The Pebas Formation is a lithostratigraphic unit of Miocene age, found in western Amazonia. The formation extends over 1,000,000 square kilometres (390,000 sq mi), including parts of Brazil, Peru, Ecuador and Colombia.[1] It is interpreted as representing the deposits of a lake ("Lake Pebas") or series of lakes, formed within the foreland basin of the Andes mountain belt. It is known for its abundant fossil ostracods and molluscs and an unusually diverse group of crocodylians.[2]

Pebas Formation
Stratigraphic range: Early Aquitanian-Tortonian
(Colhuehuapian-Huayquerian)
~21–8 Ma
The Pebas Mega-Wetland (or Lake Pebas), on the western side of this map, corresponds to the Pebas Formation
UnderliesMarañón Formation
OverliesChambira Formation
Area1,000,000 km2 (390,000 sq mi)
Thickness~350–1,074 m (1,148–3,524 ft)
Lithology
PrimarySiltstone, mudstone
OtherCoal/lignite
Location
Coordinates7°24′S 75°00′W / 7.4°S 75.0°W / -7.4; -75.0
Approximate paleocoordinates8°24′S 70°36′W / 8.4°S 70.6°W / -8.4; -70.6
RegionAmazon Basin
Country Brazil
 Colombia
 Ecuador
 Peru
Type section
Named forPebas District

Fossil content

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Fish

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Taxa Species Locality Stratigraphic position Material Notes Images
Anostomidae Indeterminate
Hydrolycus[3] cf. H. sp.
Leporinus[3] L. sp.
Pristis[3] P. sp.
Potamotrygon[3] P. sp.

Insects

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Taxa Species Locality Stratigraphic position Material Notes Images
Macroteleia M. yaguarum A parasitoid wasp.
 
Sycorax S. peruensis Relatives of moth flies and sand flies.

Mammals

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Taxa Species Locality Stratigraphic position Material Notes Images
Dinomyidae D. sp. A hystricognath rodent.
Octodontoidea Indeterminate. A hystricognath rodent.
Neoepiblema[5] N. sp. A hystricognath rodent.
Pebanista P. yacuruna Rio Napo. A nearly complete skull. A platanistid river dolphin.
 
Pseudoprepotherium P. sp. Rio Napo A ground sloth.
Potamarchus P. sp A hystricognath rodent.
Parapropalaehoplophorus P. sp a glyptodont

Reptiles

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Taxa Species Locality Stratigraphic position Material Notes Images
Caiman C. wannlangstoni Locality IQ26 and IQ114 A well-preserved partial skull. An extinct caiman
 
Gavialoidea Indeterminate.
Gnatusuchus G. pebasensis Locality IQ114, IQ116, and IQ125 Upper A nearly complete skull. A clam eating caiman.
 
Gryposuchus G. pachakamue Locality IQ101 A gavialid crocodilian.
 
Kuttanacaiman K. iquitosensis Locality IQ26 and IQ116 Middle nearly complete skull and mandibles. A small caiman.
 
Chelus C. colombianus Pieces of shell bones and scutes A slightly larger species of mata mata, reaching an estimated shell length of up to a meter.
Mourasuchus M. atopus Locality IQ114
Paleosuchus P. sp.
Podocnemis P. sp.
Purussaurus P. neivensis Locality IQ26 and IQ114 Skull and teeth. A giant caiman.
 

Correlations

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Laventan

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Laventan correlations in South America
Formation Honda Honda Aisol Cura-Mallín Pisco Ipururo Pebas Capadare Urumaco Inés Paraná Map
Basin VSM Honda San Rafael Caldera Pisco Ucayali Amazon Falcón Venezuela Paraná
Pebas Formation (South America)
Country   Colombia   Bolivia   Argentina   Chile   Peru   Venezuela   Argentina
Boreostemma      
Hapalops      
Miocochilius      
Theosodon      
Xenastrapotherium      
Mylodontidae        
Sparassodonta    
Primates  
Rodents              
Birds      
Terror birds  
Reptiles              
megalodon      
Flora  
Insects  
Environments Fluvial Fluvio-deltaic Fluvio-lacustrine Fluvio-deltaic Fluvial
  Laventan volcanoclastics

