Parana Basin Research Articles

First record and extended distribution of Otothyropsis piribebuy (Loricariidae: Hypoptopomatinae) in Brazil

Cascudinhos are a group of small benthic fishes included in the Hypoptopomatinae subfamily, inhabiting small to moderate streams and rivers within the Neotropical region, from Venezuela to Northern Argentina. Until now, Otothyropsis piribebuy originally described from the rio Paraguay basin, in Paraguay, is the only species of the genus not recorded in Brazil. Recent samples in the rio Tererê, rio Paraguay basin, Brazil, revealed a population of Otothyropsis with uncertain taxonomic identity. Therefore, the study aimed to unveil the distribution of Otothyropsis within Brazilian territory. External morphology, osteology, measurements, and counts (plates, teeth, and rays) of these specimens from rio Tererê were compared to data from the original description of O. piribebuy, and also with specimens of O. piribebuy sampled in Paraguayan territory. Observations indicated no differences among the analyzed specimens. Furthermore, a Principal Component Analysis (PCA), carried out using log-transformed measures from Brazilian and Paraguayan specimens, showed no separation of these populations, also indicating that all analyzed specimens pertain to the same species. Based on this, a prediction map of distribution, using Maximum Entropy, was produced. The correct identification of spatial range of occurrence is an essential step to ensure the conservation of species, and the extended distribution of Otothyropsis piribebuy was confirmed, enhancing the list of neotropical fish from Brazil.

Wellbore integrity in a saline aquifer: Experimental steel-cement interface degradation under supercritical CO2 conditions representative of Brazil’s Parana basin

From our work, significant progress has been made in understanding the degradation of cement-casing systems. The CO2 degradation process was evaluated in specimens with a large interfacial defect, such as large annular spaces, voids and/or channels, which may be the result of a poor cementing job. From the experiments showing no interfacial defect, no signs of degradation were observed, while from experiments showing interfacial defect, both the cement and steel undergo significant degradation. In the well casing, the CO2-rich brine affects the steel phase, leaching Fe2+ ions into solution and promoting FeCO3 precipitation on the material surface, while on the cement sheath, two processes are occurring: (i) the portlandite dissolution and (ii) the cement carbonation process. Then, iron (Fe2+) starts to migrate into the cement structure, compromising the material’s self-healing and pore-blocking features, while calcium (Ca2+) starts to compose the corrosion film from the formation of mixed carbonates (FexCayCO3) so reducing the corrosion layer’s protection. Finally, both ions (Ca2+ and Fe2+) become so abundant in the material vicinity that they may form calcium carbonate (CaCO3) on the corrosion layer and iron carbonate (FeCO3) in the cement matrix. Thus, from our results, the degradation mechanisms of the cement-casing system in CO2-rich brine was revised.

Trophic ecology and metabolism of two species of nonnative freshwater stingray (Chondrichthyes: Potamotrygonidae)

The stingrays Potamotrygon amandae and Potamotrygon falkneri are nonnative species established in the Upper Parana basin. Although they are widely distributed, few studies on their diets or respective metabolic responses exist. Therefore, the aim was to evaluate the dietary composition, trophic niche breadth and lipid/protein concentrations in muscle and hepatic tissues of these two species, as well as the interrelationships between them. The individuals were collected in two areas on the Upper Parana River. The stomachs and samples of muscle and liver tissues were taken for analysis. A broad dietary spectrum was observed for both species, along with differences in dietary composition, with a higher consumption of detritus by P. amandae and Baetidae by P. falkneri. No differences were observed in the trophic niche breadth. Regarding the metabolic variables, differences were only found in the hepatic protein, with a higher content observed in P. falkneri. A significant positive correlation was observed between items of animal origin and detritus with muscle protein for this species. This shows that such feeding habits, which are characteristic of a generalist, influenced the metabolism of the species and possibly contributed to the successful adjustment of the species to new habitats in the Upper Parana River.

Length-weight relationship for two species of fish from Upper Paraguay Basin in Mato Grosso do Sul, Brazil

The study of the weight-length relationship of a fish species can be used to address several aspects that involve the distinction of small taxonomic units, providing basic information for the study of species biology, in addition, this relationship can also be used as quantitative indicator of the degree of health or well-being of the species in the environment. The objective of this study was to present unpublished data on the weight-length relationship (LWRs) for two species of fish. The fish were sampled in the months of January and July 2017 and January 2018 in rivers belonging to the Upper Paraná and Upper Paraguay basin along the MS-163, collected through sieves and trawls. 49 individuals were captured, distributed in two orders and two families, being 31 from Hisonotus francirochai and 18 from Roeboides descalvadensis. The results showed that the two species are within the expected for both parameters (a and b), even with a relatively low sample number. In addition, the data this study contribute with biological information for the species studied in this work.

