User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-1780011-20130921142323/@comment-17735225-20130921154004

Amphibian's hindlegs are a bit longer and bigger (in proportion to body) structure-wise, also supposely a mphibians are technically not wyvern at all  so akantor cannot be an amphibian. Another thing to note is that there's a very thin membrane on the forelegs of akantor, indicating the degraded wings of flying wyvern ("pseudowyvern as many people called it"). So definitely Akantor is flying wyvern, physiology-wise.

Yet he can be considered an elder dragon though, due to the disaster he can cause.