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Prehistoric lizards which changed into birds

Posted in Animals, Birds, Historical articles, History, Prehistory on Wednesday, 27 February 2013

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This edited article about prehistory originally appeared in Look and Learn issue number 164 published on 6 March 1965.

Prehistory, picture, image, illustration

The age of terrible Lizards

During the Carboniferous period, which began about 280 million years ago, rich vegetation in the form of ferns and palm-like trees started to cover the land. The climate throughout the world was hot and moist and on the shores of the continents there were vast swamps.

These conditions continued into the Permian period, which is sometimes called the Upper Carboniferous period. A warm climate and plenty of vegetation were all that was needed for the development of land animals (top illustration).

These first land animals were amphibians which divided their time between the land and the water.

One of them, the Stegocephalus, would not be out of place in the world today. It was a newt-like creature about three feet long which crawled along the soft ground or paddled in shallow pools.

Its body was clad in an armour of strong scales and its flat head was armed with sharp teeth. For the stegocephalus was a fierce cannibal that fought and ate its own kind.

Other animals of that far distant period were quite unlike any creature we know. One of the largest and strangest was the edaphosaurus.

The edaphosaurus was the giant of its day, sometimes growing to a length of ten feet or more. Its most characteristic feature was the enormous comb or frill of body spines that ran along its back.

Although they looked so terrifying, edaphosaurus were timid, inoffensive creatures. Because of their tiny teeth they ate nothing but plants.

Both the stegocephalus and the edaphosaurus hatched from eggs laid by the females in swampy pools and spent the early part of their lives in the water. Like all amphibians, they were descended from fish of the Devonian period that through millions of years had adapted themselves to life on land.

The world of the stegocephalus and edaphosaurus also saw the first insect. This was the meganeura, a gigantic dragonfly with a wingspan of two feet.

Once animals appeared on the land they developed at an astonishing rate, not only in numbers but in size. By the time of the Triassic period (lower illustration) which began 190 million years ago, the most fantastic animals began to appear.

These were the dinosaurs, or great reptiles. The name “dinosaur” comes from two Greek words: deinos, meaning “terrible,” and sauros, meaning “lizard.” That is exactly what the dinosaurs were, great lizards.

But the dinosaurs were not so terrible as their name and appearance suggests. They were very stupid and most of them were timid and inoffensive. All they wanted was to be left in peace to eat the tons of greenstuff that made up their daily meals.

Another fantastic creature of the dinosaur age was the struthiomimus. This animal was much smaller than other monsters. It had long hind legs, very short forelimbs and a long tail. It ran and jumped in much the same way as the kangaroo of today.

It was during the era of the dinosaurs, which lasted for many millions of years and included several geological periods, that the first birds appeared. One of these was the rhamphorhynchus, but if you saw one today you would hardly recognize it as ancestor of all the graceful and colourful birds now flying in the world.

The rhamphorhynchus was simply a dinosaur lizard that through millions of years learned to fly. It was most probably descended from a species of the small, kangaroo-like dinosaurs.

Constantly running about to escape the flesh-eating reptiles and beating the air with their short forelimbs, they developed a fringe of scales on their forelimbs. This helped to take the weight of their bodies off the ground.

Eventually they took to living in trees for safety, and then learned to glide from branch to branch. In the course of millions of years they progressed from gliding through the air to flying in it.

You may find it difficult to imagine that the birds of today are descended from the clumsy flying reptiles of 180 million years ago. Nevertheless, our birds still have traces of their reptile ancestors.

Birds’ feathers lie flat on their bodies like overlapping scales and their beaks are not unlike the toothless mouth of a lizard, although the rhamphorhynchus had a row of huge teeth in its beak. But one of the most striking proofs of the reptile ancestry of today’s birds are the scales on their legs and toes.

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