Papers by José Luis Prado
Quaternary
The Pampean Region contains sedimentary sequences with abundant mammal fossil records, which cons... more The Pampean Region contains sedimentary sequences with abundant mammal fossil records, which constitute the chronological outline of the Plio–Pleistocene of South America. These classic localities have been used for more than a century to correlate with other South American regions. Throughout this time, a series of misinterpretations have appeared. To understand the stratigraphic significance of these localities and the geochronological situation of each unit referring to the Pleistocene, a critical historical study of the antecedents was carried out, evaluating the state of each unit. The biostratigraphic studies of the Pampean Region’s mammalian faunas improved the understanding of biogeographic changes taking into account the environmental fluctuations of the Pleistocene.
To reconstruct the paleodiet and habitat preference of gomphotheres, we measured the carbon and o... more To reconstruct the paleodiet and habitat preference of gomphotheres, we measured the carbon and oxygen isotope composi- tion of 32 bone and tooth samples of Stegomastodon platensis (AMEGHINO, 1888) from 10 different Pleistocene localities in Pampean Region (Argentina). In order to compare the different stratigraphic levels we have divided the samples in two groups: middle and late Pleistocene. Samples from the middle Pleistocene are more homogeneous, with a range of 13 C values between -9.0 to -5.9‰. This data indicates a mixed C 3 y C 4 diet. On the contrary, samples from late Pleistocene show a wide range of diet adaptation (with a range 13 C values between -12.11 to -6.09 ‰), since specimens that indicate an exclusively C 3 diet from latest Pleistocene, to others with a mixed- feeder diet. Several nutritional hypotheses to explain late Pleistocene extinctions adopt the assumption that extinct taxa had specialized diets. The resource partitioning preference of Stegomastodon platen...
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 2019
A comparative study was made with the known record of equids species in South America, identifyin... more A comparative study was made with the known record of equids species in South America, identifying the remains as Equus neogeus, Hippidion devillei, and Hippidion principale. These data increase the record of Equidae in South America and provide new evidence about the chronological and geographical distribution. The sedimentary deposits of the Lujan Formation outcropping at Tapalqué creek (4 to 120 ky) were accumulated through fluvial processes. This Formation comprises a rich vertebrate fauna corresponding to the Lujanian South American Land Mammal Age, which includes numerous and diverse vertebrate remains. The taphonomic analysis indicates that the faunistic assemblage was formed and was subject to diagenetic processes without distinction of its action in the fossiliferous levels, that can be recognized as fluvial deposits.
Estudios Geológicos, 2018
En el presente trabajo se describen restos de caballos del Pleistoceno procedentes de afloramient... more En el presente trabajo se describen restos de caballos del Pleistoceno procedentes de afloramientos en el río Abaucán de la localidad de Tinogasta (Catamarca). El estudio comparativo se realizó con los registros conocidos de este grupo de mamíferos en América del Sur y se identificó comoEquus neogeus. Es el primer registro de esta especie en el Pleistoceno tardío de Catamarca (Argentina). Estos datos representan un nuevo registro de Equidae en América del Sur y aportan nuevas evidencias sobre su cronología y distribución geográfica.Equus neogeus es el caballo más grande y más grácil de los de América del Sur y se encuentra en su zona más oriental. Hasta ahora no se habían registrado fuera de las tierras bajas de Argentina, Uruguay y Brasil. Este es el primer registro en regiones más altas altitudinalmente. Además, el contexto litoestratigráfico permite obtener consideraciones paleoecológicas. Desde el punto de vista cronoestratigráfico los niveles fosilíferos se refieren a la edad L...
Biology letters, 2015
Hippidions were equids with very distinctive anatomical features. They lived in South America 2.5... more Hippidions were equids with very distinctive anatomical features. They lived in South America 2.5 million years ago (Ma) until their extinction approximately 10 000 years ago. The evolutionary origen of the three known Hippidion morphospecies is still disputed. Based on palaeontological data, Hippidion could have diverged from the lineage leading to modern equids before 10 Ma. In contrast, a much later divergence date, with Hippidion nesting within modern equids, was indicated by partial ancient mitochondrial DNA sequences. Here, we characterized eight Hippidion complete mitochondrial genomes at 3.4-386.3-fold coverage using target-enrichment capture and next-generation sequencing. Our dataset reveals that the two morphospecies sequenced (H. saldiasi and H. principale) formed a monophyletic clade, basal to extant and extinct Equus lineages. This contrasts with previous genetic analyses and supports Hippidion as a distinct genus, in agreement with palaeontological models. We date the...
