Pterosaurs

Pterosaurs are commonly referred to as “flying dinosaurs” as they were around during this period and many have confused some of these species with dinosaurs. Pterosaurs are said to have been close cousins of the dinosaurs but they are on a completely separate branch of the family tree for reptiles.

The name pterosaur, as a lot of the species of this era were named, comes from the Greek language of “pteron” meaning wing, and “sauros” meaning lizard.

Pterosaurs were on earth from 228 to 66 million years ago which means they existed from the Jurassic period right through to the Cretaceous period before becoming extinct. During this time as dinosaurs ruled the earth, the pterosaurs ruled the skies.

Aerodactylus Image source and artist 

Birds of today did not descend from pterosaurs as some people may think. Many were not feathered, like the modern flying Aves (warm blooded vertebrates), and instead had more reptile features with most being cold blooded. There have been some species that have been found with fossilised hair fragments which has made scientists believe they needed the hair to keep themselves warm. So even now we are learning all the time which is why this subject is fascinating.    

Probably the most famous pterosaur was the pterodactyl, and thanks probably due to the media and Hollywood’s portrayal of this flying reptile. But interestingly the pterodactyl was not actually a single species, it is a common word that is associated with two pterosaurs, the Pteranodon and the Pterodactylus. 

Pterosaurs had a variety of different diets, some species were predominantly fish eaters, some may have hunted land animals, some may have hunted each other, while others stuck to a diet of fruit.

Characteristics of pterosaurs

Compared to modern day vertebrae flying groups such as bats and birds, the pterosaurs had large skulls and long jaws filled with sharp teeth. As time went on and the species evolved their jaws became longer.
A distinguishing feature of the pterosaur was their crests that were located on their heads. They came in many ways, some crests were thick with large bones, some were thin, and small with no underlying bone and were fleshy.

Their most distinguishing features, and the most obvious was their wings. These were formed by bones, membranes of skin, and other tissues. The wings were often attached to the fourth finger on their claws. As time went on many species evolved and became efficient for flying. They probably got slower, but meant they were more effective for flying longer distances.

Tim Evanson, CC BY-SA 2.0, via Wikimedia Commons

Sizes of pterosaurs

As mentioned above the sizes ranged hugely. The smallest pterosaur discovered so far is the Nemicolopterus crypticus and was discovered in China, and had a wingspan of only 10 inches (25 cm).

One of the largest pterosaurs species discovered was called the Quetzalcoatlus who had a wingspan estimated to be 11 to 12 meters (33 to 36 feet) wide.

Its thought this was the biggest known flying animal that was ever on the planet. It has been referred to as the “winged monster” due to its enormous size.

Giants over time. © Mark Witton “Record claims of pterosaur wingspans and equivalent standing heights compared to ( a ) a 3 m span Andean condor ( Vultur gryphus ) and ( b ) a 3 m span wandering albatross ( Diomedea exulans ). ( c ) Marsh’s (1876 a ) 7.6 m span Pteranodon longiceps . ( d ) Stoyanow’s (16 November 1936, Time Magazine ) apocryphal 10 m span Jurassic pterosaur. ( e ) Harksen’s (1966 ) 9.1 m span Pteranodon sternbergi . ( f ) Lawson’s (1975) 11 m span Quetzalcoatlus northropi . ( g ) The Buffetaut et al. (2002) 12 m span Hatzegopteryx thambema . ( h ) The erroneously reported BA Festival of Science 20 m span pterosaur. Humans used for scale are 1.75 m tall.” Link to resource.

Pterodactyl

Pterodactyl was not actually classed as a dinosaur but as a pterosaur (flying reptile). While dinosaurs ruled the land, pterosaurs ruled the skies for millions of years. Interestingly pterodactyl is the common word many associate with two pterosaurs, Pteranodon and Pterodactylus.

IMPORTANT!

They were not actually closely related to each other and pterodactyls are the name referred to these mainly by journalists and fiction. Pterodactyl’s could not be left out from this website though as it is probably the most famous flying reptile of that period.

Barbaridactylus image source and artist

About pterodactyl (Pterodactylus)

The name “Pterodactylus” originates from the Greek language meaning “wing” (ptero) and “finger” (dactyl) and was given the name by Constantine Samuel Rafinesque, a French genius who wrote and studied a variety of historical topics.

Pterodactylus lived during the late Jurassic period between 150.8 to 148.5 million years ago.

