User blog comment:Kogath/Monster Hunter X Discussion/@comment-25706585-20151005104307/@comment-25275196-20151006215436

Well, Regular and Ivory have both learned land based combat, so it could happen with abyssal. I just hope that we don't fight him in a half submerged cave and he spends half the time swimming around like plesioth used to do. But still, subspecies haven't even been confirmed yet, even though it's unlikely that either will return, it's still more likely for ceadeus.

Plus, Ceadeus does occasionally come to the surface, we knew that from the beginning, From both the intro video, and also the CG cutscene after repelling it.