CONSTRAINING C4 EXPANSION IN CONTINENTAL SOUTH AMERICA DURING THE LATE MIOCENE-PLIOCENE USING D13C ISOTOPIC PROXIES AND COMPLEX ORGANIC CARBON MOLECULES

2020 ◽  
Author(s):  
Adit Ghosh ◽  
◽  
Jennifer M. Cotton ◽  
Ethan G. Hyland ◽  
Maria Sol Raigemborn ◽  
...  
Keyword(s):  
Organic Carbon ◽  
South America ◽  
Late Miocene ◽  
Isotopic Proxies ◽  
Carbon Molecules ◽  
Complex Organic

A new argyrolagoid (Mammalia: Marsupialia) from the middle Miocene of Bolivia

1988 ◽  
Vol 62 (3) ◽  
pp. 463-467 ◽  
Author(s):  
Villarroel A. Carlos ◽  
Larry G. Marshall
Keyword(s):  
South America ◽  
Late Miocene ◽  
Adaptive Radiation ◽  
Middle Miocene ◽  
Northwest Argentina ◽  
The Family ◽  
Size And Structure

A new argyrolagoid marsupial, Hondalagus altiplanensis n. gen., n. sp., from the middle Miocene (Santacrucian–Friasian) age locality of Quebrada Honda in southernmost Bolivia represents the smallest and most specialized member of the family Argyrolagidae known. The lower molars are hypselodont and lack vertical grooves labially and lingually, and M4 is greatly reduced relative to M3. In overall size and structure, H. altiplanensis compares best with Microtragulus catamarcensis (Kraglievich, 1931) from rocks of late Miocene (Huayquerian) age in northwest Argentina. Hondalagus altiplanensis demonstrates that the adaptive radiation of argyrolagoids was much greater than previously envisioned, and that generic differentiation of known taxa occurred no later than early–middle Miocene time in South America.

Spatiotemporal palaeodiversity patterns of modern crocodiles (Crocodyliformes: Eusuchia)

2019 ◽  
Vol 189 (2) ◽  
pp. 635-656 ◽  
Author(s):  
Ane De Celis ◽  
Iván Narváez ◽  
Francisco Ortega
Keyword(s):  
South America ◽  
Least Squares ◽  
Late Miocene ◽  
North American ◽  
Fossil Record ◽  
Generalized Least Squares ◽  
Global Scale ◽  
Biotic Factors ◽  
Species Dynamics ◽  
Over Time

Abstract Eusuchia is a crocodyliform clade with a rich and diverse fossil record dating back to the Mesozoic. There are several recent studies that analyse crocodyliform palaeodiversity over time, but none of them focuses exclusively on eusuchians. Thus, we estimated subsampled eusuchian palaeodiversity species dynamics over time not only at a global scale, but also by continents and main crocodylian lineages (Alligatoroidea, Crocodyloidea and Gavialoidea). These estimates reveal complex spatiotemporal palaeodiversity patterns, in which two maxima can be detected: the first during the Palaeocene and the second, which is also the biggest, in the middle-late Miocene. The Palaeocene shift is related to a North American alligatoroid diversification, whereas the middle–late Miocene maximum is related to a diversification of the three main Crocodylia lineages in Gondwanan land masses, but especially in South America. Additionally, a model-based study using generalized least squares was carried out to analyse the relationships between different abiotic and sampling proxies and eusuchian palaeodiversity. The results show that palaeotemperature is the most important factor amongst the analysed proxies, in accordance with previous studies. However, the results suggest that, along with palaeotemperature, other abiotic and/or biotic factors might also be driving eusuchian palaeodiversity dynamics.

scholarly journals IMPACTO DE Guadua paraguayana SOBRE REMANESCENTE DE FLORESTA OMBRÓFILA MISTA ALUVIAL – UMA ABORDAGEM BIOGEOQUÍMICA

FLORESTA ◽  
2012 ◽  
Vol 42 (2) ◽  
pp. 355
Author(s):  
Franklin Galvão ◽  
Cátia Regina Augustin ◽  
Gustavo Ribas Curcio ◽  
Nelson Cosmo ◽  
Carina Kozera ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Organic Carbon ◽  
South America ◽  
Nutrient Cycling ◽  
Carbon Flux ◽  
Half Life ◽  
Litter Production ◽  
Organic Carbon Flux ◽  
Production Values ◽  
Alluvial Forest

