Regarding

> > According to a tradition from the Lower Sepik in New Guinea, a
> > man called Nu went up a hill, killed his son, tore the body in
> > pieces, and threw each in a different direction, each time saying
> > something in a different language. The pieces of the boy's body
> > became the ancestors of villages in different parts of the
> > country. [Knappert, J. (1992), "Pacific Mythology", Aquarian
> > Press: 165.] (So there's a Nu who's an ancestor, at least, even
> > if not a flood hero).

I wouldn't read much into this myth. The Lower Sepik is an area of
particularly rich linguistic diversity and an explanation of this
situation would have been needed by local people. It is unlikely to
have any connections outside the country, except perhaps to
Austronesian related peoples who traded along the coast east from
Vanimo.

Regards

John