Okay, this is just a wild guess that occured to me moments ago. The thing that the Space Jockey was laying on and the huge gun-like thing over its head could have been an early Yautja design for the sacrificial slab. It's probably not true, I'm not quite sure for myself, but the Derelict Ship might have actually have been of Yautja design. In the original script for Alien, it was a pyramid. That's where Paul Anderson based part of his idea for AvP on. Could Space Jockeys have been the Yautja's original form of Xenomorph host? And could the thing over the Jockey's head have produced an egg with its tittering contents? Any ideas?
~For centuries, human beings have worshipped these beasts as gods, beasts that will forever haunt us, beasts waging an eternal war.....~