 Guadua paraguayana Döll, um bambu nativo da porção meridional da América do Sul particularmente agressivo, está invadindo áreas de preservação permanente no segundo planalto paranaense, com supressão da vegetação instalada e modificações nos padrões de sucessão local. Após estabelecer sua autoecologia, para melhor avaliar seu impacto sobre um dos últimos remanescentes da Floresta Ombrófila Mista Aluvial (FOMA), principalmente na ciclagem de nutrientes e no fluxo de carbono orgânico para o ambiente, estudou-se a composição química da espécie, a produção e decomposição de serapilheira e a distribuição das raízes. A área em estudo (25º 13’20,8” S e 50º04’26,8” W, Ponta Grossa/PR) é uma planície de inundação degradada às margens do rio Tibagi. Os valores anuais de produção de serapilheira de G. paraguayana foram estimados em 7.500 kg/ha, com meia vida superior a 260 dias para os limbos e 360 dias para as bainhas foliares. No período analisado, as folhas retornaram ao ambiente 164,27 kg/ha de macronutrientes. Com base na concentração de carbono da folha, o fluxo de carbono orgânico da vegetação para o solo foi estimado em 2.800 kg/ha/ano. Em comparação com os valores de FOMA melhor preservada, a presença dominante desse bambu reduz a quantidade de nutrientes e de carbono devolvidos ao meio.Palavras-chave: Bambu; serapilheira; ciclagem de nutrientes. AbstractGuadua paraguayana’s impacts on a remaining of Subtropical Ombrophilous Alluvial Forest – a biogeochemistry approach. Guadua paraguayana Döll, a particularly aggressive native bamboo from the southern portion of South America, is invading permanent preservation areas located in the second plateau of Parana, causing suppression of the current vegetation and modifications in the local succession patterns. After determine its autecology, to better assess its impact on one of the last remaining of Subtropical Ombrophilous Alluvial Forest, mainly on nutrient cycling and organic carbon flux to the environment, it was studied the species’ chemical composition and the production and decomposition of litter, and roots distribution. The focused area (25º13’20.8” S and 50º04’26.8” W, Ponta Grossa-PR, BR) is a degraded floodplain of Tibagi river. The annual litter production values of G. paraguayana were estimated at 7,500kg/ha, with a half-life of more than 260 days for the bladesand 360 days for the sheaths. Within this period, the photosynthetic leaves returned to the environment (bars) 164.27kg/ha of macronutrients. Based on the concentration of carbon in the leaf, the flux of organic carbon from vegetation to soil was estimated at 2,800kg/ha/year. The dominant presence of bamboo in the area decreases the amount of carbon and nutrients returned to the environment, when confronted with Subtropical Ombrophilous Alluvial Forest better preserved. Keywords: Bamboo; litter; nutrient cycling. 

Stratigraphy and structure of regionally-isolated hydrocarbon occurrences in the Azua Basin, south-central Dominican Republic (Northeastern Caribbean)

2020 ◽  
pp. SP504-2019-241 ◽  
Author(s):  
Paul Mann ◽  
Stephen Pierce
Keyword(s):  
Organic Carbon ◽  
Dominican Republic ◽  
Total Organic Carbon ◽  
Late Miocene ◽  
Hydrocarbon Exploration ◽  
Reservoir Rock ◽  
The Bahamas ◽  
South Central ◽  
Oil Seeps ◽  
Oblique Convergence

AbstractOil seeps and small-production oilfields in south-central Hispaniola are regionally isolated from much larger hydrocarbon provinces in the circum-Gulf of Mexico and northern South America. In this study, we evaluate the tectonic, stratigraphic and structural setting of these hydrocarbon occurrences. The zone of late Miocene to Recent oblique convergence includes the Bahamas Platform, Cretaceous and Paleogene arc rocks in Hispaniola, and the Cretaceous Caribbean oceanic plateau. Twentieth-century hydrocarbon exploration in Hispaniola has been concentrated on the elongate, NW- to WNW-trending, thrust- and strike-slip fault-bounded Cibao, San Juan–Azua and Enriquillo basins. Analyses of Cretaceous to Neogene rocks in the Dominican Republic have revealed that most rocks contain poor to marginal total organic carbon values. In the Azua Basin, a shallow marine, basin-edge facies of the middle Miocene Sombrerito Formation underlies the area of natural oil seeps and limited historical oil production and exhibits good to excellent total organic carbon values greater than 1%. Structural traps for oil at the Maleno and Higuerito oilfields of the Dominican Republic are large anticlines formed in post-late Miocene time. Reservoir rock for oil at the Maleno and Higuerito oilfields of the Dominican Republic is submarine fan-deposited sandstone of the late Miocene Trinchera Formation.

