"Well in the trailer you could see a rathalos and an unknown sea monster ."
i thought it was a rathian. and wikipedia said that the sea monster was announced "Gilkura, has recently been announced however. It is the creature you see at the end of the trailer. It is a giant bird like fatalis that lives underwater. There will be a whole new fighting system to aid in the battle of this legendary creature."
it doesn't say very much and i don't know of an 'official' MH3 site so i don't know where to look for another source. --- and yet i fit in so well. Brawl FC: 2191-7315-2783