Eurypoda was initially defined by Sereno (1998) as a node-based taxon and party to a node-stem triplet (with Stegosauria and Ankylosauria). The active definition is a first-order revision that uses species as specifiers (Stegosaurus stenops, Ankylosaurus magniventris). As the monophyly of Eurypoda has yet to be challenged, the inclusion of negative taxon qualifiers to exclude the members of other ornithischian clades does not appear to be warranted.