Well-preserved dinosaur footprints have been excavated in the Hettangian of Corgnac-sur-l'Isle (Dordogne, France). They are attributed to a large thyreophoran dinosaur and clearly show a stegosaur-like 2-2-2 phalangeal formula for pes digits II, III and IV. Pes digit I is variably impressed. This is the first Early Jurassic thyreophoran trackway ever discovered, and the largest known ornithischian tracks of this period. It definitely shows that primitive thyreophorans were quadrupedal and suggests that phalangeal reduction preceded digital reduction in the evolution of advanced thyreophorans.