Upper Cenozoic chronostratigraphy of the southwestern Amazon Basin

Campbell, Kenneth E.; Heizler, M. T.; Frailey, Carl D.; Romero-Pittman, Lidia; Prothero, Donald R.

doi:10.1130/0091-7613(2001)029<0595:uccots>2.0.co;2

Cited by 99 publications

(110 citation statements)

References 14 publications

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“…The lack of a river effect in the western part of the Amazon, when compared to its central and eastern parts, is probably explained by the younger age of the western Amazonian lowlands. Although the Brazilian and Guianan shields have been geologically stable for the last 30-50 million years (Irion et al 1995), the southwestern part of Amazonia began to take its current shape only in the last 2.5 million years or so (Late Pliocene; Hoorn et al 1995;Campbell et al 2001). Therefore, western Amazonian rivers are younger and less stable than rivers located on the Brazilian shield, and they experience frequent lateral channel migration responsible for across river transfer of large pieces of land (Salo et al 1986;Colwell 2000).…”

Section: The Riverine Barrier Hypothesismentioning

confidence: 99%

Historical Diversification of a Terra-Firme Forest Bird Superspecies: A Phylogeographic Perspective on the Role of Different Hypotheses of Amazonian Diversification

2004

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Abstract. Among those few hypotheses of Amazonian diversification amenable to falsification by phylogenetic and population genetics methods, three can be singled out because of their general application to vertebrates: the riverine barrier, the refuge, and the Miocene marine incursion hypotheses. I used phylogenetic and population genetics methods to reconstruct the diversification history of the upland (terra-firme) forest superspecies Xiphorhynchus spixii/elegans (Aves: Dendrocolaptidae) in Amazonia, and to evaluate predictions of the riverine barrier, refuge, and Miocene marine incursion hypotheses. Phylogeographic and population genetics analyses of the X. spixii/elegans superspecies indicated that the main prediction of the riverine barrier hypothesis (that sister lineages occur across major rivers) hold only for populations separated by ''clear-water'' rivers located on the Brazilian shield, in central and eastern Amazonia; in contrast, ''white-water'' rivers located in western Amazonia did not represent areas of primary divergence for populations of this superspecies. The main prediction derived from the refuge hypothesis (that populations of the X. spixii/elegans superspecies would show signs of past population bottlenecks and recent demographic expansions) was supported only for populations found in western Amazonia, where paleoecological data have failed to support past rainforest fragmentation and expansion of open vegetation types; conversely, populations from the eastern and central parts of Amazonia, where paleoecological data are consistent with an historical interplay between rainforest and open vegetation types, did not show population genetics attributes expected under the refuge hypothesis. Phylogeographic and population genetics data were consistent with the prediction made by the Miocene marine incursion hypothesis that populations of the X. spixii/elegans superspecies found on the Brazilian shield were older than populations from other parts of Amazonia. In contrast, the phylogeny obtained for lineages of this superspecies falsified the predicted monophyly of Brazilian shield populations, as postulated by the Miocene marine incursion hypothesis. In general, important predictions of both riverine barrier and Miocene marine incursion hypotheses were supported, indicating that they are not mutually exclusive; in fact, the data presented herein suggest that an interaction among geology, sea level changes, and hydrography created opportunities for cladogenesis in the X. spixii/elegans superspecies at different temporal and geographical scales.Key words. Aves, Amazonia, Miocene marine incursion hypothesis, phylogeography, population genetics, refuge hypothesis, riverine barrier hypothesis.Received March 10, 2003. Accepted February 10, 2004 The bird fauna of the Amazon lowlands in South America is the richest in the world, with over 1000 species, of which about 265 are endemic (Stotz et al. 1996;Nores 2000). As early as 1852, the British naturalist Alfred Russel Wallace put forward an evolutionary...

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Section: The Riverine Barrier Hypothesismentioning

confidence: 99%

Historical Diversification of a Terra-Firme Forest Bird Superspecies: A Phylogeographic Perspective on the Role of Different Hypotheses of Amazonian Diversification

2004

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“…Räsänen et al (1995) attributed at least part of the postulated lacustrine strata to the Miocene and Clapperton (1993) felt that this "megaflood" hypothesis should not be taken seriously. Two age dates for upper Cenozoic volcanic ash deposits from easternmost Peru have become available (9 and 3 million years before present) and stablish approximate time constraints for the last major cycle of Cenozoic deposition in southwestern Amazonia (Campbell et al, 2001). …”

Section: Lagoon Model or Lake Modelmentioning

confidence: 99%

Hypotheses to explain the origin of species in Amazonia

Haffer¹

2008

Braz. J. Biol.

