1 m (3 ft) long, with one above each eye. Most other ceratopsids had large holes (fenestrae) in their frills, while those of Triceratops were noticeably solid.

Limbs[change | edit source]

Triceratops species were sturdy, with strong limbs and short three-hoofed hands and four-hoofed feet.[1]

The posture of these dinosaurs has long been the subject of some debate. Originally, it was believed that the front legs of the animal had to be sprawling at angles from the thorax, in order to better bear the weight of the head. This stance can be seen in paintings by Charles Knight and Rudolph Zallinger. However, evidence of trackways, and reconstructions of skeletons show that Triceratops and other ceratopsids had an upright stance during normal locomotion, with the elbows flexed and slightly bowed out. The stance was intermediate between fully upright and fully sprawling, similar the modern rhinoceros.[1][7][8][9]

References[change | edit source]

  1. 1.0 1.1 1.2 Fujiwara, S.-I. (2009). "A Reevaluation of the manus structure in Triceratops (Ceratopsia: Ceratopsidae)". Journal of Vertebrate Paleontology 29 (4): 1136–1147. doi:10.1671/039.029.0406.
  2. "Morph-osaurs: How shape-shifting dinosaurs deceived us - life - 28 July 2010". New Scientist. doi:10.1080/02724634.2010.483632. http://www.newscientist.com/article/mg20727713.500-morphosaurs-how-shapeshifting-dinosaurs-deceived-us.html?full=true. Retrieved 2010-08-03.
  3. Lambert D. (1993). The Ultimate Dinosaur Book. Dorling Kindersley, New York. pp. 152–167. ISBN 1-56458-304-X.
  4. "T Dinosaurs Page 2". DinoDictionary.com. http://www.dinodictionary.com/dinos_tpg2.asp. Retrieved 2010-08-03.
  5. "Triceratops in the Natural History Museum's Dino Directory". Internt.nhm.ac.uk. http://internt.nhm.ac.uk/jdsml/nature-online/dino-directory/detail.dsml?Genus=Triceratops. Retrieved 2010-08-03.
  6. Alexander, R.M. (1985). "Mechanics of posture and gait of some large dinosaurs". Zoological Journal of the Linnean Society 83: 1–25. doi:10.1111/j.1096-3642.1985.tb00871.x.
  7. Christiansen, P.; Paul, G.S. (2001). "Limb bone scaling, limb proportions, and bone strength in neoceratopsian dinosaurs". Gaia 16: 13–29. http://gspauldino.com/pdfs/GaiaNeoceratopsian.pdf.
  8. Thompson, S.; and Holmes, R. (2007). "Forelimb stance and step cycle in Chasmosaurus irvinensis (Dinosauria: Neoceratopsia)". Palaeontologia Electronica 10 (1): 17 p.. http://palaeo-electronica.org/2007_1/step/index.html.
  9. Rega, E.; Holmes, R.; and Tirabasso, A. (2010). "Habitual locomotor behavior inferred from manual pathology in two Late Cretaceous chasmosaurine ceratopsid dinosaurs, Chasmosaurus irvinensis (CMN 41357) and Chasmosaurus belli (ROM 843)". In Ryan, Michael J.; Chinnery-Allgeier, Brenda J.; and Eberth, David A. (editors.). New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium. Bloomington and Indianapolis: Indiana University Press. pp. 340–354. ISBN 978-0-253-35358-0.

Other websites[change | edit source]