Limb reconstruction of Eutatus seguini (Mammalia: Xenarthra: Dasypodidae). Paleobiological implications

Eutatus seguini Gervais is one of the largest members of the family Dasypodidae. It was very common during the Late Pliocene-Early Holocene in Uruguay and central-eastern Argentina. Some specimens that include well preserved and complete endoskeletal elements allowed to perform morpho-functional and biomechanical studies in order to infer locomotory adaptations. Comparative anatomical descriptions of Eutatus seguini Gervais with the recent armadillos Chaetophractus villosus (Desmarest), Dasypus hybridus (Desmarest), And the only living species of similar size Priodontes maximus (Kerr), were made. Its body mass was estimated through allometric equations. Different indices were calculated in order to analyse its limb proportions and their correlation with digging habits. The indices were compared with the values recorded for all living armadillo tribes, from mostly cursorial through subterranean. The general architecture and proportions of the limbs of E. seguini, and therefore its digging habits, are similar to those of the Euphractini and Dasypodini. Eutatus seguini shows unique features, for it reaches the size of the hiperspecialised digger and mirmecophagous Priodontes maximus, but with less fossorial specialisation and markedly herbivorous feeding habits.