Zoological Journal of the Linnean Society, 1993
Quaternary Science Reviews, 2012
The modern South American mammalian assemblage was determined by the closure of the Panama isthmu... more The modern South American mammalian assemblage was determined by the closure of the Panama isthmus (w2.7e3.1 Ma) and later on, by profound climatic and environmental fluctuations occurred during the Quaternary as well as by the appearance of humans in the continent. In the present study, stable isotope analyses (d 13 C, d 18 O CO3 and d 18 O PO4) have been carried out on PleistoceneeHolocene northern inmigrant and endemic taxa from a broad latitudinal and altitudinal distribution in South America with the purpose of characterizing their paleoecology and the effects of the paleobiogeographic distribution on stable isotope results. Equids and gomphotheres show a wide range of d 13 C values going from woodlands to pure C 4 grasslands. In the case of equids, Hippidion shows lower d 13 C values than Equus in the Late Pleistocene, whereas, in the case of gomphotheres, Cuvieronius and Stegomastodon differ in their d 18 O values on account on differences in their paleobiogeography with the former found in the Andean corridor and the latter dispersing through an eastern route. Isotope data of the rest of taxa (immigrant and endemic) are in general in good agreement with other previous isotopic and nonisotopic studies. The latitude threshold between mixed C 3 eC 4 and pure C 3 conditions have been pinpointed at w33 S in the Middle and the Late Pleistocene. Mammalian d 18 O values are intimately related to latitudinal and altitudinal distribution, with the latter exerting an overriding influence independently of latitude. Calculated altitudinal gradients (between À0.23&/100 m and À0.40&/100 m) are within the range of modern gradients.
Quaternary Science Reviews, 2000
In this letter we comment on two recent papers by Forsten (1998, 1999). In the former, the author... more In this letter we comment on two recent papers by Forsten (1998, 1999). In the former, the author discusses the possibility of using horse species as stratigraphic markers. The latter is a review of Equus stenonis forms, and also emphasises this approach. Both papers are very interesting since one of the most quali"ed specialists on fossil horses contributes there with her own ideas to the open debate on the systematic and stratigraphic value of the European horses. However, we believe that some aspects of Forsten's papers can be analysed in a di!erent way.
Proceedings of the National Academy of Sciences, 2009
The rich fossil record of the family Equidae (Mammalia: Perissodactyla) over the past 55 MY has m... more The rich fossil record of the family Equidae (Mammalia: Perissodactyla) over the past 55 MY has made it an icon for the patterns and processes of macroevolution. Despite this, many aspects of equid phylogenetic relationships and taxonomy remain unresolved. Recent genetic analyses of extinct equids have revealed unexpected evolutionary patterns and a need for major revisions at the generic, subgeneric, and species levels. To investigate this issue we examine 35 ancient equid specimens from four geographic regions (South America, Europe, Southwest Asia, and South Africa), of which 22 delivered 87–688 bp of reproducible aDNA mitochondrial sequence. Phylogenetic analyses support a major revision of the recent evolutionary history of equids and reveal two new species, a South American hippidion and a descendant of a basal lineage potentially related to Middle Pleistocene equids. Sequences from specimens assigned to the giant extinct Cape zebra,Equus capensis, formed a separate clade with...
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen, 2013
ABSTRACT The fossil mammal locality from the El Polvorín limestone Quarry in Calera Avellaneda (O... more ABSTRACT The fossil mammal locality from the El Polvorín limestone Quarry in Calera Avellaneda (Olavarría, Argentina) is known for its Quaternary mammals. This paper describes new specimens of equids. The comparative study with other horses, from different localities of South America, mostly Argentina and Brazil, allowed identifying the specimen as Equus (Amerhippus) neogeus Lund. This represents a new locality for this species, assigned to the late Pleistocene (Lujanian Stage/Age, c. 130-12 ka BP). The fauna associated with this stratigraphic level is consistent with a lapse of time dominated by fauna adapted to arid and cold conditions.
