The remains of one of the world's smallest dinosaurs - measuring just 4in tall - have been discovered.
The fossil bones come from a newly-identified creature that weighed less than 900g (2lb) and was about 60cm (2ft) long from head to tail.
Luis Chiappe, director of the Dinosaur Institute of the Natural History Museum of Los Angeles County, described the creature as looking like "a roadrunner on steroids".
It is thought likely to have eaten plants and hunted insects during the late Jurassic period, about 150 million years ago.
The dinosaur was so tiny and fast that it probably darted between the legs of larger dinosaurs, researchers said.
Bones of four individuals - including skull, arm and leg fragments - were discovered three decades ago in Fruita in western Colorado and kept at the museum.
But Chiappe and an international team have only now identified and named it Fruitadens haagarorum, which incorporates where the bones were found and the name of the president of the museum's board of trustees, Paul Haaga.
A description of their work appears Wednesday in the British journal Proceedings of the Royal Society B: Biological Sciences.
The creature is said to be the smallest dinosaur discovered in North America.