A Quaternary record of the big-eyed bat Chiroderma villosum (Chiroptera: Phyllostomidae) with a revised lower molar terminology

Abstract We report the first Quaternary record of the big-eyed bat Chiroderma villosum from South America based on a left mandible fragment collected in the Gruta dos Brejões, late Quaternary of northeastern Brazil. This material has been identified over the course of our revisionary work of the genus Chiroderma, including all species distributed in South America (Chiroderma doriae, Chiroderma salvini, Chiroderma trinitatum, Chiroderma villosum and Chiroderma vizottoi). Our results revealed that several characters of the second lower molar (m2), and of the posterior mandible may be used to identify and to diagnose the South American Chiroderma. We also revisited the historical interpretation of homologies of the lower molar cusps of Chiroderma, and propose a revised molar cusp terminology.

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A new fossil cricetid (Rodentia, Sigmodontinae) from northeastern Brazil with remarks on small mammal extinctions in the tropical Quaternary

Journal of Mammalogy ◽

10.1093/jmammal/gyaa066 ◽

2020 ◽

Vol 101 (4) ◽

pp. 1133-1147

Author(s):

Simone B das Neves ◽

Ulyses F J Pardiñas ◽

Patrícia Hadler ◽

Elver L Mayer ◽

Ana M Ribeiro

Keyword(s):

New Species ◽

South America ◽

Small Mammal ◽

Late Quaternary ◽

Northeastern Brazil ◽

The South ◽

Quaternary Deposits ◽

Extant Species ◽

Genetic Features ◽

History Of

Abstract The rare cricetid rodent Bibimys Massoia, 1980 contains three extant species that are distributed in the lowlands of eastern South America between 35°S and 20°S and distinguished mostly by subtle morphological and genetic features. Several fragmented jaws belonging to this genus were recovered from Late Quaternary deposits located in northeastern Brazil, forming part of a rich archaeological and paleontological small mammal assemblage that has been recovered from caves in the Serra da Capivara, state of Piauí. This material is described herein as belonging to a new species, the most hypsodont member of the genus. The specimens also represent an extralimital occurrence of this sigmodontine, as the nearest extant population of Bibimys is ~1,200 km to the south. Because there are few reliable records of extinct small mammals from the Pleistocene–Holocene transition on the South American continent, in describing this new sigmodontine we extend the records of past biodiversity preserved in the Quaternary deposits of tropical South America. This new species likewise highlights that the Serra da Capivara deposits are promising for understanding the evolutionary history of cricetid rodents.

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Late Quaternary Variations in the South American Monsoon System as Inferred by Speleothems—New Perspectives using the SISAL Database

Quaternary ◽

10.3390/quat2010006 ◽

2019 ◽

Vol 2 (1) ◽

pp. 6 ◽

Cited By ~ 10

Author(s):

Michael Deininger ◽

Brittany Marie Ward ◽

Valdir F. Novello ◽

Francisco W. Cruz

Keyword(s):

South America ◽

Late Quaternary ◽

Precipitation Amount ◽

Ice Age ◽

Convergence Zone ◽

South American ◽

The South ◽

South American Monsoon ◽

Monsoon System ◽

South American Monsoon System

Here we present an overview of speleothem δ18O records from South America, most of which are available in the Speleothem Isotopes Synthesis and Analysis (SISAL_v1) database. South American tropical and subtropical speleothem δ18O time series are primarily interpreted to reflect changes in precipitation amount, the amount effect, and consequently history of convection intensity variability of convergence zones such as the Intertropical Convergence Zone (ITCZ) and the South America Monsoon System (SAMS). We investigate past hydroclimate scenarios in South America related to the South American Monsoon System in three different time periods: Late Pleistocene, Holocene, and the last two millennia. Precession driven summertime insolation is the main driver of convective variability over the continent during the last 120 kyrs (from present day to 120 kyrs BP), including the Holocene. However, there is a dipole between speleothem δ18O records from western and eastern South America. Records located in the central region of Brazil are weakly affected by insolation-driven variability, and instead are more susceptible to the variability associated with the South Atlantic Convergence Zone (SACZ). Cold episodic events in the Northern Hemisphere, such as Heinrich and Bond Events, and the Little Ice Age, increase the convective activity of the SAMS, resulting in increased precipitation amount in South America.

