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The origin of flying feathered birds lay in the scales of prehistoric reptiles

Posted in Animals, Dinosaurs, Geography, Historical articles, Prehistory, Wildlife on Thursday, 19 December 2013

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This edited article about prehistoric animals first appeared in Look and Learn issue number 498 published on 31 July 1971.

Archaeopteryx, picture, image, illustration

Archaeopteryx by Roger Payne

The world has not always been as it appears today. Were we able to travel back in time for 600 million years, the continents and seas would be completely unfamiliar to us.

The largest land mass today is Eurasia, stretching half way round the globe, with one arm pointing towards America and a broad leg thrust down into Africa. Yet this huge continent was, 600 million years ago, an archipelago of large islands that rose slowly from the sea to merge into the super-continent of Laurasia, a great land mass that extended right across the world to include North America.

According to many scientists, who hold to the idea of drifting continents, Laurasia formed the northern block of a world continent, partially divided in the middle by the Tethys Sea. The southern half of this land mass was called Gondwanaland, which consisted of South America, Africa, India and Australia.

This condition existed in the Carboniferous Period, 230 million years ago. Opinions are divided as to when the separation of the continents began; some think as early as the Jurassic times (170 million years ago). Others believe it was much later in the Cretaceous times, 135 million years ago, that the first cracks appeared in the world’s structure.

Of course these movements were so slow that no living thing would have noticed them. In fact, many think that it was only in the Pleistocene Epoch, around a million years ago, that the rift between Africa and South America widened enough to become the Atlantic Ocean.

The drifting of the continents, caused by complicated movements of convection currents beneath the earth’s crust, have had much to do with orogeny (mountain building) and it is clear that, during the earth’s long history, several driftings have occurred before that, originating in the Tertiary Era.

There are two recognised directions in which these movements have taken place – westwards, when the Americas separated from Africa, and later from Eurasia. This caused the folding and upthrust of the Andes and the Rocky Mountains, and secondly, the movement towards the equator by Eurasia from the north and Africa and India from the south. This enormous pincer movement squeezed up the Atlas Mountains in Africa and the Alps and Himalayas in Eurasia.

It is thought that older mountain ranges were brought into being by other driftings in the even more distant past.

Two features persisted over a very long period. They were the Tethys Sea (which separated Europe from Africa, and India from the main body of Asia), and the much narrower Uralian Sea that flowed down from the Arctic to join the Tethys and divided Europe from Asia.

It was not until 36 million years ago, in the Oligocene Epoch, that the great Tethys began to regress from Eurasia so that all that remains of it today is the Mediterranean and the inland seas of Caspian, Aral, Azov and the Black Sea. The narrower sea of Uralia also dried up and from then on Europe and Asia have been one continent.

But let us return to the Jurassic Period, when the Tethys Sea covered large areas of Europe, for then shallow lagoons abounded and a tropical climate covered the land.

Coral reefs flourished in the warm waters and, when the tide fell, the wind blew a fine white dust off the reefs to accumulate on the bed of the lagoons, forming layers of fine white mud that gradually hardened into limestone.

This became the famous Solenhofen lithographic stone in which perfect specimens of ancient life were preserved. Even the delicate veins of dragonfly wings, the structure of jellyfish and the casts of worm tunnels were all clearly imprinted in the stone.

Here, too, were found the beautiful fossil bones of many kinds of flying reptiles – the leathery-winged Pterosaurs that were the first adventurers of the air, and whose flying-webs were useless if once torn. When that happened over the water, it meant a quick grave in the gelatinous mud of the lagoon and another Pterosaur was preserved for time’s museum.

But the Solenhofen limestone contained fossils of even greater interest than the Pterosaurs and their kind.

In 1861, two years after Charles Darwin had published his famous book, The Origin of Species, a fossil feather was found in the lithographic limestone quarry near Solenhofen.

At first the discovery was pooh-poohed by the palaeontologists, for no one at that time believed that birds existed in Jurassic days.

However, only a month after the finding of the feather, the incomplete skeleton of a reptile with a long tail and the clear imprint of feathers on it turned up in the same district.

This find created an uproar in scientific circles, for it proved, without doubt, that birds had evolved from reptiles and were not a separate creation, as the anti-Darwin critics affirmed.

The finding of Archiopteryx, or Ancient Wing as it was named, did much to advance Darwin’s theory of evolution for, while Archiopteryx had some bird-like features, besides that of feathers, its skeleton was also distinctly that of a reptile. Had it not been for the fortunate accident that the creature was buried in a fine-grained mud that held the imprint of feathers, it would have gone down in fossil history as just another crowsized reptile, of which many were in existence during the Jurassic Period.

This period was a very important one for the evolution, all over the world, of that group of extinct reptiles known as the Dinosaurs. To Europe, and especially to the British Isles, fell the distinction of finding the first dinosaur to be scientifically described.

In March, 1822, a Doctor Mantell and his wife were visiting a patient near Lewes in Sussex. To pass the time, while the doctor was in the house, Mrs. Mantell strolled up and down the country road. Noticing an object shining in some stones (left by workmen for repairing the road), Mrs. Mantell went to investigate, and found that it was an unusual shaped tooth.

Knowing that her husband was interested in fossils, Mrs. Mantell showed it to him. The large tooth so aroused the doctor’s curiosity that, for some weeks afterwards, he returned to the place where it had been found and, to his delight, not only discovered further teeth but also some large fossilised bones, none of which was familiar to him.

At that time no one had heard of dinosaurs. In fact, the existence of a great race of extinct reptiles was unknown even to the scientific men of the day.

After much thought, Doctor Mantell sent his fossils to the great Baron Cuvier in Paris, who was the most famous authority of the time on backboned animals. The Baron declared that the bones were those of an extinct hippo and the teeth those of an extinct rhino!

This did not satisfy Doctor Mantell, who took the teeth to the Royal College of Surgeons’ Museum in London, and began comparing them with specimens there of other animals.

It was here, by chance, that he met a Mr. Sutchbury, a naturalist just returned from studying the Iguana lizard in Central America. Mr. Sutchbury at once recognised the likeness between the lizards’ teeth and the much larger fossil ones belonging to the doctor. Having at last found out what he wanted, the learned doctor then wrote a paper on his famous teeth, giving them the name Iguanodon which means literally “Iguanatooth.”

From these bones and a few fragments found in Kent, the scientists built up a reconstruction of the giant Iguanodon. It was, however, completely wrong, for it represented a big reptile on all fours, while the bony spikes that should have adorned its thumbs, were stuck on its nose!

Some years later, however, a remarkable quantity of over 20 Iguanodon skeletons were found in a Belgian coal mine. These enabled palaeontologists to make complete and accurate reconstructions of this famous dinosaur.

The name Dinosaur was coined in 1842, when Richard Owen, the first great name in British vertebrate palaeontology, wrote a report on British fossil reptiles suggesting the name of Dinosauria for the sub-order of great extinct saurians.

Not many years after, the name Dinosaur became a word of common knowledge, and most school children today probably know more about the Terrible Reptiles than did the learned men of the early 19th century.

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