Journal of Vertebrate Paleontology, 1998
Journal of Molecular Evolution, 2008
Hippidions are past members of the equid lineage which appeared in the South American fossil reco... more Hippidions are past members of the equid lineage which appeared in the South American fossil record around 2.5 Ma but then became extinct during the great late Pleistocene megafaunal extinction. According to fossil records and numerous dental, cranial, and postcranial characters, Hippidion and Equus lineages were expected to cluster in two distinct phylogenetic groups that diverged at least 10 MY, long before the emergence of the first Equus. This is a reply to the Comment published by Alberdi et al. (2005).
Integrative Zoology, 2014
This article has been accepted for publication and undergone full peer review but has not been th... more This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as
Evolutionary Ecology, 2008
The Plio-Pleistocene carnivores from the NorthWestern Mediterranean (Iberian and Italian peninsul... more The Plio-Pleistocene carnivores from the NorthWestern Mediterranean (Iberian and Italian peninsulas, and France) are analysed in order to investigate whether their diversity over the last 5.3 Ma was influenced by disturbances of the physical environment. Trends in species diversity over time were analysed in successive unequal time intervals, which were reassessed on the basis of local biochronological schemes. By using a taxon-free characterisation, species were assigned to various ecological categories in accordance with feeding and hunting behaviour, preferred habitat, and average body mass. Principal Component Analysis identified the most important ecological variables in recognising changes among the carnivoran Faunal Complexes that characterised each time interval. The results obtained support the hypothesis that some complex, though not always direct relationships exist between environmental changes and shifts in the diversity of Carnivora (especially for forest dwelling carnivorans). However, progressive changes in Electronic supplementary material The online version of this article (
Estudios Geológicos, 2011
Los isótopos del carbono preservados en 166 muestras de dientes y huesos fósiles son un dato clav... more Los isótopos del carbono preservados en 166 muestras de dientes y huesos fósiles son un dato clave para entender la ecología de los de caballos y gonfoterios durante el Plio-Pleistoceno en América del Sur. Para analizar los cambios en las reconstrucciones de la dieta durante este lapso temporal hemos dividido las muestras en 19 grupos, teniendo en cuenta la sistemática y la cronología de cada localidad. En este estudio, las dietas de ambos grupos son evaluadas para probar las hipótesis sobre su extinción. El alto fraccionamiento en el uso de los recursos entre los herbívoros que asume la hipótesis del desequilibrio co-evolutivo es sustentada por los datos isotópicos de los caballos del Pleistoceno tardío. Hippidion y Equus tenían una dieta muy diferente. En contraste, las especies de gonfoterios de finales del Pleistoceno parecen tener una dieta menos especializada con una combinación de plantas C3 y C4, que está en consonancia con los supuestos de la hipótesis del mosaico de nutrie...
Estudios Geológicos, 2008
Se describen restos bien conservados de gonfoterios (Mammalia, Proboscidea) encontrados en los ni... more Se describen restos bien conservados de gonfoterios (Mammalia, Proboscidea) encontrados en los niveles pleistocenos que afloran en los acantilados costeros de Santa Clara del Mar (Mar del Plata, Argentina). Se analizan algunos de sus caracteres más importantes y se compara con otros gonfoterios provenientes de distintas localidades de Argentina, Brasil y Bolivia. El estudio comparativo, mediante análisis multivariante del m3, permitió su identificación como Stegomastodon platensis. Nosotros consideramos que todos los Gomphotheriidae del territorio actual de Argentina deberían incluirse en un único género y una única especie: Stegomastodon platensis. Esta especie parece estar mejor adaptada a vivir en latitudes medias, y en condiciones climáticas templadas. Se discuten sus posibles vías de desplazamiento desde el norte hacia zonas o áreas más australes. Stegomastodon de América del Sur es una forma de gran tamaño, que se encuentra a lo largo de la ruta del este y en algunas áreas costeras de Ecuador y Perú. En el presente artículo se incluyen algunas consideraciones paleoecológicas y paleogeográficas de esta especie de América del Sur. A partir de una datación radiométrica por AMS de una muestra de esmalte dentario se sitúan estratigráficamente los restos de Santa Clara del Mar en el Pleistoceno superior (17.880 ± 60 AP).