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Projected End-of-Century Changes in the South American Monsoon in the CESM Large Ensemble

Journal of Climate ◽

10.1175/jcli-d-19-0645.1 ◽

2020 ◽

Vol 33 (18) ◽

pp. 7859-7874

Author(s):

Ana Claudia Thome Sena ◽

Gudrun Magnusdottir

Keyword(s):

South America ◽

South Atlantic ◽

Northeastern Brazil ◽

Southeastern Brazil ◽

South American ◽

The South ◽

Wet Season ◽

Large Ensemble ◽

South American Monsoon ◽

The Mean

AbstractProjected changes in the South American monsoon system by the end of the twenty-first century are analyzed using the Community Earth System Model Large Ensemble (CESM-LENS). The wet season is shorter in LENS when compared to observations, with the mean onset occurring 19 days later and the mean retreat date 21 days earlier in the season. Despite a precipitation bias, the seasonality of rainfall over South America is reproduced in LENS, as well as the main circulation features associated with the development of the South American monsoon. Both the onset and retreat of the wet season over South America are delayed in the future compared to current climate by 3 and 7 days, respectively, with a slightly longer wet season. Central and southeastern Brazil are projected to get wetter as a result of moisture convergence from the strengthening of the South Atlantic low-level jet and a weaker South Atlantic subtropical high. The Amazon is projected to get drier by the end of the century, negatively affecting rain forest productivity. During the wet season, an increase in the frequency and intensity of extreme precipitation events is found over most of South America, and especially over northeastern and southern Brazil and La Plata. Meanwhile, during the dry season an increase in the maximum number of consecutive dry days is found over northeastern Brazil and the northern Amazon.

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Daily Precipitation Statistics for South America: An Intercomparison between NCEP Reanalyses and Observations

Journal of Hydrometeorology ◽

10.1175/2010jhm1303.1 ◽

2011 ◽

Vol 12 (1) ◽

pp. 101-117 ◽

Cited By ~ 33

Author(s):

Viviane B. S. Silva ◽

Vernon E. Kousky ◽

R. Wayne Higgins

Keyword(s):

South America ◽

Large Scale ◽

Atmospheric Model ◽

Northeastern Brazil ◽

South American ◽

The South ◽

Wet Season ◽

Central Brazil ◽

Monsoon System ◽

Dry Bias

Abstract In this study, the authors document the extent to which the precipitation statistics of the new CFS reanalysis (CFSR) represent an improvement over the earlier reanalyses: the NCEP–NCAR reanalysis (R1) and the NCEP–DOE Second Atmospheric Model Intercomparison Project (AMIP-II) reanalysis (R2). An intercomparison between the CFSR, R1, R2, and observations over South America was made for the period 1979–2006. The CFSR shows notable improvements in the large-scale precipitation patterns compared with the previous reanalyses (R1 and R2). In spite of these improvements, the CFSR has substantial biases in intensity and frequency of occurrence of rainfall events. Over west-central Brazil, the core region of the South American monsoon system (SAMS), the CFSR displays a dry bias during the onset phase of the SAMS wet season and a wet bias during the peak and decay phases of the SAMS wet season. The CFSR also displays a dry bias along the South American coast near the mouth of the Amazon and along the east coast of northeastern Brazil. A wet bias exists in all seasons over southeast Brazil and over the Andes Mountains.

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A mid-Holocene climate reconstruction for eastern South America

Climate of the Past ◽

10.5194/cp-9-2117-2013 ◽

2013 ◽

Vol 9 (5) ◽

pp. 2117-2133 ◽

Cited By ~ 46

Author(s):

L. F. Prado ◽

I. Wainer ◽

C. M. Chiessi ◽

M.-P. Ledru ◽

B. Turcq

Keyword(s):

