Pterosaurs, (pronounced "TARE-uh-soars") meaning winged lizards, were flying reptiles of a group of organisms consisting of a single common ancestor and all the descendants of that ancestor called Pterosauria.
Pterosaur Characteristics
They existed from the late Triassic to the end of the Cretaceous Period (228 to 65 million years ago). Pterosaurs were the first vertebrates to evolve flight. Their wings were formed by a sophisticated, thin membrane of skin that stretched from elongated fingers on their forelimbs to the end of their hind limbs. In the air, they were masters of flight, relying on updrafts (rising warm air) and breezes to help in flying,
yet on ground they appeared very cumbersome and clumsy as their legs were joined up by their wings. Their bones were hollow and air filled very lightweight like the bones of birds. Earlier species had long, fully-toothed jaws and long tails, while later species had a highly reduced tail, and some lacked teeth.
Unlike typical reptiles, Pterosaurs had a keeled breastbone that was developed for the attachment of flight muscles and a brain that was more developed than comparable dinosaurs of similar sizes.
Pterosaurs had been around for 100's of millions of years, flying above a world ruled by dinosaurs. It was during the beginning of the Cretaceous period, 127,000,000 BC, that the breaking up of the two massive north and south continents began, and what was once solid ground was now being replaced by coastal ragged cliffs. This occurrence increased the presence of flying reptiles. Not only did they increase in number due to more breeding grounds appearing around the coastal areas, they also increased in size. These huge flying reptiles became the 'Kings of the Sky' with wingspans reaching 6 metres or more. One particular species that dwarfed them all was the Ornithocheirus which is featured below.
However, modern bats and flying squirrels show considerable variation in the extent of their wing membranes and it is possible that, like these groups, different species of pterosaur had different wing designs. Many if not all Pterosaurs also had webbed feet, and although these have been considered to be evidence of swimming, webbed feet are also seen in some gliding animals to have had an aerodynamic function.
Pterosaur Diet
Pterosaurs were carnivores; they ate fish (which they caught at the surface of the oceans), mollusks, crabs, perhaps plankton (for some species), insects, and scavenged dead animals on land.
Pterosaur Mating
Most Pterosaurs returned to the same breeding ground at the same time every year. Each individual would try to head for it's same mating spot where it had mated in previous years. They would gather, and compete noisily for their particular spot. The more central they were at the breeding site, the more chance they had of attracting a mate. Many older Pterosaurs returning to the breeding ground eventually had to land elsewhere as their positions had been taken over by younger members of their species. Some were banished to the outskirts and were lucky to attract a mate at all.
Male Pterosaurs had a crest on their long beaks, some crests would flush with bright colours which would help to attract a female. The more colourful the crest, the more chance a male Pterosaur had of finding a mating partner. Female Pterosaurs did not have crests. Mating was usually very brief, females would approach a potential mate in submission and after mating briefly would again take to the skies while the male continued to attract more females. These mating periods usually lasted for around three days, then all the males would begin subsiding from the breeding ground until the same time the following year.
In this Dinosaur Den special feature, we are going to take a look at some of the smaller species of Pterosaurs and also at some of the magnificent beasts that ruled the skies supreme. Below are some popular Pterosaurs in alphabetical order.
Dimorphodon
Dimorphodon (pronounced: die-MORF-oh-don) meaning ("Two-form Teeth") was a genus of medium-sized pterosaur from the Early Jurassic Period. It belonged to the Order 'Pterosauria', Suborder 'Rhamphorhynchoidae' and belonged to the Family 'Dimorphodontidae'.
It was named by paleontologist Richard Owen in 1859. Dimorphodon means "two-form tooth" referring to the fact that it had two distinct types of teeth in its jaws - which is comparatively rare among reptiles. Fossil remains have been found in England. Mary Anning (1799 - 1847) was famous for her Dimorphodon discovery at Lyme Regis in Dorset, UK. This region of Britain is now a World Heritage Site, dubbed the Jurassic Coast. Dimorphodon was approximately 1 metre (3.3 ft) long, with a 1.2 metres (4 ft) wingspan.
