Laguna De Los Research Articles

Threatened aquatic Andean frogs and mining activity in the Lithium Triangle of South America: Can both coexist?

Abstract The aquatic Andean frogs of genus Telmatobius are one of the most threatened amphibian taxa, with many species having suffered drastic declines and even possible extinction. The Laguna de los Pozuelos' rusted frog Telmatobius rubigo is a fully aquatic species that inhabits lotic systems in the Argentinean vertex of the Lithium Triangle of South America. This study estimated the environmental suitability of an area and geographical distribution of T. rubigo through an ecological niche model. This study also aimed to assess the possible extent of impacts related to mining operations on this threatened species. The ecological niche model of T. rubigo was obtained using specific freshwater habitat variables and the MaxEnt algorithm. The possible extent of impacts related to mining operations was evaluated by overlaying the mining tenure and the estimated distribution of T. rubigo resulting from the model. According to the ecological niche models, T. rubigo could occupy 2,001 km2 in four Argentine basins and three hydrographical units of southern Bolivia and is unlikely to occur in northern Chile. Five environmental variables had the highest contribution to the best selected model: shrub coverture, soil pH, soil organic carbon, and two variables related to the upstream air temperature. The suitable area for T. rubigo overlaps with mining operations by 61.8%. We advise the local communities, governmental environmental agencies, mining companies, and environmental assessors to consider the presence of threatened Telmatobius species in areas subject to mining to protect them and their environment. We encourage incorporating the aquatic Andean frogs as key species into management, environmental monitoring, and remediation plans.

Multi-year assessment of variability in spatial and social relationships in a subterranean rodent, the highland tuco-tuco (Ctenomys opimus)

In some species, populations routinely contain a mixture of lone and group-living individuals. Such facultative sociality may reflect individual differences in behavior as well as adaptive responses to variation in local environmental conditions. To explore interactions between individual- and population-level variabilities in behavior in a species provisionally described as facultatively social, we examined spatial and social relationships within a population of highland tuco-tucos (Ctenomys opimus) at Laguna de los Pozuelos, Jujuy Province, Argentina. Using data collected over 5 consecutive years, we sought to (1) confirm the regular occurrence of both lone and group-living individuals and (2) characterize the temporal consistency of individual social relationships. Our analyses revealed that although the study population typically contained lone as well as group-living animals, individual spatial and social relationships varied markedly over time. Specifically, the extent to which individuals remained resident in the same location across years varied, as did the number of conspecifics with which an animal lived, with an overall tendency for individuals to live in larger groups over successive years. Collectively, these analyses indicate that population-level patterns of behavior in C. opimus are consistent with facultative sociality but that this variation does not arise due to persistent differences in individual behavior (i.e., living alone versus with conspecifics). Instead, based on changes in spatial and social relationships across years, we suggest that variation in the tendency to live in groups is shaped primarily by local ecological and demographic conditions.Significance statementCharacterizing variation in conspecific relationships is critical to understanding the adaptive bases for social behavior. Using data collected over 5 successive years, we examined temporal variation in spatial and social relationships within a population of highland tuco-tucos (C. opimus) from northern Argentina. In addition to providing the first multi-year assessment of the behavior and demography of this species, our analyses generate important insights into relationships between individual behavior and population-level patterns of social organization. The behavioral variability evident in our study population suggests that C. opimus is an ideal system in which to explore the causes and consequences of individual differences in social behavior.

