A possible juvenile ceratopsoid ilium from the Cenomanian of central Utah, U.S.A.

We describe a small ilium, with fibrous texture characteristic of juvenile bone, from the lower Cenomanian of central Utah, U.S.A. The ilium was recovered from the upper part of the Mussentuchit Member of the Cedar Mountain Formation. The ilium most closely resembles that of immature ceratopsid ilia referred to Agujaceratops mariscalensis from the Campanian Aguja Formation of southern Texas, U.S.A. Both have everted dorsal margins over the iliac body, subhorizontal postacetabular processes, and laterally compressed, anteroventrally curved preacetabular processes. If correctly identified, the small ilium from the Cedar Mountain Formation is the oldest ceratopsid or ceratopsoid known, and shows that the diversity of early ceratopsians was greater than previously realized.