What distinguishes pterosaurs from dinosaurs?

Pterosaurs were a group of prehistoric flying reptiles that lived during the Mesozoic Era, alongside dinosaurs. While they share some similarities with dinosaurs, there are several key differences that distinguish pterosaurs from dinosaurs.

1. Flight:
The most significant distinction between pterosaurs and dinosaurs is their ability to fly. Pterosaurs were the first vertebrates to evolve powered flight, and they had wings made of a leathery membrane of skin called the patagium. This unique adaptation allowed them to soar through the skies, while dinosaurs remained grounded.

2. Body Structure:
Pterosaurs had a distinct body structure that was adapted for flight. Their bones were hollow and lightweight, similar to modern birds, to reduce the overall weight of the animal. Additionally, pterosaurs had elongated fourth fingers that supported the wing membrane, while dinosaurs had more robust limbs designed for walking on land.

3. Size and Diversity:
Pterosaurs exhibited a wide range of sizes, from small species with wingspans as little as a few inches to the largest, like Quetzalcoatlus, with wingspans exceeding 30 feet. Dinosaurs, on the other hand, were primarily terrestrial and ranged in size from small, chicken-sized species to enormous dinosaurs like Argentinosaurus.

4. Extinction:
While both pterosaurs and dinosaurs went extinct around 65 million years ago during the Cretaceous-Tertiary extinction event, pterosaurs were not direct ancestors of any living organisms. They were a distinct group of reptiles that evolved alongside dinosaurs but did not give rise to any modern-day animals. Dinosaurs, on the other hand, evolved into birds, which are their closest living relatives.

In conclusion, the primary distinction between pterosaurs and dinosaurs lies in their ability to fly and their unique body structure. Pterosaurs were the first vertebrates to develop powered flight, had lightweight bones, elongated fingers to support their wing membranes, and exhibited a wide range of sizes. While both pterosaurs and dinosaurs went extinct, pterosaurs were a distinct group and did not give rise to any living organisms, while dinosaurs evolved into birds.