Animantarx ramaljonesi was a nodosaurid from Cretaceous Western North America. Like other nodosaurs, it was heavily armoured but lacked a tail club. Yet with a name meaning “Living Fortress” it’s clear that, however small, Animantarx’s spiky neck armour would have made it just a bit too much effort for many predators.
Fossils in the Cedar Mountain Formation are often slightly radioactive, and Animantarx was the first dinosaur to be discovered through technology, following a radiological survey performed in the area. Animantarx was completely buried beneath the surface, but the radioactivity of its fossilized bones set off the scanner! That being sad, not much of its skeleton was found. Only the lower jaw, the back half of the skull, neck and back vertebrae, and parts of both front and hind legs were recovered. No other specimens of Animantarx have been found since. But this was enough to see that it was related to the giant nodosaur Peloroplites and fill in the pieces from there.
Animantarx would have lived alongside ornithopods like Eolambia (also discovered by the same couple, Carole and Ramal Jones, via radiography), Hippodraco, Iguanacolossus, Planicoxa, and Tenontosaurus, sauropods like Abydosaurus, Brontomerus, Cedarosaurus, and Moabosaurus, the basal therizinosaur Falcarius, the troodontid Geminiraptor, the tyrannosauroid Moros, the ornithomimosaur Nedcolbertia, the allosauroid Siats, the giant dromeaosaurid Utahraptor, and fellow ankylosaurs like Cedarpelta, Gastonia, and Peloroplites.
