Over eight decades ago, while pondering the heavily-armored dinosaur Scolosaurus, the eccentric paleontologist Franz Nopcsa proposed what is probably one of the oddest ideas in the annals of paleobiological speculation. Scolosaurus was a low-slung quadruped that shuffled around what were then thought to be parched sand dunes. Even though its close ankylosaurian relatives had been interpreted as herbivores from the very start, the Cretaceous desert may have been nearly devoid of low-lying vegetation. But there was another source of food. Perhaps Scolosaurus was an insectivore, Nopcsa suggested, nabbing little arthropods as if the dinosaur were an overgrown horned toad.

Nopcsa’s proposal didn’t catch on. The little leaf-shaped teeth in ankylosaurian mouths accorded better with an herbivorous diet,