Facultative sociality in a subterranean rodent, the highland tuco-tuco (Ctenomys opimus)

AbstractUnderstanding why social relationships vary among conspecifics is central to studies of animal behaviour. For many species, patterns of space use provide important insights into social behaviour. To characterize the social organization of the highland tuco-tuco (Ctenomys opimus), we used visual observations and radiotelemetry to quantify spatial relationships among adults in a population at Laguna de los Pozuelos, Jujuy Province, Argentina. Specifically, we sought to confirm anecdotal reports that these subterranean rodents are social, meaning that adults share burrow systems and nest sites. Our data indicate that the animals live in spatially distinct groups, although the number of individuals per group varies markedly. Although these relationships were robust with regard to location (above vs. below ground) and type of data (visual vs. telemetry), some groups identified during the daytime fissioned during the night. We suggest that the population of C. opimus at Pozuelos is facultatively social, meaning that individuals display predictable, adaptive differences in social relationships with conspecifics. More generally, our findings add to the growing number of subterranean species of rodents recognized as social, thereby generating new opportunities for comparative studies of these animals aimed at assessing the causes and consequences of variation in social organization.

2,100 years of human adaptation to climate change in the High Andes.

Humid montane forests are challenging environments for human habitation. We used high-resolution fossil pollen, charcoal, diatom and sediment chemistry data from the iconic archaeological setting of Laguna de los Condores, Peru to reconstruct changing land uses and climates in a forested Andean valley. Forest clearance and maize cultivation were initiated during periods of drought, with periods of forest recovery occurring during wetter conditions. Between AD 800 and 1000 forest regrowth was evident, but this trend was reversed between AD 1000 and 1200 as drier conditions coincided with renewed land clearance, the establishment of a permanent village and the use of cliffs overlooking the lake as a burial site. By AD 1230 forests had regrown in the valley and maize cultivation was greatly reduced. An elevational transect investigating regional patterns showed a parallel, but earlier, history of reduced maize cultivation and forest regeneration at mid-elevation. However, a lowland site showed continuous maize agriculture until European conquest but very little subsequent change in forest cover. Divergent, climate-sensitive landscape histories do not support categorical assessments that forest regrowth and peak carbon sequestration coincided with European arrival.

Reflectance transformation imaging. First applications in cultural heritage in Argentina

In this article we present two cases of Reflectance Transformation Imaging (RTI) applications. This computational photographic method, based on the acquisition and processing of images, helps to reveal details of the surface of an object that are not visible by direct observation or by standard photography. In the first case, RTI was applied to faunal bone remains that were found during archaeological rescue tasks in Laguna de los Pampas, Province of Buenos Aires. The RTI analysis of these remains with traces of manufacturing and/or use has increased the knowledge of bone technology for this area. In the other case, RTI was applied to a funerary column of the Recoleta Cemetery, located in the city of Buenos Aires, in order to recover the low relief recorded on it. In this way it was possible to rescue the historical and heritage value of the vault.

Transporting rocks to an empty environment of lithic raw materials. The case of the Central Pampean Dunefields (Argentina)

The main objective of this paper is to explore the reasons for hunter-gatherer raw material transport towards the Central Pampean Dunefields (Pampa grasslands of Argentina); a landscape lacking lithic raw materials. For this purpose, we present macroscopic characterizations of stone tools and analyze different production and use strategies from four Holocene stratified sites: La Susana 1, Laguna de los Pampas, Laguna Cabeza de Buey 2, and Huencú Nazar. In these sites, the lithic assemblages are formed mainly by orthoquartzite and chert from the Tandilia Range (southeast), followed by lower frequencies of other non-local lithic raw materials (silicified dolomite, silicified limestone, silex, sandstone, metaquartzite, chalcedony, ryolite, obsidian, among others), which came from diverse vectors of provenance (south, west, southeast, southwest, and northwest). We conclude that distances from the sites to the area of lithic acquisition was not the main factor in the use of certain stones in the Central Pampean Dunefields. Other variables have a more prominent role, such as the qualities of knapping rocks, the access to the quarries, the predominant direction of human mobility, and the social interactions between hunter-gatherer groups that occupied different territories of the Pampa grasslands during the Middle and Late Holocene.