New palynostratigraphic data of the Irati (Assistência Member) and the Corumbataí formations, Paraná Basin, Brazil, and correlation with other south American basins

This research presents the palynostratigraphy of organic-rich shales from the Irati and the Corumbataí formations, Paraná Basin (PB), Southeastern Brazil, as part of an unconventional hydrocarbon source rock and CO2 reservoir assessment study. Thirty-four samples from the Corumbataí Formation and the Assistência Member of the Irati Formation were collected in the states of Goiás (northern border of the PB), São Paulo and Paraná (eastern and southern border of the PB, respectively). The acquired data allowed to establish a comprehensive palynostratigraphic study across the basin where a total of 18 pollen genera (34 pollen species), seven spore genera, four microplankton genera (1 species), and Chlorophyceae algae species where identified. The palynostratigraphic analysis also reveals a clear dominance of bisaccate pollen grains such as Corisaccites alutas, Lueckisporites virkkiae, and Weylandites lucifer. The Lueckisporites virkkiae zone was identified in the upper part of the Irati Formation (Assistência Member) and the lowermost part of the Corumbataí Formation, indicating a Kungurian to Roadian age for this part of the succession. Differences in the Guttulapollenites hannonicus and Tornopollenites toreutos biostratigraphic ranges, recovered in the Corumbataí Formation, suggest an earlier development of these species in the Paraná Basin during the middle Permian. Therefore, to evaluate the differences in the first occurrences of key species within the Paraná Basin, a close palynostratigraphic correlation between the main Guadalupian-Lopingian South American Gondwana basins is tentatively established.

ANÁLISE ESTRUTURAL RÚPTIL NA ZONA DE INFLUÊNCIA DO ARCO DE PONTA GROSSA: ESTUDO DE CASO NA ÁREA DA UHE-MAUÁ-PR

A pesquisa foi realizada no entorno da Usina Hidrelétrica de Mauá (UHE-Mauá), localizada no rio Tibagi, a noroeste do município de Telêmaco Borba divisa com Ortigueira, região central do Estado do Paraná. O local em que a usina está implantada é formado por soleira de diabásio aflorante, pertencente à Formação Serra Geral, intrudida em rochas sedimentares paleozoicas da Bacia do Paraná. No local o controle estrutural se dá em função da intersecção de estruturas regionais como o Arco de Ponta Grossa, localizado entre as Zonas de Falha São Jerônimo-Curiúva e a Zona de Falha Jacutinga. A análise estrutural possibilitou o reconhecimento de falhas, com predomínio de azimute N50-60E em mesoescala. Em fotointerpretação, no entanto, os lineamentos mais marcantes possuem azimute N40-50W. As descontinuidades mapeadas são caracterizadas, principalmente por juntas, falhas e zonas de falhas cataclásticas associadas a regime tectônico transcorrente, por vezes transtensivo com formação de estrutura em flor negativa e falhas oblíquas, identificadas nos sedimentos paleozoicos e nas rochas básicas. Este trabalho aponta a existência de pelo menos dois pulsos de deformação pós-cretácicos, que deformaram a soleira de diabásio e o conjunto de rochas sedimentares encaixantes, alterando o comportamento reológico da rocha e a disposição geométrica final dos grandes planos de fraquezas. O primeiro está ligado a um campo de paleotensão variável entre NNE-SSW e NNW-SSE e o segundo a um campo de paleotensão variável entre WNW-ESSE e ENE-WSW

Chromosome comparison among five species of Neotropical cichlids of Cichlasoma and Gymnogeophagus (Perciformes).

