The caudal vertebrae of Jinchuanloong niedu in northwestern China. Jinchuanloong niedu, however, is helping to fill in those missing pieces. Despite its preservation, the first known Jinchuanloong niedu specimen doesn’t appear to be an adult. Physiological features including unfused neural arches in the caudal vertebrae imply that the dinosaur was a juvenile or subadult when it died. But given that it was already nearly 100 feet long, it’s a near-certainty that Jinchuanloong niedu still grew to colossal proportions.