Complex sentence: The ilium, the main hip bone, was supported only by two sacrals, a basal trait, but the pubis pointed backwards, a derived trait that parallels what is seen in dromaeosaurids and birds.
Split into simpler sentences: The ilium, the main hip bone, is supported by only two sacrals, a basal trait,. However, the pubis points backwards, a derived trait as seen in dromaeosaurids and birds.