The Malargüe Group is a group of geologic formations of the Neuquén Basin of the Mendoza, Neuquén, Río Negro and La Pampa Provinces in northern Patagonia, Argentina. The formations of the Malargüe Group range in age between the middle Campanian to Deseadan, an Oligocene age of the SALMA classification, straddling the Cretaceous–Paleogene boundary, about 79 million to 30 million years in age. The group overlies the older Neuquén Group, separated by an unconformity dated to 79 Ma. The rocks of the Malargüe Group comprise both marine and continental deposits which are over 400 m (1312 ft) thick in total.

The Malargüe Group is subdivided into:

• Agua de la Piedra Formation (Deseadan) - white-grayish tuffs and tobaceous paleosols
• Roca Formation (Maastrichtian to Danian) - coastal mudstones and sandstones
• Jagüel Formation (middle Maastrichtian to Danian) - shallow marine mudstones
• Loncoche Formation (late Campanian to early Maastrichtian) - terrestrial conglomerates and sandstones, delta plain sandstones and limestones
• Allen Formation (middle Campanian to early Maastrichtian) - eolian sandstones and fluvio-lacustrine mudstones and limestones

Fossils of dinosaurs, plesiosaurs, turtles (Euclastes, Mendozachelys wichmanni), Paleoanculosa sp., fish, birds (cf. Andrewsornis sp.) and mammals have been recovered from the strata that make up the Malargüe Group.

Mammals of the Agua de la Piedra Formation

Archaeohyrax suniensis, Argyrohyrax proavus, Asmodeus petrasnerus, Fieratherium sorex, Gualta cuyana, Hegetotheriopsis sulcatus, Mendozahippus fierensis, Meteutatus aff. lagenaformis, Proborhyaena gigantea, Prohegetotherium malalhuense, P. schiaffinoi, P. cf. sculptum, Propachyrucos cf. smithwoodwardi, ?Prozaedyus aff. impressus, Pyrotherium romeroi, Stenotatus aff. ornatus, Trachytherus cf. spegazzinianus, cf. Archaeotypotherium sp., Pharsophorus sp., Proadinotherium sp., Progaleopithecus sp., cf. Prosotherium sp., Acaremyidae indet., Glyptodontidae indet., Interatheriidae indet., Litopterna indet., ?Megalonychidae indet., Notohippidae indet., Toxodontidae indet.

• List of fossil sites
• Santa Lucía Formation, Maastrichtian to Danian (Tiupampan) fossiliferous formation of the Potosí Basin, Bolivia
• Yacoraite Formation, Maastrichtian to Danian fossiliferous formation of the Salta Basin
• Lopez de Bertodano Formation, Maastrichtian to Danian fossiliferous formation of northern Antarctica

Cretaceous

• De la Fuente, M.S.; Maniel, I.; Janello, J.M.; Sterli, J.; Riga, B.G.; Novas, F. (2017), "A new large panchelid turtle (Pleurodira) from the Loncoche Formation (upper Campanian-lower Maastrichtian) of the Mendoza Province (Argentina): Morphological, osteohistological studies, and a preliminary phylogenetic analysis" (PDF), Cretaceous Research, 69: 147–168, doi:10.1016/j.cretres.2016.09.007, retrieved 2019-02-21
• González Riga, B.J (1999), "Hallazgo de vertebrados fósiles en la Formación Loncoche, Cretácico Superior de la provincia de Mendoza, Argentina", Ameghiniana, 36: 401–410
• Leanza, H.A.; Apesteguia, S.; Novas, F.E.; De la Fuente, M.S. (2004), "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages", Cretaceous Research, 25: 61–87, Bibcode:2004CrRes..25...61L, doi:10.1016/j.cretres.2003.10.005, retrieved 2019-02-16
• Previtera, E.; González Riga, B.J. (2008), "Vertebrados cretácicos de la Formación Loncoche en Calmu-Co, Mendoza, Argentina (Cretaceous vertebrates from the Loncoche Formation in Calmu-Co, Mendoza, Argentina)", Ameghiniana, 45: 349–359, retrieved 2019-02-21
• Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (2004), The Dinosauria, 2nd edition, Berkeley: University of California Press, pp. 1–880, ISBN 0-520-24209-2, retrieved 2019-02-21

Paleogene

• Cerdeño, Esperanza; Reguero, Marcelo (2015), "The Hegetotheriidae (Mammalia, Notoungulata) assemblage from the late Oligocene of Mendoza, central-western Argentina", Journal of Vertebrate Paleontology, 35 (2): e907173, Bibcode:2015JVPal..35E7173C, doi:10.1080/02724634.2014.907173, hdl:11336/48566, retrieved 2015-02-13
• Cerdeño, Esperanza; Vera, Bárbara (2014), "A new Leontiniidae (Notoungulata) from the Late Oligocene beds of Mendoza Province, Argentina", Journal of Systematic Palaeontology, 13 (11): 943–962, doi:10.1080/14772019.2014.982727, hdl:11336/59428, retrieved 2019-02-12
• Combina, Ana María; Nullo, Francisco (2011), "Ciclos tectónicos, volcánicos y sedimentarios del Cenozoico del sur de Mendoza-Argentina (35-37° S y 69° 30'W)" (PDF), Andean Geology, 38: 198–218, retrieved 2018-09-11
• Hernández Del Pino, Santiago; Seoane, Federico D.; Cerdeño, Esperanza (2017), "New postcranial remains of large toxodontian notoungulates from the late Oligocene of Mendoza, Argentina and their systematic implications" (PDF), Acta Palaeontologica Polonica, 62: 195–210, retrieved 2019-02-12
• Seoane, Federico; Cerdeño, Esperanza (2014), "First extra-Patagonian record of Asmodeus Ameghino (Notoungulata, Homalodotheriidae) in the Late Oligocene of Mendoza Province, Argentina", Ameghiniana, 51 (5): 373–384, doi:10.5710/AMGH.07.07.2014.2735, retrieved 2019-02-12