Dinosaur

Dinosaurs were a diverse group of prehistoric reptlies that once roamed Earth during the Mesozoic Era.

Biology
Dinosaurs were characterized in numerous shapes, sizes and forms; sauropods (massive quadrupedal long-necked herbivorous dinosaurs), theropods (bipedal carnivorous dinosaurs), ceratopsids (quadrupedal horned frilled herbivorous dinosaurs), ornithopods (bipedal herbivorous dinosaurs), etc.

In popular culture
Extraterrestrial life forms similar to and/or identified as dinosaurs include the following.
 * In the Carnivores universe, there are various aliens that resemble earth fauna, mostly dinosaurs.
 * In the Ben 10 universe, The Vaxasaurians resemble humanoid sauropods, the Pturbosaurians resembled humanoid pterosaurs and the Kaosseffexx Ultimasaurias resembles tyrannosaurus centipede hybrids. It's unknown if the Pturbosaurians shared the same planet as the Vaxasaurians in the reboot. The Kinecelerans resembled humanoid velociraptors.
 * The Triceratons from Teenage Mutant Ninja Turtles, are extraterrestial humanoid bipedal-triceratopses. In the 2012 TV series, they were enemies of The Kraang.
 * Hanakans, Rageshkors, Renkrodas and Nyssholoras from the Starfinder universe.
 * In the Saurians from the Star Fox universe, are anthropomorphic prehistoric creatures.
 * The Babarians from Dragon Ball, are dinosaur-like humanoids.
 * In the Troop universe, the Basilisk is a raptor-like creature and Borlak is a outdated dinosaur-like beast.
 * The Mobosaurs from Archie's Sonic The Hedgehog universe, are the mobian versions of Earth's dinosaurs.
 * The Panderavis is a species evolved from the extinct therizinosaurs.
 * In the Italian Donald Duck comic Zio Paperone e l'oro del papersauro, first published on December 30, 1990, the Dinosaurs are humanoids who were dominating planet Earth with advanced technology, but an ice age caused them to leave Earth behind and begin a new life on another planet.