On the one hand, there are folks who think fossilized dinosaurs constitute evidence for evolution. On the other hand, there are folks who think aliens have been to planet earth.
The obvious solution is staring us in the face: dinosaurs are aliens!
After all, we’ve all seen reptilian aliens in movies. So this clearly represents a Jungian racial memory of cave men encountering hostile saurian alien species. What could be simpler? That's Exopaleontology 101, dude!