Xiaosaurus

Millions of years ago, Asia was home to various dinosaurs. The population of dinosaurs in this area was a mix of giant plant eaters and predators. The Xiaosaurus (pronounced as “chow-saw-rus”) was one of the most prominent herbivores on this continent. This ornithischian dinosaur lived about 169–163 million years ago during the Middle Jurassic Period. Scientists have discovered fossils of the Xiaosaurus in places like Sichuan in China.

Description and Size

Xiaosaurus is a genus of ornithischian (bird-hipped) dinosaur that lived during the Jurassic in an area that is now present-day China. One of the most interesting facts about this dinosaur is that it was one of the first dinosaurs whose name begins with the letter “X.” 

The name, Xiaosaurus, translates as “dawn lizard.” It is from the Chinese word “Xiao,” which means “dawn.” Scientists assigned this name to the dinosaur because the fossil is ancient. The Xiaosaurus was one of the oldest dinosaur fossils found in this part of the world. However, since it dates back to the Middle Jurassic, it would have been more accurately called a “noon lizard,” considering the dawn of the dinosaur age was in the Late Triassic. 

Xiaosaurus was a small bipedal dinosaur. This means it walked on two legs even though it had four limbs. The front limbs were too short to be used for walking. However, the hind limbs were long and muscular. The femur of the rear foot was about 4.3 inches long, while the dinosaur had an estimated length of 3-4 ft (1-2 m) and weighed roughly 15 lb (7 kg). It was also about 3.3 ft (1 m) tall.

Xiaosaurus is a typical ornithopod which means it had bird-like hips, and its body had a lizard-like length. Dinosaurs in this group typically had beaked mouths with leaf-shaped cheek teeth. Since they were herbivorous, they did not have sharp claws or teeth.

Standing at about 4 feet (1.2 meters), this dinosaur was not a giant. It was smaller than a human adult. Each of the hindlimbs of the Xiaosaurus had four toes, while the arms had five fingers. The dinosaur had a long, pointed tail and a flexible neck. It was also characterized by a small head with huge eyes. 

Diet — What Did Xiaosaurus Eat?

Scientists believe that the dawn lizard had an entirely herbivorous diet. It isn’t exactly clear the types of plants that this dinosaur ate, but since they were so small, they probably fed predominantly on low-lying plants and foliage from small trees in the area. 

Habitat — When and Where Xiaosaurus Lived

Xiaosaurus is of Asian Origin. It lived in a place now known as China. The dinosaur lived in a terrestrial habitat in the Sichuan Basin. This is a large intracratonic basin located in the southwestern region of China. The most prominent formation in this basin is the Shaximiao Formation. This formation is made up of fluvial-lacustrine deposits that date back to the Middle Jurassic when the Xiaosaurus lived there. The basin is known for its well-preserved vertebrate fossils, especially dinosaurs like the Xiaosaurus. 

Threats and Predators

The Xiaosaurus was a small-sized herbivorous dinosaur. This means it would have been easy prey for any large carnivorous dinosaurs that lived in the same habitat at the time. Famous carnivorous dinosaurs like the Velociraptor lived in ancient China. However, they came along during the Late Cretaceous when the Xiaosaurus was all gone. Other relatively large predatory dinosaur species that preyed on Xiaosaurus would have also existed at the time.

Discoveries and Fossils — Where It Was Found

Paleontologists uncovered two specimens that they considered small, herbivorous dinosaurs in 1979 and 1980. The two specimens were from excavations near Dashanpu in the Sichuan area of China, a part of the Sichuan Basin. 

The find consists of partial remains, which included jaw fragments with a single tooth, four caudal vertebrae, two cervical vertebrae, humorous, and a partial left femur. A complete right hindlimb was also found. Scientists Dong Zhiming and Tang Zilu assigned a name to the two fossils in 1983. The name “dawn lizard” is a reference to the age of the dinosaurs. 

Extinction — When Did Xiaosaurus Die Out?

Xiaosaurus lived for a relatively short time (169–163 million years ago) during the Middle Jurassic Period. The reasons for the dinosaur’s extinction aren’t clearly known. However, since they were herbivores, environmental changes might have affected their plant food source, leading to their eventual disappearance. 

Similar Animals to the Xiaosaurus

Similar dinosaurs to the Xiaosaurus include: 

• Nanosaurus — Also known as “dwarf lizard,” Nanosaurus lived in North America during the late Jurassic, about 155 to 148 million years ago. It is around the same size as the Xiaosaurus.
• Dilong – The emperor dinosaur is a distant relative of the Tyrannosaurus rex. It lived during the late Cretaceous (126 million years ago) in the western Liaoning province of China. 
• Shantungosaurus: This dinosaur lived in China during the Late Cretaceous. It is one of the largest dinosaur fossils discovered on the Asian Continent. 

Related Animals 

• Sinosauropteryx
• Brachiosaurus
• Cryolophosaurus

1. Kidadl, Available here: https://kidadl.com/facts/dinosaurs/xiaosaurus-facts
2. Wikipedia, Available here: https://en.wikipedia.org/wiki/Xiaosaurus
3. Dinosaur Pictures, Available here: https://dinosaurpictures.org/Xiaosaurus-pictures