Late Triassic of North America. Described in 1875. It was a type of aetosaur: a line of pseudosuchians that was herbivorous, as indicated by their small, leaf-shaped teeth and extensive bony armour (osteoderms). Unlike most aetosaurs, Typothorax did not have have large shoulder spikes, but instead had spikes off its neck.
Aetosaurs are an unusual radiation of pseudosuchians that have interesting features that evolved convergently in later (Jurassic) armoured, herbivorous ornithischian dinosaurs.