  Laventan fauna

  Laventan flora
Volcanic Yes

Huayquerian

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Huayquerian correlations in South America
Formation Cerro Azul Ituzaingó Paraná Camacho Raigón Andalhuala Chiquimil Las Flores Maimará Palo Pebas Muyu Rosa Saldungaray Salicas Urumaco Map
Basin Colorado Paraná Hualfín Tontal Andes Salta Amazon Huasi Altiplano BA Velasco Falcón
Pebas Formation (South America)
Country   Argentina   Uruguay   Argentina   Brazil
  Peru
  Bolivia   Argentina   Venezuela
Cardiatherium        
Lagostomus            
Macroeuphractus      
Proeuphractus        
Pronothrotherium    
Pseudotypotherium      
Thylacosmilus      
Xotodon        
Macraucheniidae            
Primates  
Rodents                      
Reptiles            
Birds        
Terror birds      
Flora    
Environments Aeolian-fluvial Fluvio-deltaic Fluvial Fluvio-lacustrine Fluvial Fluvio-lacustrine Fluvio-deltaic
  Huayquerian volcanoclastics

  Huayquerian fauna

  Huayquerian flora
Volcanic Yes

References

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  1. ^ Wesselingh et al., 2006
  2. ^ Sala Gismondi et al., 2006
  3. ^ a b c d e f g h CTA-45 at Fossilworks.org
  4. ^ Amazonian amber at Fossilworks.org
  5. ^ Rasia, Luciano L.; Candela, Adriana M. (2018-05-19). "Reappraisal of the giant caviomorph rodent Phoberomys burmeisteri (Ameghino, 1886) from the late Miocene of northeastern Argentina, and the phylogeny and diversity of Neoepiblemidae". Historical Biology. 30 (4): 486–495. doi:10.1080/08912963.2017.1294168. ISSN 0891-2963. S2CID 90381892.
  6. ^ a b IQ114 at Fossilworks.org

Bibliography

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  • Montoya A., Diana M.; Alonso O., Diego; Pinilla O., Alejandro; Arenas M, José E. (2011), Geología de las Planchas 567, 568, 568bis, 569 and 569bis - 1:200,000 (PDF), Servicio Geológico Colombiano, pp. 1–187, retrieved 2018-06-01
  • Salas Gismondi, R.; Flynn, J.J.; Baby, P.; Tejada Lara, J.V.; Wesselingh, F.P.; Antoine, P-O. (2015), "A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands", Proceedings of the Royal Society B: Biological Sciences, 282 (1804): 20142490, doi:10.1098/rspb.2014.2490, PMC 4375856, PMID 25716785
  • Wesselingh, F.P.; Hoorn, M.C.; Guerrero, J.; Räsänen, M.E.; Romero Pittmann, L.; Salo, J. (2006), "The stratigraphy and regional structure of Miocene deposits in western Amazonia (Peru, Colombia and Brazil), with implications for late Neogene landscape evolution", Scripta Geologica, 133: 291–322, retrieved 2017-08-15

Further reading

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  • Antoine, P.; Abello, J.A.; Adnet, S.; Altamirano Sierra, A.J.; Baby, P.; Billet, G.; Boivin, M.; Calderón, Y.; Candela and J. Chabain, F. Corfu, D. A. Croft, M. Ganerød, C. Jaramillo, S. Klaus, L. Marivaux, R. E. Navarrete, M. J. Orliac, F. Parra, M. E. Pérez, F. Pujos, J. Rage, Anthony Ravel, Céline Robinet, Martin Roddaz, Julia Victoria Tejada Lara, Jorge Vélez-Juarbe, Frank P. Wesselingh and Rodolfo Salas Gismondi, A.R. (2016), "A 60-million-year Cenozoic history of western Amazonian ecosystems in Contamana, eastern Peru" (PDF), Gondwana Research, 31: 30–59, Bibcode:2016GondR..31...30A, doi:10.1016/j.gr.2015.11.001, retrieved 2020-03-19{{citation}}: CS1 maint: multiple names: authors list (link)
  • Marcos C.Bissaro-Júnior, Leonardo Kerber, James L.Crowley, Ana M.Ribeiro, Renato P.Ghilardi, Edson Guilherme, Francisco R.Negri, Jonas P.Souza Filho, Annie S.Hsiou: "Detrital zircon U–Pb geochronology constrains the age of Brazilian Neogene deposits from Western Amazonia." Palaeogeography, Palaeoclimatology, Palaeoecology Volume 516, 15 February 2019, Pages 64–70 doi: 10.1016/j.palaeo.2018.11.032