I was just gonna go with essentially smart utah raptors gone evolution and having been genetically engineered so that they would eventually be smart, where they then started expanding from their jungly jurassic world to space because of the tech inside genetic labs on the ground from unknown peoples. And the fact that the entire planet they live on is literally a massive experiment gone wrong- the original owners left, leaving behind a gold mine in the genetic laboratory databases, booting what would be millenia-long tribal raptor peoples into modern+++ era, where they eventually found out that their planet is about six times younger than all the planets around them, and the sun, and everything, and that the core of the planet was actually three miniature black holes, kept stable and used for energy by massively complex indecipherable machines in the heart of the superplanet. 

Simply speaking, an artifically created planet that used the gravity from controlled miniature black holes to both create the planet- just let the gravity break through but not anything else, and let the dirt and crap collect and then terraform after you've blown up and collected all the nearby planetoids and asteroids, and then do whatever to the surface. 

Three miniature blacholes, orbiting each other in the center of a massive planet, controlled tightly by a super-advanced AI that continually refuses to admit my peoples, who are fine with that beacuse they couldn't hope to match it, nor could they do anything to it without risking their entire nation in the process. ;DD

I got the idea off a Christopher G. Nutall book.