Juvenile ankylosaur specimens are very rare. A new ankylosaur, Liaoningosau
rus paradoxus gen. et sp. nov., is described based on a beautifully preserv
ed juvenile ankylosaur specimen from the famous Yixian Formation of Liaonin
g, China. Liaoningosaurus has a large bony plate (somewhat shell-like) shie
lding the abdomen. This discovery represents the first record of such a str
ucture among, dinosaurs. Although it has a number of distinct features seen
in the family Ankylosauridae, a cladistic analysis placed Liaoningosaurus
in the sister-family Nodosauridae. The 'intermediate' status of this taxon
between the two ankylosaur families further supports the monophyly of Ankyl
osauria. This finding also documents the smallest known ankylosaur specimen
and first complete nodosaurid specimen from Asia.