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Divisaderan

South American land mammal age

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Source updated June 7, 2026

The Divisaderan age is a South American land mammal age, covering a period of geologic time within the Middle or Late Eocene epochs of the Paleogene (>36.0 Ma). It follows the Mustersan age and is followed by the Tinguirirican age.

The Divisaderan is named after the Divisadero Largo Formation of Divisadero Largo, Mendoza, Argentina. It was originally distinguished by an unusual combination of archaic mammals and more recent-looking notoungulate fossils. However, more recent studies argue that the distinctive notoungulates reported from the Divisadero Largo Formation may actually be sourced from the younger (Miocene-age) Mariño Formation. Without these fossils, the Divisaderan may be too poorly-distinguished to stay in use compared to other middle-late Eocene SALMAs.

01Formations

Formation bold is type	Country	Basin
Divisadero Largo Formation	Argentina	Cuyo Basin
Abanico Formation	Chile	Abanico Basin
Andesitas Huancache Formation	Argentina	Golfo San Jorge Basin
Chota Formation	Peru	Bagua Basin
Guabirotuba Formation	Brazil	Curitiba Basin
Leticia Formation	Argentina	Austral Basin
Loreto Formation	Chile	Magallanes Basin
Paracas Group	Peru	Pisco Basin
Pozo Formation	Peru	Ucayali Basin
Sarmiento Formation	Argentina	Golfo San Jorge Basin
Soncco Formation	Peru	Eastern Peruvian Andes
Yumaque Formation	Peru	Pisco Basin

02Fossils

Group	Fossils	Formation
Mammals	Acamana ambiguus, Adiantoides leali, Allalmeia atalaensis, Brachystephanus postremus, Groeberia minoprioi, G. pattersoni, Phoradiadius divortiensis, Xenostephanus chiottii, Trigonostylops sp., ?Notoungulata indet.	Divisadero Largo
	Proeocoleophorus carlinii, Machlydotherium sp., Meteutatus sp., Nemolestes sp., Parutaetus sp., Utaetus sp., Argyrolagoidea indet., Astegotheriini indet., Astrapotheria indet., Euphractinae indet., Notopithecidae indet., Oldfieldthomasiidae indet., Palaeothentoidea indet.	Guabirotuba
	Ocucajea picklingi, Supayacetus muizoni, Basilosauridae indet.	Paracas
	Cachiyacuy contamanensis, C. kummeli, Canaanimys maquiensis, Eobranisamys javierpradoi, Eocoleophorus glyptodontoides, Pozomys ucayaliensis, Pseudostegotherium chubutanum, cf. Eoespina sp., cf. Griphodon sp., cf. Perulestes sp., Rumiodon sp., Sasawatsu sp., Stegosimpsonia sp., ?Trigonostylops sp., Wamradolops sp., Archaeohyracidae indet., Bonapartherioidea indet., Borhyaenidae indet., Chinchilloidea indet., Cingulata indet., Didelphimorphia indet., Interatheriinae indet., Litopterna indet., Microchiroptera indet., Molossidae indet., Phyllostomatidae indet., Polydolopimorphia indet., ?Sudamericidae indet., Toxodontia indet.	Pozo
	Pseudocladosictis determinabile, Patene coluapiensis, Angelocabrerus daptes, Arminiheringia auceta, Caroloameghinia mater, C. tenuis, Coona gaudryi, Rosendolops primigenium, Polydolops crassus, P. serra, P. thomasi, Amphidolops serrula, Eudolops tetragonus, Pseudolops princeps, Progarzonia notostylopense, Ideodelphys microscopicus, Tonostylops spissus, Thomashuxleya rostrata, Coelostylodon caroloameghinoi, C. florentinoameghinoi, Acoelohyrax complicatissimus, Isotemnus colhuehuapiensis, I. primitivus, Anisotemnus distentus, Pleurostylodon crassiramis, P. modicus, P. similis, Homalostylops parvus, Notostylops bicinctus, N. murinus, Isostylops fretus, Catastylops deflexus, Eohyrax isotemnoides, E. praerusticus, Archaeopithecus fossulatus, A. rogeri, Maxschlosseria consumata, Oldfieldthomasia debilitata, O. parvidens, O. transversa, Ultrapithecus rutilans, Paginula parca, Transpithecus obtentus, Antepithecus brachystephanus, A. innexus, Notopithecus adapinus, Henricosbornia ?lophodonta, Acoelodus proclivus, Proectocion argentinus, P. precisus, Didolodus magnus, D. minor, D. multicuspis, Paulogervaisia inusta, P. mamma, P. porca, Ernestokokenia nitida, Albertogaudrya unica, ?Trigonostylops duplex, T. wortmani, Parutaetus chicoensis, P. clusus, P. signatus, Meteutatus percarinatus, Pseudostegotherium chubutanum, Prostegotherium astrifer, P. notostylopianum, Utaetus buccatus, U. deustus, U. lenis, Machlydotherium sparsum, Rutimeyeria conulifera Guilielmofloweria plicata, Anisolambda fissidens, Proplanodus adnepos, Periphragnis exauctus, Mazzoniphractus ingens	Sarmiento
	Mystacodon selenensis	Yumaque
Reptiles & amphibians	Cunampaia simplex, Ilchunaia parva, Barinasuchus sp.	Divisadero Largo
	?Balanerodus sp., cf. Sebecus sp., Anilioidea indet., Anura indet., Booidea indet., Caimaninae indet., ?Chelidae indet., Gavialoidea indet., Pipidae indet., ?Platynota indet.	Pozo
	Eocaiman cavernensis, ?Boa sp., ?Madtsoia sp., Crocodylomorpha indet.	Sarmiento
Birds	Spheniscidae indet.	Loreto
Fishes	Ischyodus dolloi, Striatolamia macrota, Elasmobranchii indet.	Loreto
Fishes	Potamotrygon ucayalensis, ?Colossoma sp., cf. Leporinus sp., cf. Hydrolycus sp., Actinopterygii indet., Characiformes indet.	Pozo
Flora	Chara (Grambastichara) tornata, Nitellopsis (Tectochara) latispira	Pozo

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Sources and credits

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