It has been argued that Dimorphodon was a biped, though fossilised track remains of other pterosaurs (ichnites) show a quadrupedal gait while on the ground. Its teeth and jaws suggest it was, like most pterosaurs, a piscivore (fish eater). Most depictions display a puffin-like 'beak'.
Unlike most other pterosaurs, Dimorphodon's legs sprawled out at the sides. making its walking gait clumsy. This might indicate that Dimorphodon spent much of its non-flying time hanging from cliffs or tree branches, holding on with its toe claws.
Dimorphodon lived approximately 200 million to 180 million years ago.
Eudimorphodon
Eudimorphodon (pronounced: YOU-di-morf-o-don) was a pterosaur that lived around present Italy during the Middle Triassic. It belonged to the Order 'Pterosauria', Suborder 'Rhamphorhynchoidae' and belonged to the Family 'Campylognathoididae'.
It had a wingspan of about 100 centimetres and at the end of its long bony tail was perhaps a diamond-shaped flap. The flap may have helped it steer while in the air. It showed a strong dimorphism of the teeth, hence its name "true dimorphic tooth". It had large eyes, a short neck, many sharp teeth in pointed jaws (for eating fish and insects).
The species, then the oldest pterosaurian known, was found in 1973 by Mario Pandolfi and described that same year by Rocco Zambelli. Despite its age it has few primitive characters.
To observe an Eudimorphodon flying, click HERE. Page will open in new window, close when finished.
Ornithocheirus
Ornithocheirus (Pronounced: or-NITH-oh-KIE-rus) was a magnificent beast. This huge Pterosaur dwarfed all other Pterosaurs and ruled the skies supreme. Along with Quetzalcoatlus, several large bone fragments from the Santana Formation of Brazil indicate that Ornithocheirus would have been the largest pterosaurs that ever lived. It existed in South America during the early to the late Cretaceous period. It belonged to the Order 'Pterosauria', Suborder 'Pterodactyloidea' and belonged to the Family 'Ornithocheiridae'.
It had a wingspan of 12 metres (40 feet) from wing tip to wing tip and a body larger than a man's. It would have been approximately 3.50 metres (11.5 feet) long (1.50 metres (5 feet) of which belonged to the head) and stood approximately 3 metres (10 feet) tall when on the ground on all fours. Despite this, the creature would only have weighed as much as (100 kg), thanks to hollow bones filled with air sacks.
Ornithocheirus could make fantastic journeys to reach it's breeding site which could have been on the other side of the world. It would travel from South America to Europe, gliding over 1000's of tons of dinosaurs and across Atlantic seaways to mate each year as it had always done. These long journeys, however, could have their setbacks. The climate was warm and tropical and there were only two seasons, wet and dry. Should it have been the wet season during the Ornithocheirus's flight, it would have spelt disaster for this migrating Pterosaur.
During heavy rain, the Orinthocheirus would have to stop his journey and shelter. The fine, downy fur on his body needed to be kept dry and to be able to find a mate at the breeding site, his body would have had to have been in prime condition. When rains halted, Ornithocheirus could resume his long journey, however, the warm updrafts of air would have had to be strong enough to lift him into flight.
Like most Pterosaurs, Ornithocheirus would show the first signs of mating when faint colours appeared on his crest.
Feeding along the way was essential for the Ornithocheirus in order to keep up his strength. The young Atlantic, still only 300km wide at that time, was a water teeming with fish, but flying low to feed had it's dangers too, as their were plenty of huge sea reptiles, such as Liopleurodon, who would have made a meal out of him.
Like all giant Pterosaurs, Ornithocheirus used his huge wings to ride the warm air currents over land and sea, and with their lightweight bodies, they would glide effortlessly over huge distances. They could spend an entire day on the wing traveling as far as 14,000km per day.
At the breeding site the huge crest on the beak flushed with blood, so as to impress the females who bore no crest at all. (Pterosaur mating, above).
Pteranodon
Pteranodon (pronounced: Teh-RAN-uh-DON), from the Late Cretaceous (santonian-campanian, 85-82 million years ago) of North America (Kansas, Alabama, Nebraska, Wyoming, South Dakota) was one of the largest pterosaur genera. They were about 6 feet (1.8 metres) long, had a 25-33 foot (7.8-10 metres) wingspread, and weighed about 35 pounds; its standing height was about 6 feet (1.8 metres).
