 Its hindlimbs were very long and thin, and its forelimbs were proportionally longer than in relatives.The namesake fossil of the type species Amphicoelias altus, American Museum of Natural History 5764, is uncertain in included material.When described by Edward Drinker Cope shortly after its discovery in 1877, "Amphicoelias" was noted to include many back vertebrae, a single pubis, and a femur.