Its fossils have been found in the Hunter Wash and De-na-zin members of the Kirtland Formation of Upper Cretaceous (Campanian) New Mexico.

The genus is named after the Zia sun symbol, a stylized sun with four groups of rays, having religious significance to the Zia people of New Mexico, and the iconic symbol on the state flag of New Mexico, and pelta (Latin), a small shield, in reference to the osteoderms found on all ankylosaurids.

Z. sanjuanensis was identified as a new species from a number of fossils including the holotype NMMNH P-64484 found from the De-na-zin Member and consisting of a complete skull lacking the lower jaws, parts of the first two cervical half-rings, and a number of partial osteoderms; and a referred specimen NMMNH P-66930 from the older Hunter Wash Member, consisting of a first cervical half-ring.

By argon dating of ash layers the age of the holotype skull has been determined at between 72.98 and 72.62 million years old, the late Campanian.

[1] In 2014 Victoria Megan Arbour, Michael Burns, Robert Sullivan, Spencer Lucas, Amanda Cantrell, Joshua Fry and Thomas Suazo named the type species Ziapelta sanjuanensis.

The caputegulae are more irregular in form, at best lightly convex instead of cone-shaped, have a more rectangular outline, instead of a rounded one, and are separated by deeper grooves.

[1] The skull has no constriction in front of the eye sockets and its widest point is formed by the squamosal horns on the top rear corners.

The antorbital portion of the skull was lightly convex, and the premaxillae were broad and square, and covered in a rather flat cranial ornamentation.

Behind this central plate rows of smaller caputegulae run backwards; they have a diameter of about three centimetres each and are rectangular, pentagonal or hexagonal.

[1] At the underside of the skull, the paired front praemaxillae form a bony secondary palate, with a concave surface.

Where the middle segments touched each other on the midline, an irregular punctuated row of small trapezium-shaped "interstitial" osteoderms was present within the suture.

A third, measuring 118 by 68 millimetres, had a narrow keel and the shark fin shape typical of the ankylosaurian side spikes and was thus identified as a lateral rump osteoderm.

Some small ossicles were discovered also, round scutes of between two and four centimetres in cross-section, with a conical or flat shape and featuring a pitted surface.

[1] Ziapelta was placed in the Ankylosauridae, as possibly closely related to Scolosaurus from Canada, being its sister species in several of the evolutionary trees rendered by the cladistic analysis that was part of the describing paper.

However, the authors indicated that an alternative tree in which Ziapelta and Nodocephalosaurus were forced to be sister species was just one evolutionary step longer, i.e. requiring the presence of but a single additional shared trait, and thus only slightly less likely.

[1] The following cladogram is based on a 2015 phylogenetic analysis of Ankylosaurinae conducted by Arbour and Currie:[4] Crichtonpelta Tsagantegia Zhejiangosaurus Pinacosaurus Saichania Tarchia Zaraapelta Dyoplosaurus Talarurus Nodocephalosaurus Ankylosaurus Anodontosaurus Euoplocephalus Scolosaurus Ziapelta Since, Ziapelta and other Late Cretaceous North American ankylosaurids are grouped with Asian genera, in a tribe which the authors dubbed Ankylosaurini, Arbour and Currie suggested that earlier North American ankylosaurids had gone extinct by the late Albian or Cenomanian ages of the Middle Cretaceous.