The genera Cichlasoma and Gymnogeophagus belong to the subfamily Cichlinae, the only one in Neotropical cichlids. Cichlasoma dimerus, C. paranaense, C. portalegrense, Gymnogeophagus rhabdotus, and G. lacustris were collected at different points in the Paranapanema and Paraguay basins and the Lagoon of Patos hydrographic system. In addition to conventional analysis, CMA3 fluorochrome staining, and FISH with 18S rDNA probe were performed. All species had a diploid number equal to 48, with interand intraspecific differences in karyotype formulae. All species presented a single AgNOR site, except G. rhabdotus and the C. paranaense population of the Paranapanema River, which revealed more than one pair of nucleolar chromosomes. AgNORs were coincident to 18S rDNA and CMA3. Heterochromatin was distributed in the pericentromeric chromosomal regions and coincident with NORs. For the first time, this work shows cytogenetic data for C. portalegrense, G. lacustris, and G. rhabdotus. Although some results reinforce the idea of conservative chromosome evolution of 2n in Cichlinae, interspecific and populational variations observed confirm that chromosomal rearrangements affect the microstructural karyotype diversification in this group of fish.

Grupo Itararé na região de Itu, estado de São Paulo: intensos processos glaciais erosivos e deposicionais

O Grupo Itararé, Neopaleozoico (Mississippiano-Pennsylvaniano) da Bacia do Paraná, está exposto em grande parte da faixa leste do Estado de São Paulo, predominantemente sobre rochas pré-cambrianas. As áreas aqui designadas Itu e Salto são notáveis pela abundância de registros glaciais, embora de natureza distinta. Este trabalho discute as feições glaciais presentes nessas áreas como subsídio para reconstruções paleoambientais, partindo-se de estudos prévios, e traz observações inéditas de uma frente sedimentar exposta por escavação na Pedreira Colonial. Na área-Salto, o destaque são as evidências de forte ação erosiva glacial, tais como, rochas moutonnées, só encontradas no Brasil nessa região, e pavimentos estriados, associados a tilitos, diamictitos e depósitos aquoso-glaciais que atingem até 8 m de espessura. Na área-Itu, destacam-se os espessos depósitos aquoso-glaciais e, subordinadamente, diamictitos e tilitos que podem alcançar até 300 m de espessura.

Hiperpicnitos (Inunditos) como análogos de reservatórios: um exemplo nos depósitos Gonduânicos Triássicos do Gráben Arroio Moirão, Rio Grande do Sul

Os arenitos associados a modelos episódicos de inundação, como os Inunditos provenientes de fluxos hiperpicnais em corpos de água rasa, podem ser reservatórios de hidrocarbonetos. No entanto, há poucos estudos para entender a arquitetura e heterogeneidade desses modelos, o que resulta em dificuldades para exploração e explotação desses reservatórios. O presente trabalho visa à análise de pacotes triássicos da Bacia do Paraná pertencentes à Formação Santa Maria, que ocorrem como fragmentos isolados sobre o Escudo Sul-Rio-Grandense na região do Gráben Arroio Moirão (Rio Grande do Sul). Para tanto, fez-se um estudo comparativo de modelos de inundação e como metodologia de obtenção de dados utilizou-se mapeamento sistemático, análise de heterogeneidade de fácies e estratigrafia de sequências, que incluem levantamento de perfis colunares, identificação de associações e sucessões de fácies e superfícies-chave. Secundariamente, algumas análises petrográficas foram realizadas. Foi possível delimitar os principais depósitos de arenitos, dos quais predominam geometria tabular, grãos mal selecionados e alguma matriz argilosa. Distinguiram-se cinco ciclos deposicionais granodecrescentes ascendentes, limitados na base e no topo por superfícies erosivas, que marcam heterogeneidades recorrentes. As fácies-reservatório são subarcósios, de matriz argilosa com agregados de caulinita, porosidade intergranular e shrinkage. Identificaram-se potenciais fácies-reservatório constituídas de arenitos grossos a conglomeráticos, com estratificações cruzada tangencial e plano-paralela. A integração dos dados resultou na elaboração de um modelo de variação lateral e vertical de fácies de hiperpicnitos lacustres, como um potencial modelo análogo de reservatório do tipo compartimentado. Esses resultados possibilitam prospectar outros depósitos arenosos dessa unidade estratigráfica da Bacia do Paraná, para fins de dimensionar regionalmente o análogo de reservatório.

