When the armored dinosaur Liaoningosaurus paradoxus was first described in 2001, it didn’t make much of a splash in the popular or paleontological press. The original specimen represented a very small animal, only about 34 cm in total length. That specimen preserved some unusual features for an ankylosaur, including two very large plates of bone covering nearly the entire belly, and very few spikes or other bits of bony armor on the back. This is unlike most ankylosaurs which generally have extensive coverings of osteoderms (the bony cores of spikes, plates, and scale-like scutes that grow within the skin) on their backs and sides. The overall small size of the specimen and the lack of fusion between parts of the vertebrae led most paleontologists to regard the specimen as an indeterminate juvenile.
In August of 2016 however, a new specimen of Liaoningosaurus was described, also from the Lower Cretaceous Yixian Formation in Liaoning Province, northeastern China. Like the original specimen, this new specimen was extremely small, lacked fusion within vertebrae or the sacrum, and seemed to lack dorsal scutes.
Incredibly, this specimen appears to preserve evidence that Liaoningosaurus ate fish. Preserved within the ribcage are incomplete portions of fish skeletons. The authors consider it unlikely that the ankylosaur died on top of the fish carcasses and they ended up within the ribcage and there are no other fish skeletons found near the specimen. Additionally, they find it unlikely that the fish died within the skeleton while scavenging as there does not appear to be any indication that the skeleton was scavenged before burial. In fact, the fragmentary and incomplete nature of the fish skeletons seem to point toward their being gut contents.