ANATOMY Xiaosaurus was a small, lightly-built dinosaur. It was an herbivore (a plant-eater) and a fast, agile runner. It was small and lizard-like, about 5 feet (1.5 m) long. It walked on two long legs, had four-toed feet, five-fingered hands, short arms, a long, stiff, pointed tail, a flexible neck, and a small head with large eyes. It had leaf-shaped cheek teeth. Xiaosaurus lived during the middle Jurassic period, about 169-163 million years ago. Xiaosaurus was an herbivore (plant-eater) that ate low-lying plants.