I WONDER - How Did The Quetzalcoatlus Eat?

Quetzalcoatlas, a large pterosaur, lacked bony crests and had elongated necks and toothless skulls. Its beak was adapted for spearing fish and small animals. Fossils were found in Texas, indicating it lived in a tropical coastal habitat 100 million years ago. Despite its size, it weighed only 550 lbs due to its hollow bones and streamlined frame.

What was the estimated weight of Quetzalcoatlas despite its size?

How did the physical structure of Quetzalcoatlas contribute to its flying ability?