Mamenchisaurus size varied on the species but the largest species was 35 meters long with a nearly 17 meter long neck. It was preyed on by Sinraptor. Like all sauropods, it ate plants. These dinosaurs are the largest animals in the region. It was the family of suropod as mamenchisauidae.
In the episode New Giants, it doesn't make a physical apperance, but it is said to be the Asian sauropod that fought a large theropod which, in this case, is Sinraptor.