There have been over 30 fossil specimens to date with quite a few of them having been well preserved.

• Pterodactyl’s were not actually dinosaurs, they were a distant cousin.
• Pterodactyl’s were a species that came under the broader family of Pterodactylus.
• The first pterodactyl specimen was discovered in 1784 by Cosimo Alessandro Collini, who was an Italian scientist.

• Most of the fossils of the pterodactyl have been found in Bavaria, Germany
• The majority of pterodactyl’s in comparison to today, were the size of eagles or hawks.
• Pterodactyl’s wingspan was up to 1m (3.3 feet)

• Pterodactyl’s lived about 150.8 to 148.5 million years ago in the late Jurassic period
• Pterodactyl was not actually a dinosaur. Dinosaurs  
• The pterodactyl was thought to mainly feed off fish, although scientists have stated they also fed off small animals. 

Pteranodon

Pteranodon was one of the two species of pterosaurs that identified with the pterodactyl. The Pteranodon lived during the late cretaceous period 88 to 85 million years ago.

There have been more fossils of pteranodon found than any other pterosaur, and at time of writing that number is around 1200.

Pteranodon Image source and artist

Pteranodon key features

The Pteranodon male was one of the largest pterosaurs there was. The male Pteranodon had an average wingspan of 5.6m (18 feet) but some were over 7 meters (23 feet). With so many specimens available various studies have been conducted by scientists to determine the weight of the Pteranodon. Some estimates have the average weight being as low as 20 kilograms (44Ib) while others stated estimates as high as 93 kilograms (205Ib).

Like a lot of other pterosaurs, the Pteranodon probably took flight from a standing position and used their forearms to push themselves into the air. Researchers even thought that their brains appeared to evolve for the flight as their lobes grew over time and their job was to process data from the wing membrane.

One of the main features of the Pteranodon was its skull crest. It has been debated for years what the role of these crests was for, and some scientists believed it was to counterbalance the jaws, or for helping to steer whilst in flight.

Modern day technology has helped with the hypothesis as scientists have used wind tunnels to replicate how the crest works in flight. It is thought that the crest was larger in males and smaller in females, and other experts have concluded that its primary function was for display, and the males used their crests to showcase themselves for the female Pteranodon.

Another characteristic of the Pteranodon was the narrow neutral spines on its vertebrae and they had relatively short tails compared to other Pterosaurs. As its name states, the Pteranodon lacked teeth, and any toothless jaw fossils of pterosaurs were associated with the Pteranodon for this reason.

Where it lacked teeth the Pteranodon made up for with its imposing skull. There was one species that had a head of 1.8 meters (5.9 feet) in length.

régine debatty, CC BY-SA 2.0, via Wikimedia Commons

Quetzalcoatlus key features

All fossils of the Quetzalcoatlus have been found in land and so conclusions have been made by some experts that they preyed on carcasses of dinosaurs. They have been found approximately 250 miles (400km) inland which is the reason for scientists to come up with this conclusion.

Some have said the Quetzalcoatlus fed off fish in rivers or lakes but there are no indications that these existed during the Cretaceous period and the energy it expelled hunting for fish was said to be huge, given its size.

How big was the Quetzalcoatlus?

It’s estimated the Quetzalcoatlus’s wingspan was between 11 to 12 meters (33 to 36 feet). As mentioned previously it has been referred to as the “winged monster” due to its enormous size.

The first discovery by Douglas Lawson remains one of the largest found to date and Lawson actually found more in the coming 2 years from a site 40km (25 miles) away from the first.

The explosive power needed for the Quetzalcoatlus to launch itself would have been immense. They would have launched in a single leap and would have only needed a few flaps of their enormous wings to keep them in the air. Some substantial research has gone into the estimations of flight speeds, altitude, and distance the Quetzalcoatlus could fly.

Matt Martyniuk (Dinoguy2), Mark Witton and Darren Naish, CC BY 3.0, via Wikimedia Commons

Hesperornis

Hesperornis was a huge bird that measured 6.5 feet (2 metres) in length. They had virtually no wings and hunted in the waters of the North American Inland Sea, swimming with powerful hind legs. Its feet were probably lobed rather than being webbed as in today’s grebes.

Like other Mesozoic birds such as Ichthyornis, Hesperornis had teeth in its beak which were used to hold prey such as fish.

Nobu Tamura (http://spinops.blogspot.com), CC BY 3.0, via Wikimedia Commons