Anodontosaurus

Phylogeny: Dinosauria > Ornithischia > Genasauria > Thyreophora > Thyreophoroidea > Eurypoda > Ankylosauria > Euankylosauria > Ankylosauridae > Ankylosaurinae

Overview: Fossils now attributed to Anodontosaurus were first discovered in the mid-1910’s, in the Canadian province of Alberta. The recovered remains consisted of a skull, dermal armor, and some other parts of the skeleton, largely warped and crushed after fossilization. In 1929, the renowned American-Canadian paleontologist Charles M. Sternberg would establish Anodontosaurus as a new ankylosaur genus, using said fossils as the holotype. The creature’s generic name means “toothless lizard”, referring to how the referred skull and jaws lacked teeth. Some plate-like bones found with the jaws were mistakenly interpreted by Sternberg to have replaced its teeth. In reality, this animal actually did have teeth, but these were separated from the jaws by the same forces that damaged and warped the bones over time. These teeth, like those of other ankylosaurs, were simple, paired with a keratinous beak at the front of its jaws, used to snip branches and stems.

Anodontosaurus belonged to the ankylosaurid family of ankylosaurs, making it a close relative of a number of well known genera; Ankylosaurus and Euoplocephalus being examples. Like all of its kin, Anodontosaurus was extensively armored over its head, neck, back, and tail. The end of its tail was fused and tipped with a large club of fused bone, used to defend itself, but also to ward off rivals within its own species using side-to-side strikes, as fossil evidence shows. For many decades prior to the 2010’s, Anodontosaurus was often treated as the same animal as Euoplocephalus. In the 1970’s, a landmark study concluded it, as well as the genus Scolosaurus, were junior synonyms, as the name Euoplocephalus predates both. With most now finding Anodontosaurus and Scolosaurus to be fully distinct, but related genera, Euoplocephalus is known from much more limited fossils. Remains of Anodontosaurus come from the Horseshoe Canyon and Dinosaur Park formations.