The Santacrucian armadillos Peltephilus (Mammalia, Dasypodidae, Peltep
hilinae) are reanalysed in order to test the traditional hypothesis th
at they were the most cursorial and active hunters of the dasypodids.
The masticatory musculature is reconstructed, the form and distributio
n of teeth are studied, and a model of the jaw movements is proposed.
Furthermore, the limb anatomy as well as their index of fossorial foss
orial ability are compared with those of other armadillos. It is concl
uded that Peltephilus, and very Likely other peltephilines, are poorly
designed as carnivorous, actively cursorial mammals. An alternative h
abit is proposed, in which Peltephilus and the other peltephilines are
viewed as having the conservative armadillo structure of diggers, fee
ding on soft but tough items, probably plant material of underground o
rigin.