Archaeopteryx sometimes referred to by its German name “Urvogel” ("original bird" or "first bird"), is the earliest and most ancient bird known. The name derives from the Ancient Greek (archaios) meaning "ancient", and (pteryx), meaning "feather" or "wing". Archaeopteryx lived in the Late Jurassic Period (4 million years ago) around 150 million years ago, in what is now southern Germany during a time when Europe was an archipelago of islands in a shallow warm tropical sea. Archaeopteryx possesses both reptilian and birdlike features, providing forceful evidence that birds originally evolved from dinosaurs. Archaeopteryx could grow to about 0.5 meters (1.6 ft) in length.
Archaeopteryx plays an important role not only in the study of the origin of birds but in the study of dinosaurs. It was named from a feather in 1861. That same year, the first complete specimen of Archaeopteryx was proclaimed. This discovery occurred just two years after Charles Darwin, an English naturalist, released his book On the Origin of Species (scientific literature). Hence, it was a significant event that provided credibility to the debate over evolution.
Over the years, ten body fossil specimens of Archaeopteryx and a feather that may belong to it have been found. All of the fossils come from the limestone (sedimentary rocks) deposits, quarried for centuries, near, Germany. The initial discovery, a single feather, was unearthed in 1860 and described a year later by Christian Erich Hermann von Meyer, a German scientist. The Berlin museum possesses this best known specimen to this day. Full specimens were discovered about every 20 years after that. The first full specimen, known as the "Berlin specimen," was discovered in Germany in 1876. The first skeleton, known as the London Specimen was discovered in 1861 near Germany, and given to a local physician Karl Haberlein in return for medical services. He then sold it to the Natural History Museum in London, where it remains.
In contrast to all living modern birds, Archaeopteryx had a full set of teeth, a rather flat sternum ("breastbone"), a long, bony tail, gastralia ("belly ribs"), and three claws on the wing which could have still been used to grasp prey (or maybe trees). However, its feathers, wings, furcula ("wishbone") and reduced fingers are all distinctiveness of modern birds. Archaeopteryx had the ability to run and glide, allowing it to escape from predators more rapidly, and progressively longer gliding eventually evolved into full-fledged flight. Archaeopteryx certainly had feathers, although whether these feathers were used for regulating its body temperature or for flight is a matter still open for debate. Feathers may have originally developed for insulation and then been co-opted into flight. Two models of the evolution of flight have been proposed:
Archaeopteryx may have 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. As far as their diet is concerned, Archaeopteryx was carnivorous birds that fed on small animals and insects.
Even though archaeopteryx had well-developed flight feathers and other bird-like features, it is not sure if Archaeopteryx was just a glider or could fly long distances. Absence of a bony breastbone did not make this archaic a strong flier. On the other hand, strong flight muscles could have been attached to its well developed, boomerang shaped wishbone. The shoulder joint is more dorsally positioned in the modern bird which facilitates them to lift their wings above their body for the upstroke required for flapping flight. However, the shoulder joint in these prehistoric birds had a more sideways orientation that did not permit them to lift their wings high. Therefore, this arrangement did not provide for upstroke of the wings as in modern birds. However, Archaeopteryx wings were capable of executing down stroke which allowed them to at least glide, if not fly freely like present day birds.