Have you seen the mural screen cap yet? It makes me super excited, I can't wait to rent the movie, so I can pause it and see it for myself. I do believe the alien at the end is a juvenile queen, and might be seen in sequels, because the center of the wall carvings looks just like it, with a mature queen over it. And then in the two bottom areas you see facehuggers wrapped around what I can only assume are humans.
I honestly don’t think Ridley or Lindelof intended it to be a queen; the queen was an addition to the mythos after “Alien”, and so I’m not expecting Ridley to support it.
My take is that it is a xenomorph-like creature, but clearly a different strain than the one we see in “Alien”.