Saturn is the sixth planet from the star Sol (Sun) in the Solar System. Characterized by its broad, flat rings, the only known organisms known to have evolved independently in the Saturnian system were the Titanians—a prehistoric intelligent race that had become extinct many Earth years ago; and the Rheans—small, quadrupedal, tribal creatures that live below the surface of the moon Rhea.
Titan is the largest moon of the Saturnian System. It houses numerous ecosystems of organisms. Its most intelligent species, the Titanians, died out long ago, but some creatures managed to survive and their progenies still reproduce today.
Now, some organisms live on Titan that did not even independently evolve there. Intelligent organisms have colonized Titan and still live on the moon today. The intelligent organisms, which include Earthlings, Europans and Unknown Aliens have introduced the Titanian environment with many other organisms from other planets and moons.
Rhea is the second largest moon of Saturn. It houses many ecosystems just as Titan does, but much of the animals have not evolved there independently. Long ago, unknown aliens had brought creatures to the moon that were from somewhere else in the universe.