List of fictional extraterrestrial species and races: RNameSourceTypeRaasMaster of Orion IIIRabotevsHarry Turtledove's Worldwar book seriesA subject species of the Race in the Worldwar book seriesThe RaceMoreau seriesAmoeboidThe RaceHarry Turtledove's Worldwar book seriesReptilian, often called "Lizards" by humans due to their appearance.RachniMass EffectInsectoid species driven to the brink of extinction by the Krogan.RadiclesOK K.O.! Let's Be HeroesRaielPeter F. Hamilton's Pandora's StarRako-GordaUtopiaRaloiMass EffectAvian species forced to withdraw from the Milky Way due to the arrival of the Reapers.Ram PythonsBattlelords of the 23rd CenturyRancorsStar WarsRaptorsNexus: The Jupiter IncidentRaxacoricofallapatoriansDoctor WhoReapersDoctor WhoReapersMass EffectLarge robotic species modeled after cuttlefish. Operate on cyclical, genocidal programming.ReapersX-COM: UFO DefenseRegulC. J. Cherryh's Alliance-Union universeRelgariansFarscapeHumanoidRemansStar TrekHumanoidRe'olStargate SG-1HumanoidReplicatorsStargate SG-1Artificial lifeform. Two variants are known to exist, in a small mechanical insect shape as well as full humanoid.Re'tuStargate SG-1RigelliansLensman booksBarrel-shaped with four tentacular arms and four stubby legsRigellians The SimpsonsRiimThe Voyage of the Space Beagle by A. E. van VogtRillsDoctor WhoRimerunnerExpeditionRimmerRed DwarfHologram-humanoidRisiansStar TrekRisians are extremely open and will freely share their planet, and even themselves, with vacationers – a practice known as "Jamaharon".Robotech MastersRobotechRodiansStar WarsRoger the AlienAmerican Dad!Rogue SimulantsRed DwarfHumanoidRomulansStar TrekHumanoidRullThe War against the Rull by A. E. van VogtRutansDoctor WhoRyouko AsakuraThe Melancholy of Haruhi SuzumiyaHumanoid interfaceRyqrilTimothy Zahn's The Blackcollar