Zuul crurivastator was named by Arbour and Evans (2017) [Differs from all ankylosaurids in the possession of the following autapomorphies: imbricated, peaked frontonasal and frontoparietal caputegulae; prominent longitudinal furrows on the lateral surface of the squamosal horn; lateral caudal osteoderms along the tail club (excluding the knob osteoderms) are strongly concave on the leading edge with posteriorly offset apices; tail club knob dorsoventrally flat, with height to length ratio less than 0.20. Zuul can be further differentiated from other ankylosaurins in the following traits: possesses pyramidal prefrontal, frontoparietal and middle supraorbital caputegulae (unlike the conical caputegulae in Nodocephalosaurus and Talarurus); squamosal horns extend posteriorly well past the nuchal shelf, similar to Scolosaurus but unlike Anodontosaurus, Euoplocephalus, or Ziapelta; postocular caputegulae small and sparsely distributed, similar to Scolosaurus but unlike Anodontosaurus, Euoplocephalus or Ziapelta. Caudal osteoderms lateral to tail club handle are proportionately larger and more sharply pointed than in ankylosaurines from the Nemegt Formation of Mongolia.]. Its type specimen is ROM 75860, a partial skeleton, and it is a 3D body fossil. Its type locality is Theropoda Exp LLC Locality LC02(Q), which is in a Campanian terrestrial horizon in the Judith River Formation of Montana.