Dinosaurs Take to the Air
Pterosaurs, also referred to by many as “Pterodactyl’s” were the giant winged dinosaurs that graced the prehistoric skies from the late Triassic period through to the end of the Cretaceous period. The Pterosaur is perhaps one of the more terrifying prehistoric beasts in terms of the evolution of the dinosaurs. While the Pterosaur was certainly a carnivore it is less this fact and more the development of flight among such a large beast that strikes terror in to the heart of even the most avid dinosaur lovers. The Pterosaur also ranged so widely in size that it is obvious that this winged prehistoric beast took the skies by storm and wasted no time in diversifying itself to adapt to life in various areas of the land. But the question remains – where did this huge winged beast come from?
The Winged Lizard
The Pterosaur flew the skies of the prehistoric ages between 228 million years ago and 65.5 million years ago and certainly added a whole new dimension to the prehistoric era. The term Pterosaur translates to “winged lizard” and the common synonym Pterodactyl translates to “winged finger” which derives from the understanding that the wing of the Pterosaur attached to a large finger like protrusion from the creatures hand. As the earliest vertebrates to ever develop the power of flight these massive winged creatures bore little resemblance to birds and instead carried many more dinosaur characteristics than those of modern day birds.
While the Pterosaur lived in the ages of the dinosaurs they are not, however, considered to be dinosaurs as this term is reserved for the terrestrial prehistoric creatures and not those which took to the skies. In consideration of this fact though it is known that some of the Pterosaur species did in fact walk or run on the ground in addition to flying but this is something which will be examined later.
Many Different Kinds of Pterosaur
The Pterosaur included a wide variety of species of flying creatures including: Preondactylus, Pteranodon, Pterodactylus, Rhamphorhynchus and Quetzalcoatlus. It is known that there were at least sixty genera of Pterosaurs to date and fossils from Pterosaurs have been located on every single continent to date. Having the skill of flight enabled these large prehistoric beasts to become rather quickly widespread.
The Preondactylus is known for having a long tail and lived in the area of modern day Italy. The Preondactylus has shorter wings with a wingspan of 18 inches and is thought to have fed on fish. The first Preondactylus was discovered by Nando Buffarini in 1982.
The Pteranodon is one of the more commonly known Pterosaurs and is recognized as being one of the larger Pterosaurs to exist. The Pteranodon had a wingspan which ranged in size from 9-20 feet and it is known to have fed on fish after fossilized Pteranodons revealed fish bones in the stomach area. The first Pteranodon was discovered by Othniel Charles Marsh in 1870.
The Pterodactylus is known as being one of the toothed Pterosaurs with a large crest on the back of its skull. The Pterodactylus had a wingspan which averaged in at around 5 feet wide and is thought to also have fed on fish as well as smaller animals which it was able to capture with the assistance of its small teeth. The first Pterodactylus was the very first Pterosaur to be discovered in 1784 by Cosimo Alessandro Collini.
The Rhamphorhynchus is known by its particularly long tail with a diamond shaped vane at the end. The Rhamphorhynchus also had needle like teeth in its jaws and had a wingspan of around 6 feet wide. The Rhamphorhynchus is thought to have fed on fish and insects. The first Rhamphorhynchus was collected by Georg Graf zu Münster in 1825; it was recognized as a Pterosaur by Professor Georg August Goldfuss and given the name Rhamphorhynchus for the first time in 1830 by Münster.
The Quetzalcoatlus: 36 Foot Wings!
The Quetzalcoatlus is known as one of the largest specimens of Pterosaur and is also known as having a completely toothless jaw. The Quetzalcoatlus had a wingspan that ranged between 33-36 feet and is thought to have fed by scavenging already dead dinosaurs on the land. It is not thought that the Quetzalcoatlus was able to feed from skimming fish from the ocean like many other Pterosaurs as a result of its humongous size. Were the Quetzalcoatlus to try skimming it would not have the energy to fight the drag on it from flying so closely to the water in such a controlled movement. The first Quetzalcoatlus was discovered in Texas in 1971 by Douglas A. Lawson, a geology graduate student of the University of Texas at Austin's Jackson School of Geosciences.
How did These Giant Dinosaurs Fly?
The Pterosaur’s size varied based on which genera of Pterosaur is being discussed; however the Quetzalcoatlus is known to be one of the largest of the Pterosaurs with a wingspan of 33-36 feet! These incredibly large creatures were able to fly due to their leathery and muscular wings and their hollow bones; however, the exact mechanics behind the flight of the Pterosaurs are unknown at this time. One of the most difficult aspects of the Pterosaur for paleontologists to understand is how the ability of flight adapted. As of yet no middle link has been found to connect the much larger terrestrial reptiles to the huge Pterosaurs of the skies. It is hoped that future discovery of more complete Pterosaur specimens will aid in more detailed findings in regard to this missing link; however, until that middle man is found the Pterosaur remains as somewhat of a mystery in the line of evolution.
