A particularly important and still contentious
discovery is Archaeopteryx lithographica, found in the Jurassic
Solnhofen Limestone of southern Germany, which is marked by rare but exceptionally
well preserved fossils. Archaeopteryx is considered by many
to be the first bird, being of about 150 million years of age. It is actually
intermediate between the birds that we see flying around in our backyards
and the predatory dinosaurs like Deinonychus. In fact, one
skeleton of Archaeopteryx that had poorly preserved feathers
was originally described as a skeleton of a small bipedal dinosaur, Compsognathus.
A total of seven specimens of the bird are known at this time.
It has long been accepted that Archaeopteryx
was a transitional form between birds and reptiles, and that it is the
earliest known bird. Lately, scientists have realised that it bears even
more resemblance to its ancestors, the Maniraptora, than to modern birds;
providing a strong phylogenetic link between the two groups. It is one
of the most important fossils ever discovered.
Unlike all living 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
as it is thought that the animal had to gain height by climbing before
taking off ). However, its feathers, wings, furcula ("wishbone")
and reduced fingers are all characteristics of modern birds.
As you can see, 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 evolved for insulation and then been co-opted
Below is an artists impression of how the skeleton might
have looked with meat and feathers on it....!