198

176

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The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch ‡ cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm p...

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“…En este trabajo Woodburne anticipa la entrada de la familia Gomphotheriidae al GABI2 (en torno a 1.8 Ma). Si bien, en la literatura está citada la presencia de Amahuacatherium peruvium, gonfoterio del Mioceno en la Formación Madre de Dios en Perú (Campbell et al, 2000(Campbell et al, , 2001(Campbell et al, , 2010 datada en más antiguo de 9.0 Ma. consideran que los restos de Gomphotheriidae de la Formación Madre de Dios (Perú) son morfológicamente idénticos a los restos de Stegomastodon de otras localidades de América del Sur y biométri-camente se encuentran claramente en la parte central de la distribución de los otros restos de m3 de gonfoterio de América del Sur.…”

Section: Paleontología Sistemáticaunclassified

“…Desde el punto de vista geológico y a la vista de todos los datos indicados por Campbell et al (2000), estos autores también consideran difícil de determinar la proveniencia exacta de los restos. En trabajos posteriores Campbell et al (2001Campbell et al ( , 2010 aunque correlacionan el afloramiento con las columnas paleomagnéticas realizadas en zonas algo distantes del lugar del yacimiento situado en su entorno, se adivina complejo seguir estas correlaciones en una zona complicada geológicamente como apunta Latrubesse et al (2007Latrubesse et al ( , 1010, quienes cuestionan también estas correlaciones.…”

Section: Paleontología Sistemáticaunclassified

Équidos y Gonfoterios del Pleistoceno tardío de San Pedro, provincia de Buenos Aires, Argentina

Prado¹,

Alberdi²

2011

Estud. geol.

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IntroducciónLos registros de équidos y gonfoterios en el cuaternario de la provincia de Buenos Aires son relativamente frecuentes. Muchos de estos hallazgos han sido de suma utilidad para reconocer secuencias estratigráficas portadoras de mamíferos que constituyen la escala cronológica del Cuaternario en la región (Cione et al., 2007). Durante la década de 1990, estudios bioestratigráficos muy detallados permitieron postular que en la región Pampeana se sucedieron notables cambios en la distribución de los mamíferos vinculados a la alternancia de ambientes glaciales e interglaciares durante el Pleistoceno Cione & Tonni, 1995). La distribución actual de la mastofauna indica que en esta región se registra un ecotono entre la subregión Guayano-Brasileña y Patagó- Equidos y gonfoterios del RESUMENLos mamíferos fósiles de la localidad de San Pedro (provincia de Buenos Aires, Argentina) son escasamente conocidos. En este artículo se describen los ejemplares mejor conservados de Equidae y Gomphotheriidae. Estos restos provienen del yacimiento "Campo Spósito", ubicado en las proximidades de la ciudad de San Pedro. Los sedimentos portadores son referibles al Piso/Edad Lujanense, Biozona de Equus (Amerhippus) neogeus. Se realizó un estudio comparativo con caballos y gonfoterios de Argentina y Brasil para identificar los siguientes taxa: Hippidion principale, Equus (Amerhippus) neogeus y Stegomastodon cf. S. platensis. Se obtuvieron dos dataciones por Luminiscencia Ópticamente Estimulada para la secuencias estratigráfica de: 37626±4198 y 41554±3756 años AP, respectivamente. Estos datos sitúan el yacimiento en el Pleistoceno Superior (estadio 3 del oxígeno isotópico).

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Upper Cenozoic chronostratigraphy of the southwestern Amazon Basin

Cited by 99 publications

References 14 publications

Historical Diversification of a Terra-Firme Forest Bird Superspecies: A Phylogeographic Perspective on the Role of Different Hypotheses of Amazonian Diversification

Historical Diversification of a Terra-Firme Forest Bird Superspecies: A Phylogeographic Perspective on the Role of Different Hypotheses of Amazonian Diversification

Hypotheses to explain the origin of species in Amazonia

Équidos y Gonfoterios del Pleistoceno tardío de San Pedro, provincia de Buenos Aires, Argentina

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