What is Archaeopteryx

Origin and evolution of various life forms is an area that has always intrigued the human intellect. The discovery of the fossil of Archaeopteryx - the part reptile and part bird-like creature, finally helped man complete the baffling jigsaw puzzle of evolution of birds. Although a number of related fossils have been discovered over the years, the most significant discovery was made in the year 1861 when the first skeleton known as the London Specimen was unearthed in Germany. This discovery occurred just two years after Charles Darwin released his book On the Origin of Species. Hence, it was a significant event that provided credibility to the theory of natural selection.

Habitat and Diet

Archaeopteryx was a crow-sized early bird that belonged to the Jurassic Period. It lived some 150 million years ago in the southern regions of present day Germany. Europe in those times was a chain of islands, and the Solnhofen area (in Germany) which has the largest concentration of the fossils was a lagoon. Archaeopteryx probably lived on the low lying islands around the lagoon, and when they died they were preserved as beautiful fossils in the anoxic waters (water containing little or no oxygen) of the lagoon. These islands were semi-arid regions with long dry seasons and little rain. Although fossilized remains of tree trunks have been found, it is believed that these areas lacked large trees. As far as their diet is concerned, Archaeopteryx were carnivorous birds that fed on small animals and insects.

The Missing Link

Archaeopteryx means ancient wings. Despite the presence of feathered wings that make it a prominent member of the avian family, one should not lose sight of the distinctly reptilian features of Archaeopteryx. Unlike modern day birds, Archaeopteryx had teeth, a long bony tail, three claws on each wings, belly ribs and a cartilaginous breastbone (sternum). However, besides the feathers for flight, the Archaeopteryx had a wish bone, reduced fingers and a light body made of hollow bones that makes it more of a bird than a reptile. In fact, Thomas Henry Huxley compared the fossilized remains of this prehistoric bird and Compsognathus - a bird-like dinosaur, and concluded that Archaeopteryx is a transitional bird that shared a common ancestor with the dinosaurs.

More of a bird

Though modern birds lack teeth, early birds, mainly those of the Mesozoic period had teeth. Although Archaeopteryx had a typical non-avian characteristic - the tail, in the embryo of certain modern day birds a large number of vertebrae are observed. Some of these vertebrae fuse to form a bone called the pygostyle. The most important bird-like feature is the presence of the flight feathers. The flight feathers of Archaeopteryx were distinctly asymmetrical and structurally similar to the modern day birds. The tail feathers were also less asymmetrical with strong vanes supporting them.

To Fly or Glide?

Despite the presence of well-developed flight feathers and other bird-like features, one can't be sure if Archaeopteryx was just a glider or could fly long distances. Absence of a bony breastbone did not make this prehistoric a strong flier. However, strong flight muscles could have been attached to its well developed, boomerang shaped wishbone. In modern birds the shoulder joint is more dorsally positioned than that seen in Archaeopteryx fossils. This allows modern birds to lift their wings above their body for the upstroke necessary for flapping flight. However, the shoulder joint in these ancient birds had a more sideways orientation that did not allow them to raise their wings high. Hence, this arrangement did not provide for upstroke of the wings as in modern birds. However, Archaeopteryx wings were capable of executing downstroke which allowed them to at least glide, if not fly freely like present day birds.

The discovery of the fossils of Archaeopteryx has been an important event in the history of evolutionary studies. Not only did it bolster the theory of evolution, it also answered the bewildering question 'Where did birds come from?'