There is great deal of controversy in the question of who actually fathered Pelius and Neleus. One account illustrates Poseidon as the father. The story is described:
Unbeknownst to anyone, Tyro- the daughter of Alcidice and Salmoneus, abandoned her two twins Pelias and Neleus after they were born. Their alleged father, Poseidon, lay with her after having disguised himself as the river where Tyro would chant her love for a river god whose name was Enipeus. Supposedly, a horsetrainer found them, and saved their lives. Eventually, they found their stepmother Sidero and killed her on holy ground.