First fossil of the Giant Armored Catfish Acanthicus (Siluriformes, Loricariidae) from the Late Miocene of Entre Ríos Province, Argentina

Zootaxa ◽  
2020 ◽  
Vol 4808 (3) ◽  
pp. 571-581
Author(s):  
SERGIO BOGAN ◽  
FEDERICO L. AGNOLIN
Keyword(s):  
South America ◽  
Late Miocene ◽  
Large River ◽  
River Channels ◽  
Present Contribution ◽  
Neotropical Fishes ◽  
Northern Half ◽  
Late Neogene ◽  
Single Genus ◽  
Entre Rios

Loricariidae is a very diverse lineage of Neotropical fishes, being the most speciose family of the order Siluriformes. However, the loricariid fossil record is still very sparse. The aim of the present contribution is to describe in detail several bones belonging to the loricariid genus Acanthicus coming from late Miocene beds located at the Paraná River cliffs, Entre Ríos province, Argentina. Fishes of the Acanthicus clade are currently restricted to the northern half of South America, being mainly distributed in the Orinoco and Amazonas basins, with a single genus reaching the Paraná-Plata basin. Acanthicus adds to the list of several taxa that are shared by the Miocene of Paraná, Amazonas and Orinoco basins, but that nowadays are absent in the former (e.g., Colossoma, Phractocephalus, and Brachyplatystoma), and are typical of large river channels. This report of Acanthicus supports a close affinity between freshwater faunas of the Paraná, Orinoco, and Amazonas basins. Miocene fossils of freshwater fishes recorded in Paraná beds shed light on the connections between ancient basins of South America and also indicate that several fish clades suffered regional extinctions during the late Neogene or the beginning of the Quaternary. 

scholarly journals A new enigmatic Late Miocene mylodontoid sloth from northern South America

2015 ◽  
Vol 2 (4) ◽  
pp. 150138 ◽  
Author(s):  
Ascanio D. Rincón ◽  
H. Gregory McDonald ◽  
Andrés Solórzano ◽  
Mónica Núñez Flores ◽  
Damián Ruiz-Ramoni
Keyword(s):  
South America ◽  
Late Miocene ◽  
Northern South America

A new species ofScirrotheriumEdmund & Theodor, 1997 (Xenarthra, Cingulata, Pampatheriidae) from the late Miocene of South America

2013 ◽  
Vol 37 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Flávio Góis ◽  
Gustavo Juan Scillato-Yané ◽  
Alfredo Armando Carlini ◽  
Edson Guilherme
Keyword(s):  
New Species ◽  
South America ◽  
Late Miocene ◽  
A New Species

New Late Miocene Dromomerycine Artiodactyl from the Amazon Basin: Implications for Interchange Dynamics

2014 ◽  
Vol 88 (3) ◽  
pp. 434-443 ◽  
Author(s):  
Donald R. Prothero ◽  
Kenneth E. Campbell ◽  
Brian L. Beatty ◽  
Carl D. Frailey
Keyword(s):  
North America ◽  
South America ◽  
Late Miocene ◽  
Amazon Basin ◽  
New Taxon ◽  
Isthmus Of Panama ◽  
Great American Biotic Interchange ◽  
American Immigrant ◽  
Early Late ◽  
Ground Sloths

A new dromomerycine palaeomerycid artiodactyl, Surameryx acrensis new genus new species, from upper Miocene deposits of the Amazon Basin documents the first and only known occurrence of this Northern Hemisphere group in South America. Osteological characters place the new taxon among the earliest known dromomerycine artiodactyls, most similar to Barbouromeryx trigonocorneus, which lived in North America during the early to middle Miocene, 20–16 Ma. Although it has long been assumed that the Great American Biotic Interchange (GABI) began with the closure of the Isthmus of Panama in the late Pliocene, or ca. 3.0–2.5 Ma, the presence of this North American immigrant in Amazonia is further evidence that terrestrial connections between North America and South America through Panama existed as early as the early late Miocene, or ca. 9.5 Ma. This early interchange date was previously indicated by approximately coeval specimens of proboscideans, peccaries, and tapirs in South America and ground sloths in North America. Although palaeomerycids apparently never flourished in South America, proboscideans thrived there until the end of the Pleistocene, and peccaries and tapirs diversified and still live there today.

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