In a comment on the initial Shunosaurus tail-club post, Jaime Headden pointed out the passage in the Spinophorosaurus paper (Remes et al. 2009) that discusses the club of Shunosaurus (as justification for positioning the Spinophorosaurus osteoderms on the end of its tail): And this gives the reference that I needed for the Shunosaurus tail-spikes (as opposed to the club) — reference 26 is Zhang