Effects of Climate and Land-Cover Changes on Soil Erosion in Brazilian Pantanal

The Pantanal biome integrates the lowlands of the Upper Paraguay Basin (UPB), which is hydrologically connected to the biomes of the Cerrado and Amazon (the highlands of the UPB). The effects of recent land-cover and land-use (LCLU) changes in the highlands, combined with climate change, are still poorly understood in this region. Here, we investigate the effects of soil erosion in the Brazilian Pantanal under climate and LCLU changes by combining different scenarios of projected rainfall erosivity and land-cover management. We compute the average annual soil erosion for the baseline (2012) and projected scenarios for 2020, 2035, and 2050. For the worst scenario, we noted an increase in soil loss of up to 100% from 2012 to 2050, associated with cropland expansion in some parts of the highlands. Furthermore, for the same period, our results indicated an increase of 20 to 40% in soil loss in parts of the Pantanal biome, which was associated with farmland increase (mainly for livestock) in the lowlands. Therefore, to ensure water, food, energy, and ecosystem service security over the next decades in the whole UPB, robust and comprehensive planning measures need to be developed, especially for the most impacted areas found in our study.

Distinct deep subsurface microbial communities in two sandstone units separated by a mudstone layer

Deep subsurface microbial communities are more abundant in coarse-grained sedimentary rocks such as sandstones than in fine-grained mudstones. The low porosity and low permeability of mudstones are believed to restrict microbial life. Then, it is expected that distinct, isolated microbial communities may form in sandstones separated by mudstones. In this context, the connectivity between microbial communities in different sandstone units can be investigated to infer evolutionary patterns of diversification in space-time, which may potentially contribute with relevant data for analyses of hydraulic connectivity and stratigraphic correlation. In this work, we used high throughput DNA sequencing of a ribosomal 16S gene fragment to characterize the prokaryotic communities found in Permian sandstone samples of the same core that are separated by one mudstone interval, in the Charqueadas coal field, Parana Basin (Southern Brazil). Our samples were collected at ∼300 m deep, in porous sandstones separated by a thick mudstone package. Differences in the bacterial community structure between samples were observed for the classified OTUs, from phylum to genus. Molecular biology might be further applied as a possible tool to help to understand the spatial and temporal distribution of depositional facies, and the efficiency of low permeability rocks to compartmentalize reservoirs. Ongoing studies aim to extend the present investigation into further analyses regarding lateral changes in microbial communities present in the same sandstone units.

A new species of miniature Characidium (Characiformes: Crenuchidae) from the upper Rio Paraguay basin, Mato Grosso state, Brazil.

A new miniature species of Characidium is described from the upper Rio Paraguay basin, Brazil. The new species can be diagnosed from all congeners by the presence of a dark-brown humeral blotch, vertically elongated (spanning 5 to 7 horizontal scale rows), with the shape of an upside-down acute triangle. Additionally, it can be diagnosed by a short lateral line (6 to 8 perforated scales), the absence of a conspicuous peduncular blotch, a lower number of principal caudal-fin rays (14-16) and by absence of the adipose fin. The new species is the smallest species of the genus; the largest specimen was 19.3 mm standard length.

Hydrochemical and contamination evolution of Rio Bonito aquifer in the Carboniferous region, Paraná Basin, Brazil

Groundwater is an essential natural reserve of fresh water in the world. However, population and economic growth in many countries has caused the contamination of many aquifers. Water crises make significant any study of the Parana Basin aquifers, composed of several geological formations with high capacity of storage and transmission of water. In this context, Rio Bonito aquifer is in part located in the Carboniferous Region of Santa Catarina state (Brazil) and in the Ararangua Hydrographic Basin. The carboniferous region is known for coal mining and minimal care for the environment which led to damaging consequences. In this study, the interpretation of chemical data from nine wells monitored by ‘Grupo Tecnico de Assessoramento’ (GTA, Relatorio de Monitoramento dos Indicadores Ambientais (Internal technical reports referent the years 2006–2018), vol 1. Acao Civil Publica n. 93.8000.533-4. Processo de cumprimento de sentenca n. 2000.72.04.002543-9. Criciuma, Brasil, 2018) was performed with binary variation diagrams, photo interpretation and comparison with local geology. This resulted in the identification of four groundwater groups with different hydrogeochemical characteristics, due to processes of water/rock interaction and contamination by the coal mines. The petrographic analysis defined that the sandstones from top coal layer of Rio Bonito aquifer is of the fractured type. The results indicate that the Rio Bonito aquifer in the studied region is contaminated by coal mining with high levels in limited areas, but only in one well. Groundwater quality is monitored in the Rio Bonito aquifer, which is very important for the management of water use and mitigation of existing contamination, but also to prevent contamination of other areas.

