One specimen of Liaoningosaurus was retrieved from the Jiufotang Formation of the Jehol Group. It overlies the Yixian Formation, and is composed of mudstones, siltstones, shales, sandstones and tuffs. Similar to the Yixian Formation, it represents a lacustrine environment lacking rivers and deltas. The Jiufotang Formation experienced less volcanism compared to its underlying formation, and fluctuated seasonally between semi-arid and mesic conditions. Based on analyses using secondary ion mass spectrometry (SIMS) zircon U-Pb, the formation dates to the late Barremian and Aptian stages of the Lower Cretaceous period, approximately 122.0–118.9 Ma. Zhou et al. (2022) suggested that the Jehol ecosystem (the Yixian and Jiufotang Formations) may have been more suitable for the survival of juvenile ankylosaurs based on the lack of adult specimens and abundance of juvenile specimens. The Jiufotang Formation has yielded specimens of the basal ankylosaurid Chuanqilong, the ceratopsian Psittacosaurus, the dromaeosaurid Microraptor, the oviraptorosaur Similicaudipteryx, the jeholornithiforms Jeholornis and Kompsornis, and the tyrannosaur Sinotyrannus. Other vertebrate fossils found in the formation included fish, mammaliamorphs such as Fossiomanus and Liaoconodon, the choristoderans Philydrosaurus and Ikechosaurus, pterosaurs like Liaoningopterus, Sinopterus, and Guidraco, enantiornithines such as Longipteryx, Sinornis and Yuanchuavis, and a variety of early birds like Yanornis and Yixianornis. See also Halszkaraptor Koreaceratops Lurdusaurus Spinosaurus Timeline of ankylosaur research References Ankylosaurids Aptian life Early Cretaceous dinosaurs of Asia Cretaceous China Fossils of China Yixian fauna Fossil taxa described in 2001 Taxa named by Xu Xing Ornithischian genera