Study of a New Population of the Argentinian Endemic Species Riella choconensis Hässel (Riellaceae, Marchantiophyta) Reveals a Novel Anatomical Structure of the Female Involucre in Riella

A new population of the Argentinian endemic Riella choconensis Hassel (Riellaceae, Marchantiophyta) was discovered from a culture of sediments from the Laguna de los Juncos (Rio Negro province, Argentina). This species was known previously from two nearby collections, made in 1984, in the type locality at the Ramos Mexia reservoir (Neuquen province) and was not recorded since. Fresh material from the new population enabled detailed morphological analyses, which are extensively described here, illustrated and compared to type material of the species. Based on the smooth female involucre, the species belongs to subgenus Riella Mont. However, cross-sections of this structure showed that R. choconensis has bistratose involucre walls, contrasting with the unistratose female involucres of all other species in the genus. The updated morphological data are integrated into a new key to the identification of the American species of Riella.

Oral pathology patterns in late farmers of the Central Andes: A comparative perspective between coastal and highland populations

Aiming at future comparisons with earlier hunter-gatherers or transitional populations, this paper intends to characterize and describe the oral pathology pattern of late agriculturalists from Central Andes dating to the Late Intermediate Period (LIP) and Inca periods (1000–1532 CE), and identify differences and/or similarities between coastal and highland populations. Although the botanical inventories of the LIP suggest carbohydrate-rich diets and similar components, it has been hypothesized that coastal and highland populations had, nevertheless, substantially different oral pathology patterns. We evaluated 14 indicators of oral pathology from Los Pinos (n=200) and Armatambo (n=25) sites in the Central Coast and two chronological phases from Laguna de los Cóndores site (LC-Inca, n=23; and LC-LIP, n=55), in the Peruvian northern highlands. The results showed a recurrent pattern of oral pathologies characterized by cervical caries (above 30%), extra-occlusal caries (above 60%), high rates of gross-gross caries, high frequency of ante mortem tooth loss, and signals of periodontal disease among these four populations. The diets of the coast were slightly more abrasive than those of the highlands. Oral pathology patterns were compatible with a slightly more cariogenic diet in the coast than in the highlands. In all four populations, those patterns were modulated by other common factors such as consumption of fermented drinks (maize beer – chicha) and the coca leaf chewing habit.

OSTRACODE BIOFACIES AND SHELL CHEMISTRY REVEAL QUATERNARY AQUATIC TRANSITIONS IN THE POZUELOS BASIN (ARGENTINA)

Here we present the first use of calcareous microfossils to examine the late Quaternary paleoecology of the endorheic Pozuelos Basin (Argentina). Modern deposition in the basin centers on Laguna de los Pozuelos (LP), a shallow playa-lake that is fed by axial rivers and groundwater and dominantly accumulates siliciclastic sediments. Today, the distribution of limnocytherid and cypridoidean ostracodes across southern LP is strongly influenced by distance to the Rio Cincel delta, whereas the northern end of the playa-lake is characterized by a paucity of ostracodes due to frequent sub-aerial exposure. Ten ostracode biofacies define a sediment core retrieved from LP, which reveal progressive changes in aquatic environments that varied in salinity, depth, and proximity to deltas over the late Pleistocene. Closed lakes occupied the basin from ∼ 37.6–30.7 ka, ∼ 28.0–25.0 ka, and ∼ 23.0–16.6 ka, whereas saline wetlands occurred when these lakes contracted. Extant LP has no analog in the late Pleistocene record; it formed after ∼ 7.2 ka, following a hiatus that removed the Pleistocene–Holocene transition. Paleoecological evidence indicates that the core site was influenced by deltaic inflows from the eastern basin margin until ∼ 24.3 ka, an area where today dry alluvial fans are found. Reorganization of the watershed by normal faulting, most likely at ∼ 18.0 ka, appears to have reduced the influence of these deltaic inflows. Extensional neotectonics, perhaps induced by incorporation of the Pozuelos Basin into the Andean hinterland, is a mechanism that along with tropical climate change is potentially important to water balance and ecology in high-altitude convergent orogenic basins.

