The skull of Ankylosaurus was low and somewhat triangular, narrowing from the base up to the snout. Crests above the eye sockets merged into a pair of upper squamosal horns, and below these there were a pair of jugal horns that pointed down and to the sides.
As in other ankylosaurids, this species has been found with large osteoderms or scutes that would have been imbedded in its skin. However, these scutes have never been found in articulation, so their arrangement on its body can only be inferred based on the arrangement in similar related species. The walls of Ankylosaurus osteoderms were relatively thin, and the underside was hollow. Additionally, those thought to cover the body were relatively flat, though they had a small keel at the margin. Ankylosaurus also had small armor plates on its neck, though the remains of these pieces are fragmentary so their exact positioning is similarly uncertain.
The tail of Ankylosaurus ended in a large club, though unfortunately this is only known from a single specimen. It is known that in other ankylosaurs there was a degree of individual variation in club shape, so this is likely the case with Ankylosaurus as well. The 'handle' of the club was formed by the posterior seven caudal vertebrae, which were in direct contact with each other. These were sometimes coossified, making them completely immobile. There were also ossified tendons that attached to the vertebrae in front of the club, and these combined features added further strength (Arbour and Currie, 2015).
As with other ornithischian dinosaurs, Ankylosaurus was an herbivore. Its wide muzzle and relatively short stature made it well-adapted for non-selective browsing of low vegetation. One relative of Ankylosaurus was found with large preserved paraglossalia (cartilages or triangular bones found within the tongue), and these showed signs of significant muscular stress - this feature is thought to be common in all ankylosaurs, including Ankylosaurus. Some have suggested that the low replacement rate and size of ankylosaur teeth relied primarily on muscular tongues and hyobranchia (tongue bones) when feeding. Some extant salamanders have tongue bones similar to those found in ankylosaurs, and these species use their prehensile tongues to acquire their food (Hill et al., 2015). This research has suggested a varied diet for Ankylosaurus and its relatives that would have consisted of tough leaves and pulp-filled fruits. Personally, I can imagine the actual feeding mechanic working similar to that of a modern herbivorous turtle - the tongue could be extended as the mouth opened to "hold" the food steady just long enough for the animal to close its mouth and start orally processing the food. It's a bit hard to explain verbally, but you will see what I mean if you watch tortoises feeding in a video.
Well, I hope this gives you a bit more knowledge about the fascinating dinosaur that is Ankylosaurus!
Acknowledgements:
Paul, Gregory S. 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 234.
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 (8): 961-86.
Arbour, V.C.; Currie, P.J. 2015. Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs. Journal of Systematic Palaeontology. 1-60.
Hill, R. V.; D'Emic, M.D.; Bever, G.S.; Norell, M.A. 2015. A complex hyobranchial apparatus in a Cretaceous dinosaur and the antiquity of avian paraglossalia. Zoological Journal of the Linnean Society 175 (4).
No comments:
Post a Comment