Caudipteryx, meaning “tail feather”, is a genus of small theropod dinosaur that lived during the Aptian Age of the Early Cretaceous Period (124 million years ago). There are two species known, C. zoui (described 1998) and C. dongi. (described 2000). It was first discovered in 1997 in the Yixian Formation of the Sihetun area of Liaoning Province, northeastern China. The genus appears to have been fairly common, though isolated to the small region where it has been found. This region was also home to other feathered dinosaurs Dilong and Sinornithosaurus.
This dinosaur, like other maniraptorans, had an interesting mix of reptile/bird -like anatomical features. It had a short boxy skull with a beak-like snout. It had only a few tapered teeth in the front of the upper jaw. The trunk was stout and the long legs indicate it may have been a quick runner. It had a short tail that was stiffened at the tip with only a few vertebrae, like in modern birds. The pelvis and shoulder were primitive, as was the skull. It had a hand skeleton with a reduced third finger, like that of primitive birds. The teeth were bird-like. It had other features that are comparable to modern flightless birds.
The hands of Caudipteryx bore feathers that had vanes and barbs. These feathers measured 6 to 8 inches long. The primary feathers of the hands were arranged in a wing-like fan pattern along the second finger, just like in birds of today. No secondary feathers have been preserved in any of the remains of Caudipteryx. Either those secondary feathers were not preserved, or were not present in life. A fan of feathers also existed on its short tail. The shortness of the feathers both on the arms and tail, and relative to its body size, indicate that Caudipteryx could not achieve flight. The body was covered in a simple coat of downy feathers.
Caudipteryx is believed to be an omnivore. This assumption is based on stones and pebbles found in the remains of the skeleton where the gizzard would have been. These stones were most likely used to help the animal grind, digest and process food matter.