Dinosaur War Aizenborg (1977)

Dinosaurs reappear on Earth, stronger and more intelligent than before, led by Dinosaur Satan Gottes, and this time they are trying to rule Earth once more and wipe out mankind. Not only are they are alive, they are even thriving in an underground empire that they have built. In 1986, Ururu, the leader of the dinosaurs, declares war against humanity. In an attempt to reclaim Earth's surface, some of the dinosaurs evolve into deadly super monsters and start wreaking havoc on human population centers around the globe. The story revolves around the D-Force (D-Sentai), and its two members, a brother and sister team of Ai Tachibana and Zen Tachibana, the Special OPS force, whose mission is to combat the dinosaurs and protect humanity. But early on in the TV series, the siblings suffer a near-fatal injury from the massive explosion during the test of a prototype super-tank, the "predecessor to Izenborg". In order to keep them alive, they receive cybernetic body parts and other implants, which synchronize with their combat vehicle and form Aizenborg (Ai + Zen + Cy"Borg"; called Gemini in the U.S. film) to fight the dinosaur army. Halfway through the TV series their bodies are altered again, and the two are able to combine into a giant robot that can fight the dinosaurs in close combat.