Yongchuanosaurus was a large carnivorous dinosaur that lived during the Late Jurassic period, named after Yongchuan County in Chongqing where its specimens were first discovered. It had a nearly 1-meter-long, slightly triangular head with six pairs of large openings on each side, effectively reducing head weight. One pair of these openings were eye openings, indicating excellent vision; the others were attached to powerful muscle groups for tearing and chewing. Yongchuanosaurus's mouth was filled with rows of sharp teeth, like daggers, and its short, thick neck gave it tremendous bite force. Its long tail served as a balancer while running. Its forelimbs were highly flexible, with curved, sharp claws on its fingers, allowing it to firmly grasp prey. Its hind limbs were long and robust, with three toes, allowing it to walk on three toes like modern wading birds (birds adapted to living in swamps and near water), enabling it to run very quickly. With such hind limbs, the Yongchuanosaurus could catch its prey with ease.
As a large carnivorous animal, *Yongchuanosaurus* often roamed jungles and lakeshores, and its behavior was likely similar to that of modern tigers and leopards. It was aloof and preferred to hunt alone. Some gentle herbivorous dinosaurs were often its prey, and once targeted, escape was difficult. Therefore, these herbivorous dinosaurs were always vigilant, and would flee at top speed at the slightest disturbance or upon smelling the scent of *Yongchuanosaurus*.
The Yongchuanosaurus has a rich fossil record. Besides the relatively complete fossil individuals discovered in Yongchuan in the 1970s, a remarkably complete skeletal fossil unearthed in 1985 was identified as a new species of the genus *Yongchuanosaurus* and named *Heping Yongchuanosaurus*. It had a large, heavy head with dagger-like sharp teeth; short forelimbs and long hind limbs, walking on two legs with large, sharp claws. It lived in the highland thickets along river and lake shores, preying on herbivorous dinosaurs and other animals, and was an exceptionally ferocious carnivorous dinosaur. This specimen, approximately 9 meters long, is currently the most complete carnivorous dinosaur found in Asia. In December 1986, farmers in Chanluo Village, Chadian Township, discovered many strangely shaped stones in the rock wall behind their house while quarrying for repairs. After identification, it was determined to be a dinosaur fossil group. Although the exposed parts had been damaged, the parts buried within the rock wall remained intact. However, due to insufficient funding, the excavation work was forced to stop, and the secrets hidden within await future discovery.
Chinese name: Yongchuan Dragon
Latin name: Yangchuanosaurus
Age of existence: Late Jurassic
Fossil origin: Chongqing, China
Physical characteristics: 10-11 meters in length
Diet: Carnivorous
Type: Theropod
Meaning: Lizard from Yongchuan
