Compsognathus

COMPSOGNATHUS (KOMP-sog-NAY-thus)

Period: Late Jurassic

Order, Suborder, Family: Saurischia, Theropoda, Compsognathidae

Location: Europe (Germany, France)

Length: 2 feet (60 centimeters)

Not all meat-eating dinosaurs were the gigantic brutes we imagine. Some were small and delicate. Compsognathus was one of the smallest known dinosaurs. It was a turkey-size predator that lived near water. This little animal ran birdlike on its back legs, chasing lizards and small mammals and attacking its prey with small, two-fingered hands and toothy jaws. Perhaps Compsognathus dined on Archaeopteryx, the oldest known bird.

German paleontologist Andreas Wagner described the first Compsognathus in 1861. Its name means "elegant jaw." A physician named Oberndorfer found it in lithographic limestone in a valley near the town of Kelheim. As happens with many small fossil vertebrates, sedimentary rock had squashed it flat. Its bones were too thin-walled to avoid being crushed when it was being fossilized. But nature preserved almost its entire skeleton, from the large head to more than halfway up the long, slender tail. Wagner did not identify Compsognathus as a dinosaur, probably because it did not fit his image of dinosaurs as huge and lumbering.

Several years later, Thomas Henry Huxley used Compsognathus as an example in his theory that present-day birds descended from "birdlike reptiles." As scientists studied the skeletons of other theropods, such as Allosaurus and Ornithomimus, it became clear that Compsognathus was a smaller relative of those dinosaurs.

In 1881, Othniel Marsh noticed that Wagner's specimen had something in its stomach and thought it might be an embryo. Franz Nopcsa in 1903 argued that the object was far too large to be an embryo and concluded that it was the remains of a lizard, the animal's last meal. Seventy-five years later, paleontologist John Ostrom identified the lizard as Bavarisaurus.

Compsognathus longipes is rare in museum collections. There is only one other specimen besides Wagner's, a skeleton about 50 percent larger that was discovered in lithographic limestone near Canjuers, France. A group of French paleontologists reported on this skeleton in 1972. They thought it belonged to a different species. They named this new species Compsognathus corallestris. It had flippers instead of hands and somewhat different skeletal proportions. Ostrom, however, showed that the "flipper imprint" in the specimen did not belong to the animal. He also showed that the differences between the specimen sizes were probably because one was younger. He considers the French skeleton a fully grown adult, while the German one was younger. Scientists now think both animals belong to the single species Compsognathus longipes.

Ostrom's 1978 study indicates that Compsognathus probably had two-fingered hands. This surprised many paleontologists, because all other known theropods except tyrannosaurids had hands with three or more fingers. Not everyone agrees that Ostrom's interpretation is correct. Compsognathus is different enough to be classified as the only member of its family, Compsognathidae.