Ankylosauria
Ankylosaurs | |||
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Collection of ankylosaurs. From top left to right: Liaoningosaurus, Edmontonia, Tianzhenosaurus, Gargoyleosaurus, Scolosaurus, Denversaurus, Gastonia, Borealopelta and Akainacephalus. | |||
Scientific classification | |||
Domain: | Eukaryota | ||
Kingdom: | Animalia | ||
Phylum: | Chordata | ||
Clade: | Dinosauria | ||
Clade: | †Ornithischia | ||
Clade: | †Thyreophora | ||
Clade: | † Eurypoda
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Clade: | †Ankylosauria Osborn, 1923 | ||
Subgroups | |||
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Synonyms[2] | |||
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Ankylosauria is a group of
Ankylosauria was first named by
Etymology
The name of this group of dinosaurs is associated with a number of anatomical features in which small and large bony shields fused together, completely covering their back and sides. On the skull these shields fused with the underlying bones, and the dorsal ribs fit snugly to the vertebrae. The Latin name Ankylosauria is derived from the Greek ἀγκύλος [ankylos] — "curved", "bent" with the anatomical meaning "hard" or "fused" and σαῦρος [sauros] — "lizard".[4]
In the 1908 description of the genus
Classification
Ankylosauria and
Thyreophora |
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A 2023 review of Thyreophora rejects the traditional Ankylosauridae-Nodosauridae split, instead finding "nodosaurids" to be referrable to three separate families:
Ankylosauria |
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Evolution
The origin of ankylosaurs is poorly understood, and only a few specimens from the Middle Jurassic are known.[10] The ancestry of ankylosaurs has long been sought among stegosaurs, the closest group to ankylosaurs compared to other dinosaurs. Currently, ankylosaurs are a close group of stegosaurs within the Eurypoda clade.[11] They are united by the presence of osteoderms in the skin, the narrow triangular skull of stegosaurs is similar to that of nodosaurids, and some similarity is found in the structure of the palate.[12] Since stegosaurs are known from the Middle Jurassic,[13] ankylosaurs are probably of the same age. They may have split up during the Aalenian period, more than 170 million years ago, but they were definitely in Africa by the Bathonian due to the presence of Spicomellus in Morocco.[14] There are no well-preserved remains of ankylosaurs of that age. An incomplete radius and ulna from the Isle of Skye in Scotland are known, the exact affiliation of which to ankylosaurs or stegosaurs is not established.[15] Most likely, ankylosaurs followed a different evolutionary path than stegosaurs, although it is unknown when and how they split off. In the latter, the osteoderms become raised, and the lateral protection disappears.[16] Ankylosaurs evolved towards the development of osteoderms on the surface of the skull, increased armor and further consolidation of the carapace,[17] which suggests that the ancestor of the carapace consisted of separate non-fused osteoderms.[18]
Paleobiology
Possible
Armor
All ankylosaurians had armor over much of their bodies, mostly scutes and nodules, with large spines in some cases. The scutes, or plates, are rectangular to oval objects organized in transverse (side to side) rows, often with keels on the upper surface. Smaller nodules and plates filled in the open spaces between large plates. In all three groups, the first two rows of plates tend to form a sort of half-ring around the neck; in nodosaurids, this comes from adjacent plates fusing with each other (and there is a third row as well), while ankylosaurids usually have the plates fused to the top of another band of bone. The skull has armor plastered on to it, including a distinctive piece on the outside-rear of the lower jaw.
Diet and feeding
Ankylosaurs were built low to the ground, typically one foot off the ground surface. They had small, triangular teeth that were loosely packed, similar to
Vocalization
In February 2023, scientists reported that the possible sounds ankylosaurs may have made were
See also
References
- ^ S2CID 244799975.
- ^ PMID 34966571.
- ^ Osborn, H. F. (1923). "Two Lower Cretaceous dinosaurs of Mongolia." American Museum Novitates, 95: 1–10.[1]
- ^ a b Ben Creisler, Dinosauria Translation and Pronunciation Guide. Archived 2011-11-11 at the Wayback Machine
- ^ Brown, B. 1908. The Ankylosauridae, a new family of armored dinosaurs from the Upper Cretaceous. American Museum of Natural History Bulletin 24: 187—201.
- ^ Carpenter, K., 1997, "Ankylosauria" pp. 16-20 in: P.J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs, Academic Press, San Diego
- ISBN 0-253-33964-2.
- .
- S2CID 258802937.
- ^ Arbour, V. M., Currie, P. J. 2016. Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs. Journal of Systematic Palaeontology 14 (5): 385—444.
- ^ Norman, D. B., Witmer, L. M. and Weishampel, D. B. 2004. Basal Thyreophora. Pр. 335—342. In D. B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria. Berkeley: University of California Press.
- ^ T.A. Tumanova, 1987, "Pantsirnyye dinozavry Mongolii", Trudy Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya 32: 1-80.
- ^ "PBDB".
- S2CID 237616095.
- ^ Clark, N.D.L. 2001. A thyreophoran dinosaur from the early Bajocian (Middle Jurassic) of the Isle of Skye, Scotland. Scottish Journal of Geology, 37: 19—26.
- ^ Coombs, W. P. 1978. The families of the ornithischian dinosaur order Ankylosauria. Journal of Paleontology 21: 143—170.
- ^ Maryanska, T. 1977. Ankylosauridae (Dinosauria) from Mongolia. Palaeontologia Polonica, 37: 85—151.
- ^ T.A. Tumanova, 1987, "Pantsirnyye dinozavry Mongolii", Trudy Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya 32: 1-80.
- ^ Tanke, D.H. and Brett-Surman, M.K. 2001. Evidence of Hatchling and Nestling-Size Hadrosaurs (Reptilia:Ornithischia) from Dinosaur Provincial Park (Dinosaur Park Formation: Campanian), Alberta, Canada. pp. 206-218. In: Mesozoic Vertebrate Life—New Research Inspired by the Paleontology of Philip J. Currie. Edited by D.H. Tanke and K. Carpenter. Indiana University Press: Bloomington. xviii + 577 pp.
- PMID 23557203.
- ^ Wilke, Carolyn (24 February 2023). "What Sounds Did Dinosaurs Make? - A new study of a fossilized ankylosaur suggests it could have uttered birdlike calls". The New York Times. Retrieved 26 February 2023.
- PMID 36792659.