Not every dinosaur grew up to be a mighty predator like Tyrannosaurus rex or a hulking vegan like Apatosaurus. A few stayed small, and some of the smallest dinosaurs that ever lived — tiny enough to nip at your heels — were among the first to spread across the planet more than 200 million years ago.

Fossils of these miniature, fanged plant-eaters known as heterodontosaurs, or “different toothed reptiles,” have turned up as far apart as England and China. Now, in a discovery that has been at least 50 years in the making, a new and especially bizarre species of these dwarf herbivores has been identified in a slab of red rock that was collected in the early 1960s by scientists working in South Africa.