Short wings for massive flyers
Giant pterosaurs, and azhdarchids in particular, were without doubt the most magnificent flying animals that have ever lived, and to this day they keep amazing us with their absurd nature. Besides being flying animals as big as the tallest modern mammals, their wings were ridiculously short in comparation to their bulks. Whereas ornithocheiroids and other giant pterosaurs had those massive wings that utterly overshadowed the body as Walking With Dinosaurs made so famous, azhdarchids had proportionally much smaller wings, each wing slightly shorter than the animal’s height. The difference is as extreme as between the wings of a duck and those of an albatross – except that the “duck” is larger than the albatross by a large margin.
Part of the reason pterosaurs could get away with such disproportionate wings is perhaps due to the weight distribution being weird beyond belief. Quetzalcoatlus, despite being as big as a giraffe, probably weighted as much as much as an ostrich – 250 kilos, give or take. This is not because of hollow bones – as it turns out, pneumatic skeletons don’t affect body weight much – but because the animal’s torso was ridiculously small, beneath a meter in total length. As such, the part of the animal typically assumed to be the heaviest was probably around 10 kilos at most – way beneath the total mass of the largest modern flying birds.
Most of the remaining weight probably therefore came either from the head/neck or the limbs, and on the air this wouldn’t make the animal’s life any harder, as the four limbs formed the wing and the head/neck was already aerodynamically adapted, with the massive nasoanteornital frenestrae inflated and the beak and neck acting as a rudder on the air.
The wings themselves were probably quite wide themselves, as with most terrestrial flyers, but even with thin albatross wings Quetzalcoatlus would have been not only a good flyer, but a quite acrobatic one. Indeed, given how pterosaur wing membranes had muscle fibers and air sacs, it could probably have shifted between both shapes at ease.