Genus: Hoplitosaurus LUCAS, 1902
Etymology: Greek, hoplites, “armed foot-soldier, shield (hoplon) carrier” and Greek, sauros, “lizard”: “Shield-carrier lizard”.
= Holitosaurus CARPENTER & KIRKLAND, 1998 (sic)

Species: marshi (LUCAS, 1901) LUCAS, 1902
Etymology:
= Stegosaurus marshi LUCAS, 1901
= Polacanthus marshi (LUCAS, 1901) PEREDA-SUBERBIOLA, 1991

Holotype: USNM 4752

Locality: Calico Canyon, Buffalo Gap, sec. 2, T7S, R5E, Custer County (Fall River County, OSTROM, 1965), South Dakota.

Horizon: Lakota Formation.

Biostratigraphy:

Age: Barremian Stage, Lower Neocomian Subepoch, Middle Early Cretaceous Epoch, Early Cretaceous.

Material: Right femur, half of left humerus, distal half of right humerus, proximal portion of right scapula and coracoid, 1 dorsal centrum, caudal centra, numerous dermal plates of spined, keeled, flattened and rounded shapeless, fragments of ribs and other elements.