Futabasaurus (フタバスズキリュウ Futabasuzukiryu) were prehistoric marine reptiles from the Cretaceous Japan in Tsuburaya's series, Dinosaur Squadron Koseidon.


Dinosaur Squadron Koseidon

The Futabasaurus, along with many other dinosaur and ancient reptiles, lived peacefully several million years ago, that is, until a race of aliens found that the fossil fuels of Earth where strongest when the dinosaurs lived. As such, constant attacks took place in Ancient Japan, with Aliens sending dinosaurs fleeing for their lives and some even to their deaths. The Futabasaurus usually stayed away from conflict and remained in the ocean, but where under attack when the Aliens sucked water from the sea, flinging the marine reptiles skyward.

In the series finale, the Futabasaurus, like most of the other dinosaurs and ancient life, where killed by a giant meteor, with Koseider cursing the fact he could not save the ancient animals.


  • The Futabasaurus props where two of the first original props made for the show. All others came from Dinosaur Great War Izenborg and Dinosaur Catcher.
  • While they look similar, the Futabasaurus are not reused props from Legend of Dinosaurs and Monster Birds, a Toei film.
  • While originally mistaken for Plesiosaurs, the official Tsuburaya Tokusatsu DVD Magazine and the show itself names them as Futabasaurus.
  • It uses a stock roar commonly used in the Tsuburaya Dinosaur Trilogy series.
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