You could extract the faces then group them, and then just move the pivot point to the middle of the grouped faces. Uhm, really I don't know why you would want it in a bunch of peices. If it was nurbs you could just add isoparms and use the cut curve tool to detach it. You could always go polys>subdiv>nurbs, make your cuts>polys, group patches of polys. Never accually tried to do such I thing I guess. Another way would be to duplicate the dino, go into faces selection mode, cut the edge of the arm or leg or whatever, then delete all the faces you don't need. Repeat for each part.