South America ◽

Late Holocene ◽

Austral Summer ◽

South Atlantic Convergence Zone ◽

Northeastern Brazil ◽

South American ◽

The South ◽

Holocene Climate ◽

Sea Temperature ◽

Summer Insolation

Abstract. The mid-Holocene (6000 calibrated years before present) is a key period in palaeoclimatology because incoming summer insolation was lower than during the late Holocene in the Southern Hemisphere, whereas the opposite happened in the Northern Hemisphere. However, the effects of the decreased austral summer insolation over South American climate have been poorly discussed by palaeodata syntheses. In addition, only a few of the regional studies have characterised the mid-Holocene climate in South America through a multiproxy approach. Here, we present a multiproxy compilation of mid-Holocene palaeoclimate data for eastern South America. We compiled 120 palaeoclimatological datasets, which were published in 84 different papers. The palaeodata analysed here suggest a water deficit scenario in the majority of eastern South America during the mid-Holocene if compared to the late Holocene, with the exception of northeastern Brazil. Low mid-Holocene austral summer insolation caused a reduced land–sea temperature contrast and hence a weakened South American monsoon system circulation. This scenario is represented by a decrease in precipitation over the South Atlantic Convergence Zone area, saltier conditions along the South American continental margin, and lower lake levels.

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Formal recognition of six subordinate taxa within the South American bracken fern, Pteridium esculentum (P. esculentum subsp. arachnoideum s.l.—Dennstaedtiaceae), based on morphology and geography

Phytotaxa ◽

10.11646/phytotaxa.333.1.2 ◽

2018 ◽

Vol 333 (1) ◽

pp. 22 ◽

Cited By ~ 3

Author(s):

PEDRO B. SCHWARTSBURD ◽

AGUSTINA YAÑEZ ◽

JEFFERSON PRADO

Keyword(s):

South America ◽

The Other ◽

Northeastern Brazil ◽

Putative Hybrid ◽

South American ◽

The South ◽

The Third ◽

The Andes ◽

Northern South America ◽

Formal Recognition

Based on the morphological study of ca. 470 specimens and geographical studies, we here propose the recognition of six morphotypes within the South American Pteridium esculentum (= P. arachnoideum s.l., or P. aquilinum var. arachnoideum sensu Tryon, or P. esculentum subsp. arachnoideum sensu Thomson). Three of them are widely distributed and well-defined, and we regard them as subspecies of P. esculentum: P. esculentum subsp. arachnoideum s. str., P. esculentum subsp. campestre, comb. et stat. nov., and P. esculentum subsp. gryphus. The other three are more rare. One of these is a pedomorphic form of P. esculentum subsp. arachnoideum, which we name as P. esculentum subsp. arachnoideum var. paedomorficum, nom. nov. The other is a glabrous form of P. esculentum subsp. gryphus, which we name P. esculentum subsp. gryphus var. harpianum, var. nov. The third is a putative hybrid between P. esculentum subsp. arachnoideum and P. esculentum subsp. campestre. All six taxa are keyed, described, illustrated, mapped, and discussed. Pteridium esculentum subsp. arachnoideum s. str. forms an arc of distribution from eastern, to southern, to western South America (but not occurring west of the Andes); Pteridium esculentum subsp. campestre forms an arc of distribution from northeastern Brazil to northern South America (not occurring west of the Andes either); and P. esculentum subsp. gryphus forms an arc of distribution from western to northern South America (occurring also west of the Andes and in Galapagos). This one is morphologically more similar to the Australasian P. esculentum subsp. esculentum.

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The Influence of Orbital Forcing of Tropical Insolation on the Climate and Isotopic Composition of Precipitation in South America

Journal of Climate ◽

10.1175/jcli-d-14-00639.1 ◽

2015 ◽

Vol 28 (12) ◽

pp. 4841-4862 ◽

Cited By ~ 20

Author(s):

Xiaojuan Liu ◽

David S. Battisti

Keyword(s):