They had large brains and good eyesight. Some pteranodons had long, light-weight, bony crests on their heads that may have acted as a rudder or stabilizer when flying, or may have been a sexual characteristic. They had no teeth.
Pteranodon wings were covered by a leathery membrane. This thin but tough membrane stretched between its body, the top of its legs and its elongated fourth fingers, forming the structure of the wing. Claws protruded from the other fingers.
It belonged to the Order 'Pterosauria', Suborder 'Pterodactyloidea' and belonged to the Family 'Pteranodontidae'. Other species including the slightly smaller P. sternbergi, had a wingspan of 6 metres (20 feet).
Unlike earlier pterosaurs such as Rhamphorhynchus and Pterodactylus, Pteranodon had toothless beaks, like modern birds. Although they had no teeth, Pteranodons were carnivores. They ate fish (which they caught at the surface of the oceans), mollusks, crabs, insects, and scavenged dead animals on land. They may have hunted like modern-day pelicans, scooping fish out of the water and swallowing them whole.
Pteranodon fossils have been generally found in the Cretaceous chalk beds of Kansas. These chalk beds were deposited at the bottom of what was once an epicontinental seaway on what is now the North American continent. The first Pteranodon skull was found on May 2, 1876, in Smoky Hill River, Wallace County, Kansas, USA, by S. W. Williston, a fossil collector.
Pteranodon were reptiles, but not dinosaurs, like all other Pterosaurs.
Rhamphorhynchus
Rhamphorhynchus (pronounced: RAM-fo-RING-khus) was a long-tailed pterosaur of the Jurassic period. Its name means 'beak jaw'. Only 17.5 cm (7 in) long but with a wingspan of 100 cm (3 feet), it was less specialized than the later pterodactyloids. It had a long tail stiffened with ligaments which ended in a diamond-shaped vane.
It belonged to the Order 'Pterosauria', Suborder 'Rhamphorhynchoidea' and belonged to the Family 'Rhamphorhynchidae'.
This meat-eater had long, narrow jaws with sharp teeth that pointed outwards. It had tiny legs.
Rhamphorhynchus ate fish and it is believed that one of the ways it hunted was by dragging its beak in the water, catching fish and tossing them into its throat pouch, a structure similar to that of pelicans, which has been preserved in some fossils. This method of catching fish is found today in skimmers.
Tapejara
Tapejara (pronounced: TAP-ah-JAR-ah) (from a Tupi meaning "the old being") is a genus of Brazilian pterosaur from the Cretaceous Period. The Tapejara genus showed wide diversity in size, and each species bore a differently sized/shaped crest that may have been used to signal and display for other Tapejara, much as toucans use their bright bills to signal to one another.
It belonged to the Order 'Pterosauria', Suborder 'Pterodactyloidea' and belonged to the Family 'Tapejaridae'.
There were three species in this family:
T. wellnhoferi
T. imperator
T. navigans
Tapejara crests usually consisted of a semicircular crest over the snout, and a bony prong which extended back behind the head. The largest species, T. imperator, sported another long, thin prong that extended from the snout crest.
Tapejara's were colourful Pterosaurs and bizarre looking creatures. As it suggests above, their bright coloured crests would be used for signaling and also for attracting females from the sky during mating season. Perching on ragged cliffs, Tapejaras would flush their crest with blood to entice females from the air. Similar mating occurred to that of other Pterosaurs, whereby, a good central position would guarantee a mate. Some, however, secured a less central position and therefore had less chance of attracting a mate.
During the late creataceous period, birds began to flourish - these kind of birds were relatives of the carnivorous Raptors. Instead of scales covering their bodies, they had evolved feathers and their arms had turned into wings. Cretaceous birds were very aggressive and would attack intruders to their grounds, particular if there were eggs to protect. To a huge Pterosaur like the Ornithocheirus, these birds looked as small as insects. However, their tiny wings were more resistant than the thin skin membranes of the Pterosaurs wings.
In the far future, the huge kings of the skies would surrender the skies - to the birds.
Special feature 1 Jurassic Seas: December 2006
Special feature 2 - Kings Of The Skies: January 2007
Special feature 3 - Early Mammals: February 2007
