The many names of the sea-dog

While researching heraldry and monsters, I was surprised to learn that creatures like the alphyn, enfield, and sea-dog (or water-dog) were actually variations on the same thing.

The onchú (literally "water-dog," probably from on "water" + cú "hound") appears to be either an otter or a mythologized version thereof. Through assimilation with the heraldic sea-dog and phonetic mutation into the alphyn and enfield, it acquired features like a fishy mane and avian talons.

• The sea-dog is a canine beast with fishy features including scales and fins.
• The alphyn is a vaguely lupine beast with avian talons and a long knotted tail.
• The enfield is a vulpine beast with avian talons.

Research links:

• https://abookofcreatures.com/2017/04/03/onchu/
• http://mistholme.com/dictionary/alphyn/
• http://mistholme.com/dictionary/enfield/
• http://mistholme.com/dictionary/sea-monsters/
• https://www.sacred-texts.com/lcr/fsca/fsca73.htm
• https://www.sarahsawyer.com/2012/03/mythic-creature-the-alphyn/