Complex sentence: The occipital region of "Stegoceras" was well-demarcated for muscle-attachment and is believed that the jaw movement of "Stegoceras" and other pachycephalosaurs was mostly limited to up-and-down motions with only a slight capability for jaw rotation.
Split into simpler sentences: The occipital region of "Stegoceras" was well-demarcated for muscle-attachment. It is believed that the jaw movement of "Stegoceras" and other pachycephalosaurs was mostly limited to up-and-down motions with only a slight capability for jaw rotation.