>>4063263 (OP)There is no exact line, biology is the science of exceptions, if you draw an objective line all you're doing is drawing lines on the sand, ergo, it's abstract, that being said, it doesn't mean there isn't a line, it's just difficult to narrow it down fully, the difference between an Abbo and a nordid is clear as day but it may be harder to tell apart the nordid from like Alpinid or smth, in other words it's just a pointless task.