The Solimoes Formation is a geologic formation located in the states of Acre and Amazonas in northwest Brazil. It preserves many fossils dating to the Miocene epoch of the Neogene period.
Description The Solimoes Formation is situated in the Acre Basin, a sedimentary basin formed by Andean tectonic events that occurred along the west margin of South America in the Neogene. It is traditionally dated to the Late Miocene by biostratigraphy and zircon geochronology. The formation is mostly consists of mudstones, siltstones and muddy sandstones, deposited under fluvio-lacustrine settings.
Paleofauna A diverse fauna of vertebrates have been discovered from the Solimoes Formation. The following vertebrates have been discovered. https://www.scielo.br/j/aabc/a/3QxzHLsNN3pWMMF6G3LGXVP/?lang=en
Mammalia
Primates Taxon Species Location Stratigraphic position Material Notes ImagesAcrecebusA. fraileyi Rio Acre, Patos and Cachoeria do Bandeira A cebid monkeySolimoeaS. acrensis Rio Acre, Patos and Cachoeria do Bandeira An ateline monkeycf. Stirtonia (mammal) https://www.researchgate.net/publication/7247296_New_platyrrhine_monkeys_from_the_Solimoes_Formation_late_Miocene_Acre_State_BrazilS. sp. An ateline monkeyParabrachytelesP. vesperus An ateline monkeyMigmacebus.https://link.springer.com/article/10.1007/s10914-026-09829-zM. juruaensis A cebid monkey
Marsupials Taxon Species Location Stratigraphic position Material Notes ImagesDidelphisD. solimoensisAn early opossumLutreolinaL. materdei A lutrine opossum
Rodents Taxon Species Location Stratigraphic position Material Notes ImagesEumegamysE. paranensisFerigolomysF. pacarana Neoepiblema N. horridulaNeoreomysN. huilensis A caviomorph rodentPhoberomysP. burmeistriA giant rodent.PotamarchusP. adamiaeA dinomyid rodentP. murinusPseudopotamarchusP. villanuevaiScleromysS. colombianus A dinomyid rodentTelicomysT. amazonensisCaviodonC. spCardiatheriumC. spTetrastylusT. spEoincamysE. spEobranisamysE. spDrytomomysD. sp
Notoungulates Taxon Species Location Stratigraphic position Material Notes ImagesAbothrodonA. pricei A haplodontheriidaeGyrinodonG. quassusA toxodontHaplodontheriumH. wildei A haplodontheriidaeMesenodonM. juruaenisisA toxodontMesotoxodonM. pricei A haplodontheriidaeMinitoxodonM. acrensisA toxodontNeotrigodonN. utoquineae A haplodontheriidaeNeotoxodonN. pascualiA toxodontPlesiotoxodonP. amazonensisA toxodontPurperiaP. cribatidens A LeontiniidToxodonT. sp A toxodontTrigodonT. spA large horned toxodont.TrigodonopsT. lopesi A haplodontheriidae
Astrapotheres Taxon Species Location Stratigraphic position Material Notes ImagesXenastrapotheriumX. amazonense A astrapothere Xenarthrans Taxon Species Location Stratigraphic position Material Notes ImagesKraglievichiaK. carinatum A pampatheriid armadillo MionothropusM. cartellei A nothrotheriid ground slothPseudoprepotheriumP. venezualemA ground sloth.OctodontobradysO. puruensis A mylodontid ground slothUrumacotheriumU. campbelli A mylodontid ground slothMegatheriumM. sp A megatheriid ground slothHapalopsH. indifferens A megatherioidea ground slothAnadasypus https://www.researchgate.net/publication/389278580_Dasypodidae_Mammalia_Cingulata_from_the_AC-64_outcropBR_364_Solimoes_formation_Late_Miocene_Acre_BrazilA. sp A dasypodini armadilloBoreostemmaB. sp A glyptodont armadilloPlohophorusP. sp A glyptodont armadilloPliomorphus P. sp A megalonychidae ground slothcf. ProtomegalonyxP. sp A megalonychidae ground slothcf. PlanopsP. sp A planopsinae ground sloth
Reptilia Taxon Species Location Stratigraphic position Material Notes ImagesPurussaurusP. brasiliensisA giant caiman. ChelusC. colombianusA mata mataGryposuchusG. jesseiA large gavialoid.MourasuchusM. amazonensisA large flat-snouted caiman.Melanosuchus M. latrubessei C. aff. crocodilusEunectesE. spA prehistoric anaconda.StupendemysS. souzaiA giant podocnemidid side-necked turtleAcresuchusP. pachytemporalisCaimanC. brevirostrisC. aff. crocodilus
Aves Taxon Species Location Stratigraphic position Material Notes ImagesAnhingaA. fraileyiA. grandisA. minutaPhorusrhacidae indet.IndeterminateA large indeterminate phorusrhacid.MacranhingaM. ranziiA large relative of the Anahinga.
Fish Taxon Species Location Stratigraphic position Material Notes Images
References