Patagomaia is an extinct mammal of uncertain affinities, originally described as a therian mammal, from the Maastrichtian Chorrillo Formation of Argentina. It is the largest Mesozoic mammal yet known, with weight estimates of around . The genus contains a single species, Patagomaia chainko, known from various fragmentary bones.
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Patagomaia is an extinct mammal of uncertain affinities, originally described as a therian mammal, from the Maastrichtian Chorrillo Formation of Argentina. It is the largest Mesozoic mammal yet known, with weight estimates of around . The genus contains a single species, Patagomaia chainko, known from various fragmentary bones.
==Description== Patagomaia chainko was described in 2024 based on two specimens, the holotype specimen, MPM-PV-23365, comprising 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, and a referred specimen, MPM-PV-23366, comprising a partial left acetabulum and ischium and part of the right femoral shaft. In 2025, Chimento et al. described an additional specimen, MPM-PV-23515, originating from the same site at which the holotype was found, likely belonging to that same individual. It includes a partial thoracic and caudal vertebra and 38 indeterminate bone pieces.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).