It'd be interesting if Pterano ended up being Petrie's dad. I've always felt Pterano looked a little like Petrie (but then again, some of Petrie's siblings look pretty similar to him too).
Petrie certainly has the opposite personality of Pterano. Pterano is dogmatic, adventurous, prideful, and risks going into Mysterious Beyond for The Stone of Cold Fire. Petrie is uncertain, timid, is not a risk taker by nature, and would prefer to avoid the Mysterious Beyond. There is precedence for parents and children to be opposites, so Pterano coukd be Petrie’s father.
Or maybe a character arc for Petrie would be for him to slowly become like Pterano as he gains more self-confidence, so it's now a matter of him trying to find a balance.
This is based on my observations of my own life in regards to my father.
Intriguing anaylsis Dr. Rex. This would give as you said Petrie room to evolve and change. Petrie is in need of some character development. Spike speaks, Cera has learned to temper her temper and get along with siblings, Little Foot has built a bond with his Father Bron and navigated the emotions of having to wait for his herd to pay the Great Valley a visit. Ducky has remained like Petrie rather the same; they both need an arc.
