The Tyrannos, from left to right: Plesio, Styraco, Genghis Rex, Quackpot, Ankylo, Brachio and Terrible Dactyl.

The Tyrannos are the antagonists of the series. In contrast to the Dinosaucers, the Tyrannos have a total of seven members in their group on Earth. This number is somewhat rounded out by Princess Dei, who is apparently part of the Tyannos back on Reptilon, who was not part of the Earth expedition.

The main members of the Tyrannos are: