[3] Its strange, almost toothless and elongated skull indicates a specialization for myrmecophagy, the eating of ants, unique among the order Cingulata, which includes pampatheres, glyptodonts and all the extant species of armadillos.

[4] Stegotherium tessellatum was described originally in 1887 by Florentino Ameghino based on the remains of a carapace collected by his brother Carlos in the Santa Cruz Province of Argentina.

[6] In 1904, after the discovery of additional remains of S. variegatum, William Berryman Scott re-evaluated Scaetops simplex as a species of Stegotherium different from S.

The teeth were cylindricals and greatly reduced, both in number and in size, and were all contained in the posterior area of the lower and upper jaws.

[8] The body of Stegotherium was roughly the size of the modern species of Dasypus,[5][8] and its carapace was composed of at least 23 mobile bands of osteoderms.

It had quadrangular osteoderms, with a single large foramen in the exterior margin, devoid of longitudinal ridge of any kind in the central region.

Its only diagnosis characteristic could be the presence of two molariform teeth on the mandible, while S. tessellatum had six;[10] the validity of the species has been debated since 1902,[8][1][4] and the holotype is probably lost.

The species is mainly known from fossilized quadrangular osteoderms, whose exposed surface showed several piliferous pits around a single granulated central figure, and a longitudinal ridge surrounded, in all of its length, by depressions.

[This paragraph needs citation(s)] The specific name, caroloameghinoi, is meant to honour Carlos Ameghino, who discovered the holotype of Stegotherium and was a prominent figure in the history of paleontology in Patagonia.

Some of the non-osteoderm material used by González Ruiz and Scillato-Yané to describe S. tauberi was assigned by Fernicola and Vizcaíno to S. tessellatum; both species are, however, considered valid by the current consensus.

[This paragraph needs citation(s)] Its species name, tauberi, honours Adán Alejo Tauber, an Argentinian paleontologist who worked on the Santa Cruz Formation.

[7] It lived alongside a diversity of related cingulates, such as the Euphractine Prozaedyus, the basal Chlamyphorid Proeutatus, the Dasypodid Stenotatus, the horned armadillo Peltephilus and several genera of glyptodonts, such as Asterostemma, Propalaehoplophorus, Cochlops and Eucinepeltus.

[7] After the Santacrucian, the genus is only known by one Colloncuran fossilized osteoderm, MLP 91-IV-1-66 from the Collón Curá Formation, tentatively assigned to Stegotherium sp.