Estudios Geológicos, 2008
En América del Sur, la familia Equidae se encuentra representada por dos grupos: equiformes e hip... more En América del Sur, la familia Equidae se encuentra representada por dos grupos: equiformes e hipidiformes. En general, ambos grupos presentan formas de montaña y llanura, con adaptaciones similares. Sin embargo, en el extremo austral de la Patagonia-que comprende la cuenca del río Deseado, la Patagonia extraandina y Tierra del Fuego-se ha registrado una especie sumamente particular de hipidiforme denominado Hippidion saldiasi
Estudios Geológicos, 1999
La secuencia del Pleistoceno tardío-Holoceno temprano en Arroyo Seco 2 es una de las más completa... more La secuencia del Pleistoceno tardío-Holoceno temprano en Arroyo Seco 2 es una de las más completas del registro de la Región Pampeana. Se distinguen cuatro unidades estratigráficas, tres de ellas contienen abundantes restos de pequeños mamíferos fósiles. Se analizan los huesos fósiles de estas unidades con el fin de determinar los procesos tafonómicos y el hábitat en el que tuvo lugar la acumulación que dio lugar al yacimiento. La mayor parte de los huesos fósiles están rotos con posterioridad al enterramiento. Los huesos procedentes de las unidades inferiores están recubiertos de manganeso (Mn) debido a la oscilación de los niveles del agua como consecuencia de reiterados encharcamientos. Entre la fauna de micromamíferos identificamos tres especies de armadillo (Chaetophractus villosus, Dasypus hybridus y Zaedyus pichiy) y cuatro de roedores (Akodon azarae, Rheitrodon auritus, Ctenomys talarum y Lagostomus maximus). Los datos sobre micromamíferos registrados, sumados a la evidencia de megafauna, indican una transición de condiciones templadas y semiáridas a más húmedas entre 12.000 y 8.500 años AP.
Estudios Geológicos, 2013
En este estudio se describen dos nuevos cráneos referidos a Hippidion principale (Lund) y varios ... more En este estudio se describen dos nuevos cráneos referidos a Hippidion principale (Lund) y varios elementos del esqueleto apendicular referidos a H. devillei procedentes de dos localidades clásicas de la provincia de Buenos Aires, las márgenes de los ríos Salado y Quequén Grande. Para la identificación taxonómica de los restos apendiculares, se realizó un análisis multivariante en el que se incluyeron los metacarpianos y falanges descritos y los registrados en varias localidades de Argentina y Brasil. Para la determinación de los cráneos se realizó un estudio comparativo con otros cráneos de diversas localidades. Estos hallazgos incrementan el registro de Hippidion en América del Sur y aportan nuevas evidencias sobre la cronología de sus especies en Argentina. Se realizó una datación por AMS para el ejemplar de Río Salado (MHM-P54) que ha suministrado una edad 14 C 14120 ± 50 BP. En general, los sedimentos portadores en ambas localidades son referibles a la Edad Lujanense, Biozona de Equus (Amerhippus) neogeus.
BMC Ecology, 2011
BackgroundStable isotope ratios (13C/12C and18O/16O) in fossil teeth and bone provide key archive... more BackgroundStable isotope ratios (13C/12C and18O/16O) in fossil teeth and bone provide key archives for understanding the ecology of extinct horses during the Plio-Pleistocene in South America; however, what happened in areas of sympatry betweenEquus (Amerhippus)andHippidionis less understood.ResultsHere, we use stable carbon and oxygen isotopes preserved in 67 fossil tooth and bone samples for seven species of horses from 25 different localities to document the magnitude of the dietary shifts of horses and ancient floral change during the Plio-Pleistocene. Dietary reconstructions inferred from stable isotopes of both genera of horses present in South America document dietary separation and environmental changes in ancient ecosystems, including C3/C4transitions. Stable isotope data demonstrate changes in C4grass consumption, inter-species dietary partitioning and variation in isotopic niche breadth of mixed feeders with latitudinal gradient.ConclusionsThe data forHippidionindicate a ...
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Papers by José Luis Prado