Dinosaur

The Dinosaurs are prehistoric animals from Earth and Magix who appear in the comic series and in the show in Season 7.

Roxy the Seventh Fairy
In Roxy the Seventh Fairy, the Trix sneak into the Fortress of Light with the help of Yerka and find the skeleton of a dinosaur similar to a T-rex that they resurrect using a spell. However the spell was incomplete and parts of the dinosaur were only partially restored, and it broke free from the museum, roaring around the fortress because it was suffering.

The noise woke up the Winx and the Council of the Fortress of Light. Just as the Winx were about to transform to fight the dinosaur, Roxy stopped them and told them that the dinosaur was angry because it was suffering. Roxy transformed and healed the dinosaur, who became as calm as a puppy. The dinosaur then went to help people on a farm.

The Flute of the Shaman
After Arzach uses his flute to transform the vehicles in Gardenia into prehistoric mammals, Stella wonders what kind of animals are those, and Tecna replies that they are prehistoric animals who populated the Earth after dinosaurs became extinct.

Trivia

 * Dinosaurs were a group of animals who were the dominant forms of terrestrial life on Earth in the prehistoric period known as the Mesozoic Era
 * The dinosaurs who appeared in Roxy the Seventh Fairy and A Friend from the Past were both modeled on the Tyrannosaurus rex. They are bipedal meat-eating dinosaurs with small arms with only two fingers similarly to how the Tyrannosaurus was.
 * However the dinosaur from the Fortress of Light had smooth green scaly skin while the dinosaur from Prehistoric Magix had red skin with a green crest made of big, rock-like scales. Therefore it is possible that they were not members of the same species.