Spartakus and the Sun Beneath the Sea (1985)

Long ago, the mystical civilization of Arkadia was one of the most advanced places on Earth, until the end of the world came and forced the land and it's people underground. After that great cataclysm, the Arkadians lived deep in the center of the Earth and created an artificial sun called the Shagma (Tera in the USA version), according to forgot their past on the surface in an attempt to erase their mistakes to start again. But one fateful day, so much years later, the Shagma began to fade out. In a desperate act, the children of this unusual civilization and their ship with a mind of it's own broke into to the secret museum, which was considered forbidden except for the creatures who are in charge of it, and reactivate the long-time ago deactivated museum's computers. Looking for save Shagma and Arkadia, they create a woman named Arkana who have feet, despite Arkadians, in order for traveling to outer world in a turtle-shaped ship with IA and named Shag-Shag (Tehrig in USA version). Helped by two descendants of pangolins and Arkadians' pets, Bic and Bac, Arkana and Shag-Shag meet Spartakus, a voyager of the stratus beneath the earth and gladiator from the Barkad's desert, who has a bracelet linked with the Arkadians' past. After they meet two brothers of the surface named Rebecca and Bob (Matt in the USA version), the group starts a travel exploring strange worlds and struggling with menaces as Sea Pirates who live between the stratus, in an odyssey full of adventure to save Arkadia before Shagma fades out forever.