the only Late Cretaceous nodosaurid from North America. Panoplosaurinae was then revived in 1986 by Paul Sereno, who used it to unite Panoplosaurus, Sauropelta, Silvisaurus and Struthiosaurus within Nodosauridae, excluding Hylaeosaurus and Polacanthus. Robert Bakker then redescribed specimens from the Late Cretaceous of North America in 1988, prompting him to separate Edmontonia rugosidens into the new subgenus Chassternbergia, remove a specimen from Edmontonia longiceps making it the new genus Denversaurus, and identify a former specimen of Panoplosaurus mirus as P. sp.. To distinguish the Panoplosaurus species from the Edmontonia complex, Bakker placed Panoplosaurus in Panoplosaurinae, and Edmontonia, Chassternbergia and Denversaurus in Edmontoniinae, uniting the two subfamilies into the family Edmontoniidae, which he placed in Nodosauroidea, the family Nodosauridae of Coombs' use elevated to superfamily rank. Carpenter further reviewed Late Cretaceous North American nodosaurids in 1990, concluding that Bakker's justification for separation was lacking; placing Chassternbergia and Denversaurus as junior synonyms of Edmontonia, and only narrowing down the classification of Panoplosaurus and Edmontonia to Nodosauridae. In 1998, Sereno modified his earlier position, using the name Nodosaurinae for the group of derived nodosaurids including Panoplosaurus, and informally defining the subfamily as all taxa closer to Panoplosaurus than Sarcolestes or Hylaeosaurus. Tracy Ford published a novel classification of Panoplosaurus in 2000, using osteoderm anatomy to divide Nodosauridae into Nodosaurinae including only Nodosaurus, Sauropeltinae including Sauropelta and Silvisaurus, Edmontoniinae including Edmontonia and a distinct Chassternbergia, and Panoplosaurinae including only Panoplosaurus. The first phylogenetic analysis to include Panoplosaurus was that of Yuong-Nam Lee in 1996, where Panoplosaurus mirus, including both CMN 2759 and ROM 1215 nested next to Edmontonia, which included both E. longiceps and E. rugosidens, to the exclusion of all other nodosaurids. A similar union of Panoplosaurus and Edmontonia was recovered in 1998 by Jim Kirkland and colleagues, but the 2001 analysis of Carpenter instead recovered Edmontonia closest to Animantarx, while Panoplosaurus nested next to a clade of Sauropelta and Silvisaurus. The 2003 analysis of Robert Hill and colleagues resolved a group of Edmontonia and Animantarx, with Panoplosaurus as the sister taxon, and the analysis of Matthew Vickaryous et al. recovered Panoplosaurus and Edmontonia as sisters, though Animantarx was not analysed. Expansions on the analysis of Vickaryous and colleagues resolved the same clade of Panoplosaurus and Edmontonia with the additions of the nodosaurid Hungarosaurus, the ankylosaurid Crichtonsaurus benxiensis, the nodosaurid Struthiosaurus, and the supposed ankylosaurid Tatankacephalus. The next novel analysis was that of