2016年在吉林省延吉市南部龙山和西部太阳河白垩系龙井组地层中，发现大量恐龙类、鳄形类和龟鳖类骨骼化石。目前龙山剖面发现5个化石层，累计厚约10.6 m，其中第3和第5化石层稳定、连续，其它三层呈透镜状断续分布，间隔分布于河流相沉积序列中。根据区域测年数据推测龙山化石地层年龄为距今100—91 Ma，结合化石和地层对比，确定化石地层属于晚白垩世最早期。

In 2016, abundant dinosaurian, crocodiliform and testudine fossils were recovered in the southern part of Longshan and western part of the Sun River in Yanji, Jilin Province. Five fossil-bearing layers have been discovered in Longshan locality, with a total thickness of about 10.6 m. The third and fifth fossil-bearing layers are stable and continuous, while the other three layers are discontinuous, with limited distribution in the deposits. Based on the comparative paleontological and radiometric dating data, it is inferred that the age of the Longshan fossil stratum is 100—91 Ma age, and thus the fossil-bearing beds were formed in the earliest Late Cretaceous.

国家自然科学基金基础科学中心项目（批准号：41688103）和中国科学院战略性先导科技专项（B类）(编号：XDB18030504)资助。