The phylogenetic and biostratigraphic significance of new armadillos (Mammalia, Xenarthra, Dasypodidae, Euphractinae) from the Tinguirirican (early oligocene) of Chile

Synopsis

Two new species of early Oligocene dasypodids are described from the Tinguiririca Fauna of Chile, the basis of the recently formalised Tinguirirican South American Land Mammal ‘Age’. Specimens recovered to date, all referable to the Euphractinae, include articulated portions of the movable bands and pelvic shield, an unassociated partial mandible and skull, and isolated osteoderms. Ornamentation of the osteoderms (i.e. the shape of the central figure and keel and the arrangement of the peripheral figures) indicates that these taxa represent early diverging members of the subfamily. Cranial remains from Chile somewhat resemble Sadypus Ameghino (?early Oligocene), particularly in their long, low rostra. One of the new species from Tinguiririca also occurs in Eo‐Oligocene faunas from Patagonia (Argentina) currently under study, providing a basis for long distance biochronological correlation. The material from Tinguiririca assumes special importance given that most Eocene and Oligocene dasypodids are known exclusively from isolated osteoderms. The unusally complete material from Tinguiririca thus provides important phylogenetic insights by clarifying the morphology of the cingulate exoskeleton during a key interval in the clade's diversification.

Key words:

• basal Euphractinae
• Parutaetus
• Meteutatus
• Tinguirirican
• Palaeogene
• South America

Notes

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