Many depictions of merfolk show the ears as a set of ray-bearing fins, resembling the pectoral fins of fish
However, this doesn't make much sense from an anatomical perspective; the pectoral fin is not homologous to the ear, nor part of the head. It is instead a limb, complete with multiple sections and a shoulder
Could this particular member, in terms of its anatomy and development, realistically take form?
The head would be fully humanoid apart from the fins, which would be mobile and like the pectoral fins of a fish in their structure