Fruitadens is the smallest known ornithischian dinosaur , with young adults estimated at 65 to 75 cm ( 26 to 30 in ) in length and 0.5 to 0.75 kg ( 1.1 to 1.7 lb ) in weight . Fruitadens it is interpreted as an omnivore . Fruitadens is the smallest known ornithischian dinosaur , with young adults estimated at 65 t in length and 0.5 t in weight .