Patagomaia chainko is known from the distal end of the left ulna, two fragments of the preacetabular wing of the left ilium, acetabular region of the left hemipelvis, fragment of the ischial blade, proximal end of the right femur; distal end of the left femur, proximal end of the left tibia, and other indeterminate bone fragments. It is estimated to weigh over 14 kilograms (31 lb), narrowly beating the previous Mesozoic mammal contender, Repenomamus giganticus.[1][2]
Classification
Patagomaia chainko is tentatively described as a therian mammal. However, it does not match any early Cenozoic South American therian group.[1]
Alongside Malagasy gondwanatheres like Adalatherium and Vintana and South American mesungulatid meridiolestidans, Patagomaia chainko provides evidence that Late Cretaceous Gondwanan mammal faunas tended to achieve larger sizes than their northern counterparts.[1]