The single autapomorphy of Stokesosaurus is found on the ilium on both specimens. Yes, I did say yesterday that there was only one recognized specimen, however, there is a supposedly juvenile ilium that is attributed to Stokesosaurus. Both ilia are marked with a ridge from the superior to the inferior edge of the ilium. That ridge angles posteriorly along the surface. Highlighted line drawings of the specimens make that ridge look like an upside down Y embossed on the outer surface. The anatomy as inferred by many different researchers is considered to be heavily tyrannosaur influenced though the basal body plan was probably a lot more gracile and agile than the later and more advanced larger tyrannosaurs.