To me everything is perfectly clear in Genesis:
24 And God said, Let the earth bring forth the living creature after his kind, cattle, and creeping thing, and beast of the earth after his kind: and it was so.
25 And God made the beast of the earth after his kind, and cattle after their kind, and every thing that creepeth upon the earth after his kind: and God saw that it was good.
26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
27 So God created man in his own image, in the image of God created he him; male and female created he them.
This is why I think any other "human ancestors" that people talk about fall into every other creeping thing. I'm not saying these other creatures aren't important because God had a purpose in creating them. I just think they were beneath man because God specifically created man. I'm totally open to corrections if I've missed something.