User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-93.96.173.97-20111128170513/@comment-111.240.225.162-20111128173247

Or to be exact, those are monsters that existed in previous games, but haven't been confirmed in 3G yet. The ones that already appeared in MH3 and P3 would stand a good chance of coming back, but it's totaly up to Capcom to decide which non 3rd Generation monsters can make the comeback.