South America ◽

Isotopic Composition ◽

General Circulation ◽

Circulation Model ◽

Ocean Model ◽

Northeastern Brazil ◽

Convergence Zone ◽

South American ◽

The South ◽

Northern Andes

Abstract The δ18O of calcite (δ18Oc) in speleothems from South America is fairly well correlated with austral summer [December–February (DJF)] insolation, indicating the role of orbitally paced changes in insolation in changing the climate of South America. Using an isotope-enabled atmospheric general circulation model (ECHAM4.6) coupled to a slab ocean model, the authors study how orbitally paced variations in insolation change climate and the isotopic composition of precipitation (δ18Op) of South America. Compared with times of high summertime insolation, times of low insolation feature (i) a decrease in precipitation inland of tropical South America as a result of an anomalous cooling of the South American continent and hence a weakening of the South American summer monsoon and (ii) an increase in precipitation in eastern Brazil that is associated with the intensification and southward movement of the Atlantic intertropical convergence zone, which is caused by the strengthening of African winter monsoon that is induced by the anomalous cooling of northern Africa. Finally, reduced DJF insolation over southern Africa causes cooling and the generation of a tropically trapped Rossby wave that intensifies and shifts the South Atlantic convergence zone northward. In times of low insolation, δ18Op increases in the northern Andes and decreases in northeastern Brazil, consistent with the pattern of δ18Oc changes seen in speleothems. Further analysis shows that the decrease in δ18Op in northeastern Brazil is due to change in the intensity of precipitation, while the increase in the northern Andes reflects a change in the seasonality of precipitation and in the isotopic composition of vapor that forms the condensates.

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Impact of enriched analyses on regional numerical forecasts over southeastern South America during SALLJEX

Revista Brasileira de Meteorologia ◽

10.1590/0102-778620100248 ◽

2014 ◽

Vol 29 (3) ◽

pp. 315-330

Author(s):

Yanina García Skabar ◽

Matilde Nicolini

Keyword(s):

Data Assimilation ◽

South America ◽

Atmospheric Modeling ◽

South American ◽

The South ◽

Low Level ◽

Positive Effects ◽

Accumulated Rainfall ◽

Low Level Jet ◽

The Impact

During the warm season 2002-2003, the South American Low-Level Jet Experiment (SALLJEX) was carried out in southeastern South America. Taking advantage of the unique database collected in the region, a set of analyses is generated for the SALLJEX period assimilating all available data. The spatial and temporal resolution of this new set of analyses is higher than that of analyses available up to present for southeastern South America. The aim of this paper is to determine the impact of assimilating data into initial fields on mesoscale forecasts in the region, using the Brazilian Regional Atmospheric Modeling System (BRAMS) with particular emphasis on the South American Low-Level Jet (SALLJ) structure and on rainfall forecasts. For most variables, using analyses with data assimilated as initial fields has positive effects on short term forecast. Such effect is greater in wind variables, but not significant in forecasts longer than 24 hours. In particular, data assimilation does not improve forecasts of 24-hour accumulated rainfall, but it has slight positive effects on accumulated rainfall between 6 and 12 forecast hours. As the main focus is on the representation of the SALLJ, the effect of data assimilation in its forecast was explored. Results show that SALLJ is fairly predictable however assimilating additional observation data has small impact on the forecast of SALLJ timing and intensity. The strength of the SALLJ is underestimated independently of data assimilation. However, Root mean square error (RMSE) and BIAS values reveal the positive effect of data assimilation up to 18-hours forecasts with a greater impact near higher topography.

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Problems and prospects of MERCOSUR as a civilizational political project of South America

Конфликтология / nota bene ◽

10.7256/2454-0617.2020.3.32486 ◽

2020 ◽

pp. 1-8

Author(s):

Mikhail Valer'evich Gorbachev

Keyword(s):

South America ◽

The Political ◽

South American ◽

Core State ◽

The South ◽

Project Approach ◽

Political Project ◽

Key Participants ◽

Further Development

  This article discusses the political projects of civilizational level, which are designed and implemented in South America. The author examines MERCOSUR as the largest regional civilizational political project, its sociocultural foundation and institutional superstructure; functionality of the “core state” in formation and maintenance of the South American civilizational political project; problems of development and future implementation. The article reveals conflict potential of MERCOSUR, as well as sociocultural capabilities for its overcoming by the “core state” of the project. The research was conducted via application of civilizational-project methodology of interpretation of policy, which is based on methodological synthesis of the principles of project approach with provisions of the theory of civilizations. The author was able to determine the value grounds of MERCOSUR, which comprise its sociocultural foundation; identify the countries competing for status of the “core state” within the framework of this project. The nature of commonality between the key participants of the projects is identified. Problems and prospect of further development of MERCOSUR civilizational projects are defined.  

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