User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-24296662-20140501151436/@comment-184612-20140501192546

@Cottonmouth255:

That's due to them being in different lands. MH4U covers a few areas of the Old World so it makes sense to bring back more old monsters. If anything, every monster from the Old Desert and even Desert could return just due to Old Desert (MH4U) being an old location (the deserts were next to each other).