You're really good at drawing, but that picture makes me a little uneasy. It looks like Duckys mom is sorta forcing Pteronto into an act and he doesn't like it too much. Were you looking at Petries uncle when you drew him or something? I swear to god it looks like a traced picture of Pteronto. Perhaps giving him more of the Petrie look might help.
I'm not trying to diss your work or anything. I certainly couldn't do it, but focusing more on the facial features might make it look more like the children actually grown up instead of exactly like the adult characters. Please understand that this is supposed to be constructive criticism, not just mindless and/or mean comments. I'm sorry if I offended you in any way. I can't wait to see your other work though.
You've got a real talent.
First of all, it's spelled Pterano.
I didn't trace trace anything as you imply.
I used Pterano's basic layout for adult Petrie. They are the same species. I honestly can understand how you'd think it looks similar to Pterano, yet maybe not as close as you think. It takes experiance to recognize such things. ;3
Yikes! I looks like Ducky's mom is on Pterano? Wouldn't that be kinky? XD
Yet, I had to make an adult Ducky. I think it's a pretty good assumption to believe she'll look very much like her mother. ;3
Facial features of the children? Maybe you could create a tutorial for me so I can see what you mean. I think I did a fantastic job. ^^
Well, as far as your constructive criticism goes, I need helpful tips not blunt opinions on what you think I did. I need a direction, but it's a good attempt.

I'm not offended in the least bit either. ^^ After all, I do visit DeviantArt. @.@ Those people on there are crazy.
No, no, my dear. I apologize if I offended you with my art seeing as it made you "uneasy." ;3 I'll try to dish out a better warning next time.