Total Organic Carbon, Porosity and Permeability Correlation: A Tool for Carbon Dioxide Storage Potential Evaluation in Irati Formation of the Parana Basin, Brazil

Total Organic Carbon, Porosity and Permeability Correlation: A Tool for Carbon Dioxide Storage Potential Evaluation in Irati Formation of the Parana Basin, Brazil

WATER BALANCE BASED ON REMOTE SENSING DATA IN PANTANAL

Water storage in a drainage basin determines its water security. The quantity of water retained in the watershed can be measured by means of the water balance calculation. This balance can be defined by the input of water subtracted from the outputs. However, for the Pantanal, the measurements of water inlet and outlet are expensive, which makes the use of remote sensing data a high impact tool with clear socioeconomic advantages. Studies of water availability with orbital sensors are relatively scarce in the Upper Paraguay Basin (BAP). This work is an attempt to estimate the BAP water balance using rainfall and evapotranspiration remote sensing data from the Tropical Rainfall Measuring Mission (TRMM) and the MODIS Global Evapotranspiration Project (MOD16), respectively. The results indicate that BAP had an annual surplus of water between 2000 and 2014, though water parameters seem weakly correlated at annual basis. However, there may be atmospheric-climatic phenomena that maximize the correlation between the hydrological parameters and the temperature anomaly with delays of 2 to 5 years, suggesting lagged teleconnections with QBO and ENSO.

REMOTE SENSING OF WATER BALANCE IN PANTANAL

Pantanal, located in the Upper Paraguay basin, is the world’s largest tropical wetland. The maintenance of this ecosystem depends on the water balance since precipitation is seasonal and high losses of water occur due to the high evapotranspiration. Water balance assessment using in situ data is still a challenge due to the large extension of the area and the complexity to be represented. In this study, the water balance in the Upper Paraguay basin was investigated based on hydrological variables derived from remote sensing data. Precipitation, evapotranspiration, and water storage change data were estimated with accuracy by the water balance, but the same was not possible for the discharge. However, high uncertainties in the estimates were verified, mainly during the rainy season. The remote sensing data allowed the identification of the seasonality of hydrological variables in the Pantanal system and in the different regions of the basin: Chaco, Pantanal and Planalto. Water deficit in the basin was observed from March/April to September as well as a positive water balance due to precipitation during the rest of the year. The spatial analysis of the basin showed that in the northern region, the precipitation, the evapotranspiration, and the water storage variation are higher than in the southern region. Results demonstrated that remote sensing data can help in the comprehension of hydrological systems operation, especially in large wetland regions.

LAND USE AND LAND COVER DYNAMICS IN MUNICIPALITIES OF THE UPPER PARAGUAY RIVER BASIN BASED ON THE GEOPORTAL TERRACLASS

The Upper Paraguay Basin (hereafter, by the Portuguese acronym BAP) has great ecological importance to Brazil since it includes the Pantanal, one of the largest wetlands in the world. Monitoring the land use and the land cover (LULC) is strategic not only for the floodplain of BAP but also for its plateau since the floods in Pantanal are affected by the actions conducted in its surroundings. Part of the BAP area placed within the State of Mato Grosso is mapped by the TerraClass Amazon Project and, therefore, the LULC dynamics in these localities can be assessed through these official data. The aim of this study was to analyze the LULC dynamics in three municipalities in the State of Mato Grosso, Brazil, using the geospatial tools provided by a Web-GIS based on data from the TerraClass Amazon Project. The results showed that in the municipalities of Denise and Barra do Bugres, between 2004 and 2014, there was a significant increase in the areas of Semi-Perennial Agriculture mainly due to the conversion from Cultivated Herbaceous Pasture. In the municipality of Santo Afonso, the class that presented the highest growth rate in the period was Annual Agriculture, with most of the areas being converted from pasture areas. The results highlight the processes of territorial dynamics that took place in the studied municipalities. The conversion from cultivated pasturelands to croplands (annual or semi-perennial agriculture) has been the main responsible aspect for the expansion of the agricultural activity in these municipalities.

