Richard Thompson and colleagues in 2012, combining previous ankylosaurian analyses into a single one to analyse both Nodosauridae and Ankylosauridae. Panoplosaurus was resolved next to Edmontonia, deep within an unresolved polytomy of all nodosaurids more derived than Animantarx, which included Niobrarasaurus, Nodosaurus, Pawpawsaurus, Sauropelta, Silvisaurus, Stegopelta, and Texasetes. In 2016, the phylogenetic analysis of Arbour and Currie initially meant to test the relationships of Ankylosauridae was expanded to include many of the nodosaurids known at the time, with Panoplosaurus limited to the holotype due to a lack of consensus about referred specimens. Following further modifications and expansions, Panoplosaurus was continually found within a group including Edmontonia and also at times Animantarx, Texasetes, Denversaurus (if considered separate from Edmontonia) and an unnamed ankylosaur from Argentina. As a result of this consistent support, Daniel Madzia and colleagues decided to name the clade uniting all taxa closer to Panoplosaurus than Nodosaurus or Struthiosaurus, giving it the formal name Panoplosaurini, modifying the suffix -inae from previous uses as it was continually nested within the clade Nodosaurinae. The reference phylogeny for Panoplosaurini designated by Madzia and colleagues was that of Rivera-Sylva et al. (2018), which is a modified version of the Arbour and Currie analysis expanded to include the Mexican taxon Acantholipan. Their results can be seen below. Paleobiology Feeding Ankylosaurs were traditionally viewed as having a generic method of feeding due to their simple teeth, stiff skulls, and unspecialized musculature, comparable to modern iguanids. However, unlike iguanids ankylosaurs frequently have significant tooth wear, sometimes all the way down to the base of the crown. Nodosaurids normally have oblique wear facets on teeth, in Panoplosaurus having a single wear facet per tooth which changes angulation across the tooth row, going from sub-vertical at the snout to nearly horizontal at the back of the mouth. This differs from ankylosaurids, but may be due to the alignment of teeth between the upper and lower jaws, instead of a difference in form of mastication. While the shape of teeth in Panoplosaurus and other ankylosaurs suggests a simple, soft food diet, their variability implies a less restrictive feeding strategy. Nodosaurid teeth are more blade-shaped than those of ankylosaurids, a possible evolutionary response to a tougher, fibrous diet. However, microwear on the teeth of ankylosaurids and Panoplosaurus instead show that their diets were not significantly different, with regular pitting and abrasion showing a diet consisting occasionally of fruit as well