Examples of cultural diffusion is present at most ancient sites. How old is it?...and how did it happened?
Was it brought by the Europeans? …or by a much older Sea-Faring People?
Weather that phenomenon is accepted by recent or older schools of thought, it is still present in the tribal folklore of the Americas.
“The North-American Indians relate that they were conducted from Northern Asia by a man-fish. “Once upon a time, in the season of opening buds, the people of our nation were much terrified at seeing a strange creature, much resembling a man, riding upon the waves. He had upon his head long green hair, much resembling the coarse weeds which the mighty storms scatter along the margin of the strand. Upon his face, which was shaped like that of a porpoise, he had a beard of the same color. But if our people were frightened at seeing a man who could live in the water like a fish or a duck, how much more were they frightened when they saw that from his breast down he was actually a fish, or rather two fishes, for each of his legs was a whole and distinct fish. And there he would sit for hours singing to the wondering ears of the Indians the beautiful things he saw in the depths of the ocean, always closing his strange stories with these words:—‘Follow me, and see what I will show you.’ For a great many suns, they dared not venture upon the water; but when they grew hungry, they at last put to sea, and following the man-fish, who kept close to the boat, reached the American coast.”
“It is not impossible that the North-American Indians may have symbolized the sun in the same manner as the Syrians, and that this legend may signify that the early colonists, to reach the New Land, followed the fish-course of the sun, which as man goes from East to West, whereas when it dives it swims from West to East, the course taken by the Indians in their canoes. The wanderers in the Canadian forests have also their fish-woman, of whom a tale is related which bears a lively resemblance to that of Undine, and which is not a little like that of Melusina.”
Here’s a long, but nice read….
https://en.wikisource.org/wiki/Curious_Myths_of_the_Middle_Ages/Melusina