Archaeopteryx

Archaeopteryx is an early type of bird that is transitional between feathered dinosaurs and modern birds. It lived in the Late Jurassic Period of Europe.

Description
The largest known specimens of Archaeopteryx grew to a length of about half a meter, with an estimated weight of about a kilogram. Most specimens come from the Solnhofen limestone in Bavaria, Germany, which dates to about 150 million years ago.

Archaeopteryx has both bird and dinosaur features. Like birds, it has a wishbone, wings, and feathers. But unlike birds and like theropod dinosaurs, it has teeth and a long bony tail. Many scientists, such as Thomas Huxley and John Ostrom, have used this combination of features as evidence that birds and dinosaurs are related.

Researchers have at least partially determined the color of Archaeopteryx's feathers. By examining the shape of preserved melanosomes of the original feather fossil (a similar procedure to how the colors of Sinosauropteryx and Anchiornis were determined), they found that the feather was probably black.

Classification
Archaeopteryx was long thought to be the earliest bird, but recent evidence in the form of genuine dinosaurs that possessed the same features has revised its classification to a feathered dinosaur.

Classification between species is even more confusing. Currently all the specimens are contained within a single species, A. lithographica. But most of the specimens were differently classified at their discovery, and were given names such as Archaeornis, Jurapteryx, and Wellnhoferia. These distinctions can be considered valid, as many skeletons exhibit noticeable differences. However, these could just be morphological changes in relation to age.

The placing of Archaeopteryx into one species has left behind a plethora of synonyms which numbers well over two dozen.

History
The initial discovery of Archaeopteryx was a single feather, which was described in 1861 by Christian Erich Hermann von Meyer. Whether this feather actually belonged to Archaeopteryx is debated today.

The first skeleton was uncovered the same year, known as "the London specimen". It was given to a doctor, who sold it to the Natural History Museum in London. It was described by Richard Owen in 1863, who recognized it as an ancient bird. Charles Darwin even mentioned it in the 4th edition of his book On the Origin of Species.

Nine specimens were discovered in later years. The most famous of which, "the Berlin specimen", was discovered around 1875 by a farmer. He sold the fossil to buy a cow. It was sold again and again throughout the next few years, being passed on from one to another in exchange for money, potential buyers including the American fossil hunter Othniel Charles Marsh. It was eventually bought by the Humboldt Museum für Naturkunde, where it remains today. The Berlin specimen is the most complete example, and is one of the most famous fossils to this day.

In 2011, the eleventh specimen was announced. As it rests in private hands, it has yet to be described, but it is one of the more complete specimens.

Diet
Many suggest that Archaeopteryx fed on small prey both on the ground and in trees.

Flight
The lack of a breastbone suggests that Archaeopteryx was not a strong flier. Although it is uncertain whether it could achieve powered flight, it was probably able to glide.