The Mayoan (Spanish: Mayoense) age is a period of geologic time from 11.8 to 10 Ma, within the Middle to Late Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Laventan and precedes the Chasicoan age.[1]


The age is named after the Río Mayo Formation in the Golfo San Jorge Basin of Patagonia, Argentina.


Locations of Mayoan formations
bold is type
Country Basin Notes
Río Mayo Formation  Argentina Golfo San Jorge Basin
Coquimbo Formation  Chile Tongoy Bay
Gran Bajo del Gualicho Formation  Argentina Colorado Basin
Huaylas Formation  Chile Parinacota Province
Mauri Formation  Bolivia Altiplano Basin
Navidad Formation  Chile Chilean Coast Range
Paraná Formation  Argentina Paraná Basin
Pebas Formation  Brazil
Amazon Basin
Pisco Formation  Peru Pisco Basin
Puerto Madryn Formation  Argentina Valdés Basin
Urumaco Formation  Venezuela Falcón Basin
Yecua Formation  Bolivia Paraná Basin

Fossil content

Group Fossils Formation Notes
Mammals Megathericulus patagonicus Río Mayo
Caraguatypotherium munozi, Epipeltephilus caraguensis Huaylas
Brujadelphis ankylorostris Pisco
Cardiatherium patagonicum, Kawas benegasorum, Notoziphius bruneti, Scirrotherium carinatum, Lagostomus (Lagostomopsis) sp., Dolichotinae indet., Macraucheniidae indet., Mylodontinae indet., Neuryurini indet., Palaehoplophorini indet. Puerto
cf. Theosodon sp. Yecua
Birds Kuntur cardenasi, Ramphastosula aguirrei, Sula brandi, S. figueroae Pisco
Madrynornis mirandus, Palaeospheniscus bergi, Accipitridae indet., Dendrocygninae indet., Psilopteridae indet. Puerto
Reptiles Mourasuchus sp., Pleurodira indet. Yecua
Fishes Cosmopolitodus hastalis Coquimbo
Loricariidae indet., Percomorpha indet., Siluriformes indet. Puerto
cf. Ariidae indet., Teleostei indet. Yecua


  1. ^ Paleo Database: Mayoan
  2. ^ Ecosteguy et al., 2003
  3. ^ Le Roux et al., 2006, p.49
  4. ^ Reichler, 2010, p.181
  5. ^ García et al., 1999, p.251
  6. ^ Marshall & Sempere, 1991, p.636
  7. ^ Finger et al., 2007, p.13
  8. ^ Martín Pérez, 2013, p.51
  9. ^ Antoine et al., 2016, p.56
  10. ^ Wesselingh et al., 2006, p.304
  11. ^ Brand et al., 2011
  12. ^ Acosta Hospitaleche et al., 2007, p.301
  13. ^ Linares, 2004, p.16
  14. ^ Hernández et al., 2002, p.5
  15. ^ Arroyo Pedregoso at
  16. ^ Montoya Sanhueza et al., 2017
  17. ^ Caragua at
  18. ^ Lambert et al., 2017
  19. ^ a b c Rincón Chico at
  20. ^ a b La Pastosa at
  21. ^ Punta San Román at
  22. ^ Playa El Doradillo at
  23. ^ Yecua at
  24. ^ Stucchi et al., 2015a
  25. ^ Stucchi et al., 2015b
  26. ^ Puerto Madryn Autodromo at
  27. ^ Playa Villarino at
  28. ^ a b La Angostura, Margin of Piraí River at
  29. ^ Tongoy area Unit 4 at


Río Mayo Formation
Coquimbo Formation
Gran Bajo del Gualicho Formation
Huaylas Formation
Mauri Formation
Navidad Formation
Paraná Formation
Pebas Formation
Pisco Formation
Puerto Madryn Formation
Urumaco Formation
Yecua Formation