AVIMIMUS (AYV-ee-MIME-us)

Period: Late Cretaceous

Order, Suborder, Family: Saurischia, Theropoda, Avimimidae

Location: Asia (Mongolia)

Length: 5 feet (1.5 meters)

Avimimus ("bird mimic") was a small, lightly built theropod from the Upper Cretaceous Djadokhta Formation of Mongolia. The original specimens were collected by Soviet scientists, and several partial skeletons and skulls have since been found. The most complete skeleton is a partial skull, vertebrae from the neck and back regions, an incomplete arm, most of both back legs and feet, and part of the pelvis.

The skull was short and birdlike; it was toothless and had a beak and a long neck. The bones that surrounded and protected the brain were large, showing it may have had a large brain. The hole in the back of the skull where the spinal cord was, called the foramen magnum, is very large for a dinosaur of this size. But the occipital condyle (the bump of bone on the back of the skull that connects the skull to the neck vertebrae) is very small, showing the skull was light for its size.

The ulna (the largest of the two forearm bones) had a ridge similar to rows of bumps on the ulna of modern birds. These bumps are where the quills of large flight feathers attach. Seriozha Kurzanov claimed that this is evidence that Avimimus had feathers. The original skeleton was missing a tail, which led Kurzanov to speculate that Avimimus did not have a tail. Since then, however, tail vertebrae have been found with other fossils. The back legs of Avimimus were long in relation to its thigh bones, showing it was a fast runner. Kurzanov believes that the many birdlike features in the skull and arm of Avimimus show it was capable of weak flight. This would have made it a feathered, flying theropod dinosaur that developed separately from true birds. Most paleontologists, however, do not agree.

Kurzanov thinks this animal fed mainly on insects. Others have suggested it was herbivorous. More information is needed to determine the exact nature of this unusual dinosaur, its habits, and its relationship to other dinosaurs.