Considered to be the first bird, Archaeopteryx is one of the most important animals ever discovered. With a wingspan of less than 2 feet, it was not very big. It's diet probably consisted of insects and perhaps the occasional small reptile or mammal. Only a handful of fossils have been found, but the ones that are known show this bird in extraordinary detail. Recently, it's status as a bird has been questioned by some and the future of it's placement in the dinosaur family tree is in doubt. Archaeopteryx lived about 150 million years ago in Europe.