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Mustersan

Wikipedia contributorsAdapted for Fathomly · View authors
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Source updated June 7, 2026

The Mustersan age is a period of geologic time (circa 38-35 Ma) within the Eocene epoch of the Paleogene, used more specifically within the South American land mammal age (SALMA) classification. It follows the Casamayoran and precedes the Divisaderan or Tinguirirican ages.

01Etymology

This age is named after Lake Musters in the Golfo San Jorge Basin.

02Formations

Formation
bold is type		 Country Basin Notes
Sarmiento Formation ArgentinaGolfo San Jorge Basin
Abanico Formation ChileAbanico Basin
Andesitas Huancache Formation ArgentinaGolfo San Jorge Basin
Chota Formation PeruBagua Basin
Geste Formation ArgentinaPuna Plateau
Paracas Formation PeruPisco Basin
Pozo Formation PeruUcayali Basin
Soncco Formation PeruEastern Peruvian Andes
Vaca Mahuida Formation ArgentinaNeuquén Basin
Ventana Formation ArgentinaNeuquén Basin
Yahuarango Formation - Santa Rosa fauna PeruUcayali Basin

03Fossils

Group Fossils Formation Notes
MammalsAntepithecus brachystephanus, Guilielmoscottia plicifera, Kramadolops mayoi, Propyrotherium saxeum, Pseudhyrax eutrachytheroides, Eomorphippus sp.Sarmiento
Chlorocyon phantasma, Ignigena minisculus, aff. Ernestokokenia sp., Borhyaenidae indet., Oldfieldthomasiidae indet.Abanico
Archaeopithecus cf. rogeri, Asmithwoodwardia subtrigona, Bardalestes hunco, Gashternia ctalehor, Greniodon sylvaticus, Henricosbornia lophodonta, Homalostylops parvus, Palangania cf. brandmayri, Polydolops rothi, P. unicus, Prostegotherium cf. astrifer, Amphidolops sp., Marmosopsis sp., Notostylops sp., Pauladelphys sp., Protodidelphis sp., Riostegotherium sp., Stegosimpsonia sp., Borhyaeninae indet., Caroloameghiniinae indet., Hathlyacininae indet.Andesitas
Huancache
Antofagastia turneri, Bonapartherium serrensis, Parastegosimpsonia cf. peruana, Parutaetus punaensis, Prostegotherium notostylopianum, Pucatherium parvum, Punadolops alonsoi, Punahyrax bondesioi, Punapithecus minor, Punatherium catamarquensis, Reigia punae, Suniodon catamarcensis, Astegotherium sp., Callistoe sp., Colbertia sp., cf. Ernestokokenia sp., cf. Pampahippus sp., Propyrotherium sp., cf. Utaetus sp., Astrapotheriidae indet., Interatheriidae indet., Isotemnidae indet., Litopterna indet., Notohippidae indet., Notostylopidae indet., Notoungulata indet., Oldfieldthomasiidae indet., Typotheria indet.Geste
Eobranisamys riverai, E. romeropittmanae, Eodelphomys almeidacomposi, Eoespina woodi, Eoincamys ameghinoi, E. pascuali, Eopicure kraglievichi, Eopululo wigmorei, Eosachacui lavocati, Eosallamys paulacoutoi, E. simpsoni, Hondonadia pittmanae, Incadolops ucayali, Kirutherium paititiensis, Kiruwamaq chisu, Micoureus laventicus, Parastegosimpsonia peruana, Patene campbelli, Perulestes cardichi, P. fraileyi, Perupithecus ucayaliensis, Rumiodon inti, Sasawatsu mahaynaq, Wamradolops tsullodon, Wirunodon chanku, Yuruatherium tropicalis, Guiomys sp., Scleromys sp., Sipalocyon sp., cf. Microsteiromys sp., Acaremyidae indet., Chiroptera indet., ?Gondwanatheria indet., Glyptodontinae indet., Hystricognatha indet., Interatheriinae indet., cf. Notohippidae indet.Yahuarango
BirdsPerudyptes devriesiParacas
Psilopteridae indet.Sarmiento
Presbyornithidae indet.Vaca
Mahuida
Reptiles &
amphibians		Boidae indet., Sebecidae indet., Testudines indet.Geste
Shelania laurentiVaca
Mahuida
Boinae indet.Sarmiento
InsectsAcanthocephalonotum martinsnetoi, Archimyrmex piatnitzkyi, A. smekali, Madres delpueblo, ?Atalophlebia sp., Stratiomyidae indet.Ventana
FloraAgathis zamunerae, Atherospermophyllum guinazui, Embothrium precoccineum, ?Embothrium pregrandiflorum, Fagus subferruginea, Lomatia preferruginea, Retrophyllum spiralifolium, Blechnum sp.Ventana
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Sources and credits

This article is adapted from the Wikipedia article “Mustersan”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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Lake Musters

Lake Musters is located in the central Patagonian region of the Argentina, south of the province of Chubut, and together with Lake Colhué Huapi, it forms the terminal phase of the current endorheic basin of the Senguerr River. Both lakes are located in the Valle de Sarmiento.