Many animals (snakes, birds, frogs, basically anything that is not a mammal or marsupial) have no visible outer ear
So why do all Nichelings need auricles?
They don't.
I suggest an ear type that just isn't a visible ear. It would obviously have less hearing than normal ears but other benefits instead, like aqua/aerodynamic.
It could give +1 on swimming and flying because of less air/water resistance and maybe a little cold resitance, too, bacause a lot of heat goes away over the