OK, I think this site is getting a generous assortment of tags which have hardly anything to do with world building. Ahem anyhow.
So. The first major difference immediately noticeable between a pteranodon and say, a quetzelcoatlus or arambourgiania is the head crest. Neither of the two giants has a prominent head crest! Now it would be out of scope of this site's discussion to start arguing why/how the azhdarchids lost the head crests which is the most prominent feature of many Pterodactyloidea genera, but it is safe to assume that if pteranodon was fully terrestrial like the azhs, it would probably also have lost it's head crest.
The next difference (if you look carefully at their shoulder and hand morphology) is their standing posture. The azhdarchids have a shoulder morphology more suited for long term standing on the ground. These monsters spent a large portion of their times on carcasses and were not as active fliers as pteranodons. Azhs stood with their elbow joints somewhat splayed out which resulted in spreading their weight outwards and not directly on their elbows. Pteranodons standing posture was more compact.
Also, while both these types of pterodactyloids had truly long jaws (beaks?) azhdarchid beaks were more sturdy and thicker than those of pteranodon. That is probably due to the fact that while pteranodon only had to grip fish and gulp it down, the bigger babies had to deal with dinosaur flesh which is much harder to pull apart than fish flesh. You could say that while a pteranodon's jaws were for catching and holding fish, azhs' jaws were suitable for poking and hitting down on flesh (like a woodpecker's beak, only 100 times bigger).
Plus, some scientists have postulated that the azhs had lost their ability to fly. Although there is no consensus on the matter but the theory exists with many believers in the scientific community.
And, do not take azhdarchid's lifestyle as hunters for granted. A lot of researchers think they were rather scavengers than hunters. How exactly do you bring down ... say ... an ankylosaurus or iguanodon with a body shape that of a giant pterosaur? And even if you did, would the raptors or a roaming T-Rex really let you eat your kill undisturbed?