Why Is a Pterosaur Not a Dinosaur?

Because they flew and their front limbs stretch out to the sides, they are not dinosaurs. Instead, they're a distant dinosaur cousin. Pterosaurs lived from the late Triassic Period to the end of the Cretaceous Period, when they went extinct along with dinosaurs. ... Like birds, pterosaurs had lightweight, hollow bones.

Is a pterosaur a dinosaur?

Neither birds nor bats, pterosaurs were reptiles, close cousins of dinosaurs who evolved on a separate branch of the reptile family tree. They were also the first animals after insects to evolve powered flight—not just leaping or gliding, but flapping their wings to generate lift and travel through the air.

What was not a dinosaur?

Marine reptiles, such as ichthyosaurs, plesiosaurs and mosasaurs are not dinosaurs. Nor is Dimetrodon or other reptiles in the same group (previously called 'mammal-like reptiles' and now called synapsids). None of these other extinct groups shared the characteristic upright stance of dinosaurs.