The Compsognathidae is a group of small, lightly-built coelurosaurs with relatively long legs and tails. They have three-fingered hands. The genera contains only three members.
   Compsognathus was for many years the smallest known dinosaur.  It was a bird-like dinosaur that walked on two long, thin legs; it had three-toed feet. A long tail acted as a counterbalance and for stability during fast turns. It had short arms with two clawed fingers on each hand. Compsognathus had a small, pointed head with small, sharp teeth, hollow bones, and a long, flexible neck. was 28 inches long and weighted about 6.5 pounds, about the size of a house cat.  It lived in the late Jurassic period, about 155 to 145 million years ago. 
   Compsognathus was discovered by Dr. Oberndorfer in limestone deposits in the Riedenburg-Kelheim region of Bavaria, southern Germany in the late 1850's. It was named by Johann A. Wagner in 1859. Only two Compsognathus fossils have been found; one in Germany and one in France.  The latter is on display at the Paleontological Museum. A lizard skeleton still remains in its abdominal cavity.
   Compsognathus is believed by many scientists to be an early elative of Archaeopteryx, often considered to be the first bird.  Supporting this belief is the fact that the bone structure of Compsognathus is quite similar to that of Archaeopteryx, and the two dinosaurs were about the same size. They also lived at the same time in history, which would have made it difficult for Compsognathus to be an ancestor. It is still possible, though, that Compsognathus lived earlier than Archaeopteryx. On the other side of the argument, Compsognathus had hollow bones, like modern birds, but Archaeopteryx had solid bones. Another objection is that Compsognathus doesn't have a collar bone, and many scientists believe birds' wishbones must have evolved from an animal with a collarbone. But while Compsognathus didn't have a collar bone, perhaps one of its relatives did.
    Compsognathus was the sole member of this genera until the discovery of Sinosauropteryx in 1990. This new discovery was remarkable in that it had feathers. A 3rd species was discovered in 2004.