 Instead, "Amphicoelias" had vertebrae, where both ends are mildly to moderately concave.Because of this difference, Cope named two separate families to contain the different morphs of vertebral centra, one being Camarasauridae and the other being Amphicoeliidae.As well, "Camarasaurus" possessed (openings in the side of the centrum) that were taller than long-contrasting to the condition in "Amphicoelias"- and a more robust pubis and femur.