The Pterodactyl is a "living, breathing Kairu relic" according to Maya, since it was a fossil but was brought back to life by Professor Knox.
This creature was actually a fossil embedded in a chasm where Professor Knox discovered. But when he touched it, the Kairu nearby regenerated its body and mind.
It mades its first "live" appearance in The Kairu That Time Forgot. It, at first, captured Mookee and gave Team Stax and Battacor a merry chase but escaped. Later, it was almost caught by Professor Knox but thanks to Mookee, they thrawted him. Later, Team Stax obtained just enough Kairu for a new X-Drive but just enough to keep the legendary creature alive.