# Riochican

The Riochican (Spanish: Riochiquense) age is a period of geologic time (57.0–54.0 Ma) within the Paleocene and Eocene epochs of the Paleogene, used more specifically within the South American land mammal ages (SALMA). It follows the Peligran and precedes the Itaboraian age.

## Etymology

This age is named after the Río Chico Group of the Golfo San Jorge Basin.

## Formations

| Formation bold is type | Country | Basin |
| Río Chico Group | Argentina | Golfo San Jorge Basin |
| Bogotá Formation | Colombia | Altiplano Cundiboyacense |
| Bororó Formation | Argentina | Golfo San Jorge Basin |
| Chota Formation | Peru | Bagua Basin |
| Koluel Kaike Formation | Argentina | Golfo San Jorge Basin |
| Las Flores Formation | Argentina | Austral Basin |
| Maíz Gordo Formation | Argentina | Salta Basin |
| Mealla Formation | Argentina | Salta Basin |
| Mogollón Formation | Peru | Talara & Tumbes Basins |
| Muñani Formation | Peru | Altiplano Basin |
| Peñas Coloradas Formation | Argentina | Golfo San Jorge Basin |
| Río Loro Formation | Argentina | Sierras Pampeanas |
| Salamanca Formation | Argentina | Golfo San Jorge Basin |

## Fossils

| Group | Fossils | Formation | Notes |
| Mammals | Etayoa bacatensis | Bogotá | |
| Mammals | Brandmayria simpsoni, Ernestokokenia chaishoer, E. ?yirunhor, Isotemnus cf. primitivus, Palangania brandmayri, Anisolambda sp., Henricosbornia sp., Josepholeidya sp., Notopithecus sp., Othnielmarshia sp., Polydolops winecage, Ricardolydekkeria sp., Trigonostylops sp., Victorlemoinea sp., ?Eohyrax sp., ?Nemolestes sp., ?Notostylops sp., ?Pleurostylodon sp., ?Polystylops sp., ?Postpithecus sp., Dasypodidae indet. | Koluel Kaike | [16][17] [18] |
| Mammals | Eoastrapostylops riolorense, Notonychops powelli, Satshatemnus bonapartei | Río Loro | |
| Reptiles & amphibians | Testudines indet. | Koluel Kaike | |
| Reptiles & amphibians | Pelomedusoides sp. | Maíz Gordo | |
| Reptiles & amphibians | Lorosuchus nodosus, Pelomedusoides cf. argentinensis | Río Loro | |
| Fishes | ?Cyprinodon primulus | Maíz Gordo | |
| Insects | Anthicus sepultulus, Austrolibellula noroestenia, Carabites harringtoni, Celinapterix bellissima, Cryptophagus sunchalensis, Curculionites harringtoni, C. jujuyensis, C. magdalinus, C. parastictus, C. stebingeri, C. sunchalicus, C. wielandi, Curviarculia delicata, C. lamasi, Gryllites vocalis, Jujusia maizgorda, Latibasalia elongata, L. quispeae, Lebia harrelli, Ormenis devincta, Otiorhynchites aterrimus, O. crassus, Palaeomacromia multicellulata, Palaeophya argentina, Promegalestes singularis, Tenebrionites inclinans, Thyridates novokschonovi, ?Anthonomus sunchalensis, ?Corizus deflagratus, ?Cossonus devoratus, ?Haruspex defectus, ?Molanna derosa, ?Podabrus santaritensis, ?Trichodes stebingeri | Maíz Gordo | [22][23] [24][25] [26][27] [28][29] |
| Flora | Banaraphyllum ovatum, Cissites patagonica, Cryptocaryoides mariasantisimensis, Dryophyllum australis, Fagophyllum duseni, Laurophyllum chubutensis, Laurophyllum piatnitzkyi, Myrica premira, Nothofagidites visserensis, Paranymphaea aristolochiaformis, Sterculia acuminataloba, Zizyphus chubutensis | Río Chico | |
| Flora | Palmoxylon patagonicum | Bororó | |
| Flora | Cordioxylon prototrichotoma | Peñas Coloradas | |
| Flora | Palmoxylon patagonicum | Salamanca | |