What is the difference between a pterosaur and a dinosaur?

Many people think that pterosaurs were dinosaurs, but this is not correct. Pterosaurs were flying reptiles that lived at the same time as dinosaurs.  Although both pterosaurs and dinosaurs are reptiles, and they belong to a larger group called the Archosauria, pterosaurs evolved separately and are classified as a distinct order from the Dinosauria.

Cladogram of the Archosauria explaining the difference between a pterosaur and a dinosaur. Cladogram based on Nesbitt (2011). Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur from Nesbitt (2011)

As the fossil record of basal archosaurs is fragmentary, the composition of the Archosauria remains controversial.  For example, some phylogenetic assessments place the Phytosauria outside the Archosauria.

What is a Pterosaur?

Pterosaurs were reptiles that evolved powered flight during the Mesozoic Era. They appeared more than 220 million years ago and became the first vertebrates to achieve true flight. Although they are often erroneously referred to as “flying dinosaurs”, pterosaurs were not members of the Dinosauria clade.

Famous pterosaurs include:

• Pteranodon
• Rhamphorhynchus
• Dimorphodon
• Quetzalcoatlus
• Tapejara

A model of Tapejara imperator (Safari Ltd)

The picture (above) shows a model of a Tapejara pterosaur.  It is from the Wild Safari Prehistoric World series of prehistoric animal figures.

To view the range of Wild Safari Prehistoric World animals in stock: Museum-quality Prehistoric Animal Figures.

The wings of pterosaurs were formed out of skin that stretched from the body over the forelimbs and along an elongated fourth finger.

Unlike birds, pterosaurs did not have feathers on their wings. The wing membrane was strengthened by tiny fibres called actinofibrils, which helped provide support and flexibility during flight. Pterosaurs had lightweight hollow bones and powerful chest muscles, adaptations that made them highly efficient flyers. Some species, such as Quetzalcoatlus, evolved enormous wingspans that may have exceeded ten metres, making them the largest flying animals in Earth’s history.

To read a recent article about the discovery of a new species of Late Triassic pterosaur from North America: Is this America’s Oldest Pterosaur?

What is a Dinosaur?

Dinosaurs (Dinosauria) were a diverse clade of reptiles that dominated terrestrial ecosystems throughout most of the Mesozoic.  They evolved a huge variety of forms from tiny, bipedal insectivores to giant herbivores some of which were the largest land animals ever.  In addition, the Dinosauria includes armoured dinosaurs like Stegosaurus and meat-eaters such as the mighty Tyrannosaurus rex.

Everything Dinosaur Evolution T. rex model on top of its beautiful box. This is a 1:33 scale model of a Tyrannosaurus rex. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The picture (above) shows a 1:33 scale Tyrannosaurus rex figure.  It is a replica of the “King of the Tyrant Lizards”.

To view the Everything Dinosaur Evolution range: Everything Dinosaur Evolution Figures.

Dinosaurs are defined by specific anatomical features, especially in the hips and limbs. Pterosaurs evolved from a related reptile lineage, but they developed separately from dinosaurs.

Are Pterosaurs Related to Dinosaurs?

Yes. Pterosaurs and dinosaurs were closely related. Both belonged to a larger reptile group called the Archosauria. This group also includes modern crocodilians and birds. In addition, it includes basal members such as the aetosaurs (eagle lizards). However, scientists classify pterosaurs in their own group called the Pterosauria.

Remarkably, even teaching resources confuse pterosaurs with dinosaurs (see below).

Unfortunately, some of the dinosaur and prehistoric animal themed teaching resources available in the UK are wildly inaccurate. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Why Do People Think Pterosaurs Were Dinosaurs?

Many museums, films and books group pterosaurs together with dinosaurs because they lived during the same geological periods.  For example, museums often display pterosaur fossils next to dinosaur exhibits. In addition, many pterosaurs were spectacular animals with impressive wingspans. Some species, such as Quetzalcoatlus and Hatzegopteryx, had wingspans similar to small aircraft.

A drawing of the huge pterosaur Hatzegopteryx inspired by the CollectA Prehistoric Life Hatzegopteryx model. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

This often leads people to assume pterosaurs were dinosaurs.

The Key Difference Between Pterosaurs and Dinosaurs

The simplest answer is:

Pterosaurs were flying reptiles closely related to dinosaurs, but they were not dinosaurs. Scientists separate them because their anatomy and evolutionary history are different.

Mike from Everything Dinosaur commented:

“We hope this explanation helps. Collectors and dinosaur fans can explore a wide range of scientifically inspired prehistoric animal figures at Everything Dinosaur, including detailed replicas of famous pterosaurs such as Pteranodon and Quetzalcoatlus.”

The award-winning Everything Dinosaur website: Scientifically Accurate Models of Pterosaurs and Dinosaurs.