Compsognathus dinosaur is known from two almost complete skeletons, one from Germany that is 90 cm long, and one more from France that is 125 cm; other skeletons point to a size range from 70-140 cm. Teeth from Portugal have also been assigned to the genus. Although the French specimen was initially described as a separate species (Compsognathus corallestris), both it and the German specimen are now thought to be Compsognathus longipes. A fractional foot has also been referred to Compsognathus, but this has subsequently been disproved.
Compsognathus may have had only two fingers, since no bones of a third finger have been established. However, the hands are disarticulated, so this is still unsure. It appears that Compsognathus preyed on small vertebrates, since leftovers of the lizard Bavariasaurus have been found in its thoracic cavity. For many years, Compsognathus was the only well known small theropod, and was thus compared to Archaeopteryx as a dinosaurian ancestor or family member of birds. It is now known that many other kinds of dinosaurs were more closely related to birds, including Segnosaurus, Oviraptorosaurus and Deinonychosaurus. It is often argued that Compsognathus lacked feathers, because none are preserved with moreover skeleton, while Archaeopteryx, which was found in the same sediments, always preserves feathers. However, the only feathers always potted on Archaeopteryx are the large ones on the wings and tail.
Compsognathus was discovered by Dr.Oberndorfer and its skeleton was found in the Natural History Museum, London.The short feathers which cover the body are rarely potted. A relative of Compsognathus, Sinosauropteryx, only has short feathers, so it is likely Compsognathus was feathered too.