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Ankylosaurus palaeocritti.jpg
Life recnstruction of Ankylosaurus by Nobu Tamura.
Vital statistics
Scientific Name Ankylosaurus magniventris
Length 8 metres
Height 2 metres at the hip
Weight 6 tonnes
Diet Herbivorous
Lived 65 million years ago
Range Montana, USA

Ankylosaurus ("fused lizard"[1]) was a ankylosaur dinosaur from the Late Cretaceous period. 


Ankylosaurus was the largest known member of the ankylosaur family, estimated to have measured 8 to 9 meters in length[2] and have weighed about 6 tonnes.[3] It had a small, triangular skull filled with leaf-shaped teeth for eating food.[4]

Armor and tail club[]

The most obvious feature of Ankylosaurus is its prominent armor, which was made up of many bony scutes embedded into the skin. In life, they would have been covered by a layer of keratin. Similar armor is found in modern crocodilians and armadillos, where it is used to protect the animal from predators.

The animal's tail was tipped by several large scutes which were fused to the last few vertebrae. They formed a large club that would be supported by muscular tendons when Ankylosaurus was alive. It is commonly assumed that this club was used as a defensive weapon against predators such as Tyrannosaurus. Whether this was truly the case remains unknown, but it is supported by several studies.[5]


Ankylosaurus is part of the family Ankylosauridae, and was indeed named as its type genus. Its exact placement within the group is unknown, but it may or may not be closely related to Euoplocephalus.[6]


The first specimen of Ankylosaurus was discovered by Barnum Brown in 1906, in the Hell Creek Formation of Montana. He described it in 1908 as Ankylosaurus magniventris.[7] No complete skeleton has ever been found, but isolated bones and teeth have been collected over the years.


The regions in which Ankylosaurus fossils have been found were floodplains during the Late Cretaceous, indicating a subtropical environment.[8]



Ankylosaurus was a herbivore. Due to its teeth and the shape of its mouth, it was likely a grazer that fed on all types of plants.[9]

In popular culture[]

Ankylosaurus is one of the more recognizable prehistoric creatures due to its armor, and since its reconstruction at the 1964 World's Fair was displayed, has become quite popular. It has featured in many dinosaur documentaries such as Walking with Dinosaurs and has made small cameo appearances in Jurassic Park III and Doctor Who.


  1. Creisler, Ben (July 7, 2003). "Dinosauria Translation and Pronunciation Guide A". Archived from the original on August 18, 2010. Retrieved September 3, 2010.
  2. Vickaryous, M.K., Maryanska, T., & Weishampel, D.B. 2004. Ankylosauria. In: Weishampel, D.B., Dodson, P., & Osmólska, H. (Eds.). The Dinosauria (2nd edition). Berkeley: University of California Press. Pp. 363-392.
  3. Coombs, Walter P. (December 1978). "Theoretical Aspects of Cursorial Adaptations in Dinosaurs". The Quarterly Review of Biology 53 (4): 393–418. doi:10.1086/410790.
  4. Carpenter, Kenneth (2001). The Armored Dinosaurs. Indiana University Press. p. 255. ISBN 0-253-33964-2.
  5. Arbour, V. M. (2009) "Estimating Impact Forces of Tail Club Strikes by Ankylosaurid Dinosaurs" PLoS ONE 4(8): e6738. [1] doi:10.1371/journal.pone.0006738
  6. Carpenter, K. 2001. Phylogenetic analysis of the Ankylosauria. In: Carpenter, K. (Ed.). The Armored Dinosaurs. Bloomington: Indiana University Press. Pp. 454–483.
  7. Brown, B. 1908. The Ankylosauridae, a new family of armored dinosaurs from the Upper Cretaceous. Bulletin of the American Museum of Natural History 24: 187–201.
  8. Lofgren, D.F. 1997. Hell Creek Formation. In: Currie, P.J. & Padian, K. (Eds.). The Encyclopedia of Dinosaurs. San Diego: Academic Press. Pp. 302-303.
  9. Carpenter, K. 2004. Redescription of Ankylosaurus magniventris Brown 1908 (Ankylosauridae) from the Upper Cretaceous of the Western Interior of North America. Canadian Journal of Earth Sciences 41: 961–986.