User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-26074976-20130703191328/@comment-8874090-20130704084641

Leviathans and piscines aren't that similar at all:

-piscines stand only on their back legs, while leviathans mostly walk on all four

-leviathans have four legs, piscines' front legs are developed into fins

So, I don't think it would be a problem that they would be too similar.