The Pterosaur did not just have amazing wingspans but they also had rather unique long jaws which resembled beaks. While most of the Pterosaurs did have teeth in their beaks some of the more advanced Pterosaurs did not. Another more impressive feature of the Pterosaur was the wide range of skull crests. Some Pterosaur crests were particularly elaborate and brightly colored although because these crests were composed, in large part, of keratin they did not preserve with fossils and are only detectable through the use of UV light photography. Due to the fact that most paleontologists do not utilize this tool when uncovering fossils the true extent of crests among the Pterosaurs was not fully understood for a long time.
Bird or Dinosaur?
Where the Pterosaur resembled dinosaurs in appearance they did; however, resemble modern day birds with their hollow bones and air sac respiratory system which ran much like the respiratory system of modern day birds. The Pterosaur also was known to have particularly large flocculi in the brain just like birds. The flocculus in the brain of these airborne animals is responsible for integrating joint, skin, muscle and balance organ signals and it only seems logical in a creature that depends so much on sensory awareness that this area of the brain should be larger. It should be noted though that in the Pterosaur the flocculi took up approximately 7% of the brain mass versus the usual 1 to 2% in modern day birds. It is no surprise though that the Pterosaur needed to utilize so much of its brain to discern these signals when they had a wingspan of up to 36 feet! To maintain control and sensory awareness of a wingspan so large the Pterosaur could have been in serious trouble were it to have the much smaller flocculus utilized by birds today!
Did Pterosaur Walk?
One aspect of the Pterosaur physiology that has raised quite a few questions among paleontologists is that of walking. While the Pterosaur were airborne for the majority of their lives they also found it necessary to walk on the ground and it is argued that these creatures were bipedal by one paleontologist camp and quadrupedal by another. It was presented by Kevin Padian in the 1980’s that perhaps the smaller of the Pterosaurs whose hind limbs were much longer could have utilized these longer legs for running bipedally. With Padian’s theory taken in to consideration though, it has also been proven through preserved Pterosaur track ways that some Pterosaurs also walked on all four limbs. It can be discerned from track ways that some of the Pterosaurs were quadrupedal since their hind feet had four toes and the front feet had three toes. When the Pterosaur was walking on the ground they showed the more humanlike characteristic of walking using the entire foot, whereas the larger dinosaurs tended to walk on their toes. The feet of the Pterosaur often tell much more about the particular genera than simply the mode of walking, it often times tells paleontologists the preferred environment of the Pterosaur in question as well. Pterosaurs with much larger feet are thought to have been native to much softer lands, perhaps even marshy lands where they were forced to wade. In contrast to the larger footed Pterosaur, Pterosaurs with smaller feet are thought to have been native to much harder land that was earthier than it was marshy.
One reason that the Pterosaur was forced on to the ground was feeding. The Pterosaurs were carnivores and fed on a wide variety of life but most likely was forced to bring its food to land in order to eat. In general the Pterosaurs ate fish, insects, crabs and some were even known as scavengers of dead land animals. The Pterosaurs weren’t only hunters; however, they were also hunted, in particular by Spinosaurids. Proof of the hunting of Pterosaurs by Spinosaurids can be found in the discovery of three cervical vertebrae of a Pterosaur which had a Spinosaur tooth in them.
Another reason that the Pterosaur was forced on to the ground was for egg laying. Not too much is known about Pterosaur mating and reproduction other than the fact that their eggs were most likely similar to those of the lizards of today with leathery shells rather than fragile shells. Paleontologists also believe that Pterosaurs buried their eggs much like modern day crocodiles in order to incubate them. It is also known from discovery of Pterosaur eggs that the younger Pterosaurs were born with the ability to fly, or else it was acquired very soon after hatching. Due to this rapid acquisition of the ability fly it is not believed that the Pterosaur was a particularly doting parent. Some paleontologists even believe that the Pterosaur hatchlings were able to feed themselves from their yolk upon hatching and consequently never depended on adult Pterosaurs for food.
When and Where did Pterosaur Live?
The Pterosaur is known to have lived throughout North America, Europe, Africa and Australia. The very first Pterosaur fossil discovery came in 1784 in Bavaria, Germany. This fossil was found by Cosmo Alessandro Collini and at the time was thought to be a marine based creature; however in 1809 Georges Cuvier determined the specimen to be that of “pterodactyle.” This is where the common name for the Pterosaur was coined. While quite a few Pterosaur fossils have been located to date there remains the problem of posterity. Due to the fact that the Pterosaurs had hollow bones the Pterosaur fossils are often crushed by settling sediments. Crushed bone samples are much harder to ascertain any information from for obvious reasons. Some Pterosaur specimens do manage to survive by being encapsulated by sediment rather than crushed by it but these specimens are unfortunately fewer than those which get crushed.
With the smallest of known Pterosaurs measuring in at about the size of a small bird and the largest measuring in with a 36 foot wingspan there was certainly a lot of variety among these large airborne creatures. The most amazing fact about these large carnivores, however, remains their very coming in to existence. Without any hard evidence as to the missing link between the large terrestrial dinosaurs of the Triassic and Cretaceous periods and the huge airborne Pterosaurs paleontologists are left with a significant gap in evolution. Some may compare this gap to that assumed between homo sapiens and apes and whether or not this seems relevant there is still the question of that missing link – where did these giant flying creatures come from? What spawned the evolution of the flying carnivores?