Zupaytheriumrex -

MPCN-PV-9876, an associated partial skeleton including a right dentary with m1–m3, a fragmentary maxilla with M2–M4, axis vertebra, and partial right femur.

We thank the Museo Carmen Funes for access to collections. zupaytheriumrex

Mammalia Linnaeus, 1758 Eutriconodonta Kermack, Mussett & Rigney, 1973 Gobiconodontidae Chow & Rich, 1984 Zupaytherium gen. nov. a fragmentary maxilla with M2–M4

Cerro Cóndor Norte, Río Negro Province, Argentina; Allen Formation (Campanian–Maastrichtian, ~75–68 Ma). 1758 Eutriconodonta Kermack

Zupaytherium rex demonstrates that large predatory mammals evolved independently in Gondwana near the end of the Cretaceous. The presence of a 50+ kg mammal in the Allen Formation suggests that terrestrial food webs were more complex than previously recognized, with mammals occupying the 30–60 kg predator niche typically filled by small abelisauroid theropods in other Gondwanan faunas.