New 'Villain' Dino for JP4?

For the sake of this discussion, I'm considering the primary 'vaillain(s)' or antagonist(s) of the film to be the dinosaur(s) that is actively pursuing the heroes for the majority of the film. Despite the T-Rex making a huge splash in Jurassic Park, we all know that the real antagonists of the film were the Raptors. In The Lost World, the raptors took a bit of a backseat to the dual rexes. In Jurassic Park III, we saw the rise of the Spinosaurus. My question then is, do we continue this tradition of shuffling the primary 'villain' or antagonist of the movies with Jurassic Park IV? We know there will be some new dinosaurs, but if the emphasis isn't on the Rex, Raptors, or Spino, who can take center stage? Will it be a new dino or a familiar face? Personally, what I would like to see, is a return to a familiar dinosaur - but seen in a new light. In the Jurassic Park novels, the Dilophosaurus is in-between the size of the Raptors and the Rex and is a small pack hunter (a pair in the book). What we see in the movie is downsized to put more emphasis on the Raptors - but this could easily be explained for a new film as simply being a juvenile (making the 'adults' proper-sized). [img]http://fc02.deviantart.net/fs71/i/2011/098/6/c/dilophosaurus_by_kyoht-d3diw65.jpg[/img] Alternatively, a really interesting idea proposed in The Lost World (book) is that Carnotaurus had the ability to change its skin colour and blend with its environment. I actually found this one of the scariest portions of the book, because the idea of a dinosaur that is virtually invisible at night is terrifying (plus they also seemed to hunt in pairs) - and I think this could make a great addition to the films. [img]http://0.tqn.com/d/dinosaurs/1/0/-/Q/-/-/carnotaurus-sastrei.jpg[/img] Lastly, another medium-sized pack-hunting dinosaur I think could work (though it's relatively boring, compared to the other two) is Allosaurus - a fairly well-known, common dinosaur that could work (though it wouldn't offer much contrast to the Rex, except being smaller/faster/pack-hunter). [img]http://0.tqn.com/d/dinosaurs/1/0/g/C/-/-/allosaurusSP.jpg[/img] What are your thoughts, everyone?