Xenomorph/Alien in Trailer: Speculation

I'm surprised to see little mention/discussion surrounding the rather startling cameo, in the new trailer, by what appears to be an elegantly re-designed (yet clearly Identifiable), classic xenomorph figure, embedded into the wall (of the pyramid/spacecraft?). I've read some passing comment that refer to it as a stone carving, but how can we be so sure? Might this alien be in fact the larger, more fearsome creature that Mr. Scott describes as the product of a space jockey-born version of the human-xenomorph offspring? Although it does resemble the surrounding structure, I've speculated that perhaps it is merely resting (developing?) in its own secreted, cocoon-like resin, ready to pounce down and attack the "Prometheus" crew. But even if it is a mere carving, what are the implications of finding this xenomorph depiction? It see to me this has to be, at minimum, one of if not THE most important spoilers shown thus far, and the closest direct link (aside from the space jockey/spacecraft design) to the original "Alien" film and franchise. Part of me doesn't believe Ridley would divulge THAT much spoiler, so the true design of the actual, giant spacejockey-alien still remains to be seen. On that line of reasoning, the "trailer xenomorph" could represent an earlier, ancient alien, perhaps associated with the engineers' role in earth/human history; maybe an alternate version of this genetic bio-weapon they attempted to use on earth; a prototype alien they developed to take back to earth to aid their re-conquest/destruction of humanity (hence the Prometheus crew's imperative to stop them at all cost); or it may be the very thing that ended the engineers' reign on earth: an experiment gone wrong. Whatever it is: a stone mural, a real living xenomorph camoflaged in its den, something ancient or new, space jockey or human hybrid, or an artistic rendering (message, warning, historical account, other) depicting what the engineers have developed/are developing, etc., it's still an Amazingly Cool, Mysterious sight to behold! What are your thoughts on this? Feedback on any of these seculations, or your own theories, are much appreciated. Thanks!