Pteroz are flying Dinoz who soar above Big All-Hot. They have an impressive sense of territory and it's sensible to not disturb a Pteroz Mother protecting her eggs. They are quite hard to tame but really good fighters.
Needs to be unlocked by defeating the Strange Dinoz (requires Dinoz level 9) before you can buy it. Minding Flight Skill, the Pteroz could be a great fighter.
The Pteroz has the potential to unlock 2 of the Unique Skills (those that apply to all your Dinoz). To do this you have to plan the progression of air skills, as you cannot afford to get them all. Focus on the paths begun by Mistral and Agility.