If there is no readme, it isn't royloo's.

I asked because it was textured and had a full set of teeth, qualities that it shares with royloo's prop. It was certainly too detailed to come off one of Poser's skeletons. :)

I've run across many 3ds skulls without documentation, so I doubt that I could easily identify it for you. Two places you might check are Reebo's Meshyard and 3D Cafe.