First Fossil Wood from the Northern Pampa (Upper Pleistocene), Santa Fe Province, Argentina

The present work introduces the first anatomical and systematic study of a fossil wood found in the Northern Pampa. The diagnostic anatomical features of the fossil wood are common in the Proteaceae family and Roupala genus. This fossil wood can be included within the organ genus Scalarixylon, Pujana. This family is considered a relict group from Gondwana because of its disjunct modern distribution in Australia, Africa, Central and South America, and limited places in Asia and the Pacific Isla. This finding is particularly significant for future paleobiogeography interpretations about this region and for the occurrence of Proteaceae fossil in the Parana Basin over the Pleistocene.

Facies, petrophysical and geochemical properties of gravity-flow deposits in reservoir analogs from the Itararé Group (late Carboniferous), Paraná Basin, Brazil

Abstract Since many reservoirs do not allow direct observation due to their depth and/or difficulty of sampling, studies of analogs have been commonly used as a tool to understand the spatial distribution of reservoir properties. The Parana Basin is 1.6 million km2 large and has two known petroleum systems. However, there are only 124 irregularly distributed wells drilled in the basin, among which 22 contain gas or oil shows and 10 have sub commercial accumulations. The Permo-Carboniferous Itarare Group, due to the exploration history, is the best exploratory target in the basin because it has thick intervals of sandstones with moderate to good reservoir quality and also because it often lies directly on gas-prone source rocks of the Devonian Ponta Grossa Formation. In order to increase knowledge about Itarare Group reservoirs, as well as to better understand its heterogeneities, this study aims to integrate petrophysical data with facies and facies associations using both outcrop and cores from shallow wells in southeastern Parana Basin. By doing this it is expected to fill a gap of quantitative data in previous studies on reservoir analogs in the Itarare Group. Cores and outcrops were analyzed in sandstones in order to integrate surface and subsurface data, and to understand the lateral continuity according to stratigraphic correlations. Equipment such as gamma-ray spectrometer, portable x-ray fluorescence, and a minipermeameter were used for the acquisition of quantitative data. Sedimentological description of cores and outcrops as well as thin section description were also carried out. The facies with the greatest reservoir potential are medium to fine-grained, massive (Sm) and normally-graded (Sg) sandstones. In one outcrop locality (Rio dos Cedros), the Sg facies presents the best reservoir properties such as secondary porosity of 32% and average permeability of 1439 mD. The geochemical data allowed evaluating the gamma-ray variation in relation to chemical elements, such as iron oxide. In outcrop, API radiation is higher in relation to the cores, as well as Al2O3 and Fe2O3. These values are related to the large amount of intraclasts and cementation by iron oxides-hydroxides. Despite in the great amount of iron presents in the Rio dos Cedros samples, the porosity is mainly secondary, generated by the feldspars dissolution. The correlation between the cores and outcrops allowed the evaluation of the influences of mass transport deposits in the petrophysical properties of sandstones. In cores, sandstones interbedded with these deposits have high permeability, but it is not possible to evaluate its lateral continuity. In outcrops it was possible to observe that these deposits affect lateral continuity, permeability and porosity. We conclude that the best reservoir facies in the Itarare Group will be associated with sites within the basin that are away from the slope region and the influence of mass-transport processes.

LOS MOLUSCOS FLUVIALES EN LA SUBSISTENCIA DE LOS GRUPOS CAZADORES-RECOLECTORES DEL HUMEDAL DEL PARANÁ INFERIOR.

En este trabajo se discute el rol de los moluscos fluviales en la subsistencia de los grupos cazadores-recolectores del tramo final de la cuenca del río Paraná, especialmente de Diplodon (Rhipidodonta) variabilis. Se analiza su disponibilidad ambiental, la distribución de tallas en un banco actual y las relaciones alométricas entre los pesos del tejido blando y del exoesqueleto. Paralelamente, se describe la posición de este bivalvo dentro del ranking de las presas locales, y su incorporación en el proceso regional de diversificación e intensificación de la subsistencia durante el Holoceno tardío. Luego, con los resultados obtenidos, se analizan los conjuntos arqueomalacológicos recuperados en los sitios Punta Canal (900 ± 80 años 14C AP), La Bellaca sitio 1 (1110 ± 70 años 14C AP) y Cerro Lutz (730 ± 70 / 953 ± 47 años 14C AP), donde se discuten las actividades de recolección, la selectividad dimensional y el aporte neto de alimento. Finalmente, se analizan las señales isotópicas transferidas a los humanos relacionados con la ingesta de esta especie.