ok so here is the official def. of Progenitor

I'm pretty sure Ridley Scott has said that the Xeno in this film will be a predecessor of the Alien creature from 79'. It could turn out to be a better design than the creature from the original movie. I could even see them using some of Gigers' other painting for inspiration.

well it means a descendant or thee originator of the species

descendant means your offspring and so on down the line after you....you mean anscestor, precurser or originator @20thcenturybuick...........

It does look like a frog, but it may by a "splurt" of liquid as well...perhaps Holloway is out-of-frame here, and: -Noomi and Kate examine Engineer head/helmet -Holloway takes some type of genetic booby-trap to the face -Holloway's DNA re-written, becomes Engineer...? We go in search of gods, and only to become the gods...could be commentary from Riddles on "finding God within ourselves", or something...or not. :P

If this film does indeed preceed Alien and the Xenomorph in that movie alone, I'd have thought the creature(s) we see in Prometheus will be highly intelligent. Especially if they somehow share the same DNA/Genetic makeup as the SJ's, which appears likely. . .

i think you may be right Robotpo, iv always stuck to what i said in old post that the blue guy in the space jockey room looks like Holloway. It kina backs up what you say

the question is will we see an earlier xenomorph simply because this flm takes place before alien...or will we see thee first origional xenomorph