

As you can see in this drawing of Aegon the Conqueror riding Balerion the Black Dread, as depicted by Jordi Gonzalez Escamilla, these creatures have two wings and two back legs: Martin's A Song of Ice and Fire world stems back to the concept art used in the Game of Thrones encyclopedia A World of Ice and Fire.

This visual depiction of dragons in George R.R. Nerdist's Sarah Keartes ran an article/PSA back in 2016 explaining how Daenerys' children are, technically speaking, also wyvern. This semantics debate about which creatures are or aren't dragons isn't a new one, especially around Game of Thrones.
