User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-4672059-20120202160529/@comment-28303251-20120203172447

They probably just wanted the two games have their own exclusives and stand out, Portable 3rd would have Tigrex (and black), Bulldrome, Akantor, Ukanlos, and Amatsu. And Tri G would have Gobul, Ceadeus, Lagiacrus, Guran, and Braachi. (and the crap load of subspecies, lol). Oh right, Plessioth and the other Rath subs. lol