Late Triassic (203-196Ma) of southwestern USA. Discovered in late 19th century and described in 1887 by Edward Drinker Cope (of the Bone Wars fame).
Long-legged, lightly built, ~2m long, bipedal carnivores. Over 1000 specimens of Coelophysis exist, including many complete skeletons; most found at Ghost Ranch quarry in Arizona. Some specimens preserve gut contents, showing the remains of small early crocodiles that were their last meal.
Coelophysis was very similar in form to the earliest theropod dinosaurs.