Palaeoscincus costatus Leidy, 1856

Figure 9C, D

Palaeoscincus costatus Leidy is based on a single tooth and is the only ankylosaur species to have been reported from the Judith River Formation until the present study. The tooth was figured by Leidy (1860, pl. 9, figs. 49-52). AMNH 8542 from the present collection is similar to Leidy's specimen. AMNH 8542 has large and sometimes distinct denticles with well-separated cones (fig. 9C, D).

The flutings, however, do not extend to the base of the crown. A basal cingulum is present on the lingual side.