I've heard the word 'progenitor' used. From Merriam-Webster:
A person from whom one is descended: ancestor, antecedent, ascendant, father, forebear, forefather, foremother, mother, parent, predecessor. One that precedes, as in time: ancestor, antecedent, forerunner,...
A direct ancestor. An originator of a line of descent; a precursor. An originator; a founder: progenitors of the new music.