and the Origin of Birds
of the most important paleontological finds came in 1861, with the
discovery of Archaeopteryx in Late Jurassic (around
146 million years ago) limestones near Solnhofen, Germany. Although
the skeleton of Archaeopteryx was nearly identical to that
of the small theropod dinosaur Compsognathus,
this fossil also bore the unmistakable imprints of feathers. For over
100 years, Archaeopteryx was the strongest evidence that
birds had evolved from
and it therefore deserved a place on the dinosaur family tree. Since
then, many other feathered dinosaurs have been found
in China, further supporting this hypothesis, and future discoveries
will help us understand exactly how flight evolved in this unique
group of theropods.
Although the first bird represents a remarkable evolutionary event,
the Jurassic skies truly belonged to another group of vertebrates,
the pterosaurs. These flying reptiles, relatives of
the dinosaurs, had evolved in the Triassic but by now were very diverse.
Pterosaurs lived on nearly every continent and were far more common
than birds throughout the Jurassic. They came in many shapes and sizes:
long-tailed forms such as Rhamphorhynchus, huge-headed Dimorphodon,
and the sparrow-sized and short-tailed Pterodactylus.