Pebas Formation

Pebas Formation
Pebas Formation
Stratigraphic range: Early Aquitanian-Tortonian; (Colhuehuapian-Huayquerian); ~21–8 Ma PreꞒ Ꞓ O S D C P T J K Pg N
	The Pebas Mega-Wetland (or Lake Pebas), on the western side of this map, corresponds to the Pebas Formation
Underlies	Marañón Formation
Overlies	Chambira Formation
Area	1,000,000 km2 (390,000 sq mi)
Thickness	~350–1,074 m (1,148–3,524 ft)
Lithology
Primary	Siltstone, mudstone
Other	Coal/lignite
Location
Coordinates	7°24′S 75°00′W / 7.4°S 75.0°W
Approximate paleocoordinates	8°24′S 70°36′W / 8.4°S 70.6°W
Region	Amazon Basin
Country	Brazil; Colombia; Ecuador; Peru
Type section
Named for	Pebas District

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]

Fossil content edit

Fish edit

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

Insects edit

Taxa	Species	Locality	Stratigraphic position	Material	Notes	Images
Macroteleia ^[4]	M. yaguarum				A parasitoid wasp.
Sycorax	S. peruensis				Relatives of moth flies and sand flies.

Mammals edit

Taxa	Species	Locality	Material	Notes
Dinomyidae ^[3]	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 edit

Taxa	Species	Locality	Stratigraphic position	Material	Notes
Caiman ^[3]^[6]	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 ^[3]^[6]	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 edit

Laventan edit

Laventan correlations in South America
Formation	Honda	Honda	Aisol	Cura-Mallín	Pisco	Ipururo	Pebas	Capadare	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										Laventan volcanoclastics Laventan fauna Laventan flora

Huayquerian edit

Huayquerian correlations in South America
Formation	Cerro Azul	Ituzaingó	Camacho	Raigón	Andalhuala	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 edit

^ Wesselingh et al., 2006
^ Sala Gismondi et al., 2006
^ ^a ^b ^c ^d ^e ^f ^g ^h CTA-45 at Fossilworks.org
^ Amazonian amber at Fossilworks.org
^ 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.
^ ^a ^b IQ114 at Fossilworks.org

Bibliography edit

Montoya A., Diana M.; Diego Alonso O.; Alejandro Pinilla O., and José E. Arenas M. 2011. Geología de las Planchas 567, 568, 568bis, 569 and 569bis - 1:200,000, 1–187. Servicio Geológico Colombiano. Accessed 2018-06-01.
Salas Gismondi, R.; J.J. Flynn; P. Baby; J.V. Tejada Lara; F.P. Wesselingh, and P-O. Antoine. 2015. A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands. Proceedings of the Royal Society B: Biological Sciences 282. 20142490. Accessed 2018-05-20.
Wesselingh, F.P.; M.C. Hoorn; J. Guerrero; M.E. Räsänen; L. Romero Pittmann, and J. Salo. 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. Accessed 2017-08-15.