A glimpse to Laguna de los Cisnes, a field laboratory and natural monument in the Chilean Patagonia

Laguna de los Cisnes (53°15’S) is a remote and unusual salty lagoon located in the Chilean Patagonia, declared natural monument to protect bird diversity in the area, which could also serve as a natural laboratory to monitor climate change. This study reports basic water, sediment and plankton characteristics observed during a summer (December) sampling, when the lagoon was hypersaline (51 g L -1 ), cold (9°C) and eutrophic, according to the high concentrations of phosphorous (0.30 ± 0.73 mg L -1 ), nitrate (0.66 ± 0.14 mg L -1 ) and chlorophyll-a (44.25 ± 2.52 µg L -1 ). The microalgae Spirogyra sp. and the micro-crustacean Artemia are predominating plankton. Results are discussed in the context of the climatic conditions affecting this lagoon year-round. Normal 0 21 false false false ES-CL X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;}

A 2000-year history of disturbance and recovery at a sacred site in Peru’s northeastern cloud forest

The last 2000 years in the tropical Andes was both a time of major pre-Hispanic and Hispanic period cultural developments, and increased climate variability. From c. AD 1000, Andean societies underwent significant transformation and many sites previously integrated under imperial Wari hegemony were abandoned. It has been argued that this sociopolitical reorganization was, in part, a response to the heightened climate variability of the late-Holocene. Here, we present a 2000-year diatom record from the cloud forest setting of Laguna de los Condores, in the Peruvian Andes. Cliff tombs overlooking the lake and a nearby abandoned village form one of the most important archaeological complexes in the Peruvian Chachapoyas region. The presence of diatoms that indicate high productivity (e.g. Planothidium frequentissimum and Amphora pediculus) from as early as 2000 cal. yr BP suggest the lake was impacted by human activity predating the construction of monumental architecture and the regional Chachapoya cultural identity. The diatom fauna is consistent with sediment geochemical evidence that suggests high terrigenous input during the same period that would indicate that the surrounding catchment was disturbed. After c. AD 900 (1050 cal. yr BP), the diatom assemblage becomes dominated by species more indicative of a less productive system, coincident with a declining sedimentation rate, and a decrease in total biogenic silica: conditions that persist to modern times. The transition from a lake with high productivity receiving high erosional input to a less productive more stable system is contemporaneous with an increase in archaeologically documented mortuary and settlement activity. This period of declining terrigenous input is at odds with regional climate, which suggests a wetter than average period. Our data suggest the occupants of Laguna de los Condores changed their land use practices, as the region became wetter, and, in so doing, reduced erosion around the lake.

Estudio de la comunidad de oribátidos (Acari: Oribatida) en dos parches de tala (Celtis ehrenbergiana) del sudeste bonaerense

Study of the oribatid mite (Acari: Oribatida) community from two patches of tala (Celtis ehrenbergiana) from the southern of Buenos Aires. “Talares” are xeric forests located along the coast of Buenos Aires province, Argentina. Since >400 years ago, they have been subject of a severe degradation, resulting in a fragmentary landscape of forest patches surrounded by a grassland matrix. The aims of this study were: a) to enhance the knowledge of oribatid mites in the talares, and b) to analyze the effect of habitat fragmentation on diversity, richness, abundance and structure of the oribatid mite community. I analyzed oribatids in three sites: two different-size close forest patches (big: Gr, small: Ch) and the surrounded grassland matrix (Ma) in Laguna de los Padres reserve, Mar del Plata. A total of 51 species of oribatids were identified, with similar values of richness in all sites. Oppiidae y Scheloribatidae were the families with more species. Diversity (H’) was greater in the forest patches (Gr=1.58; Ch=1.59) than in the matrix (Ma=0.91). Density of oribatid mites was higher in Gr (36500 individuals/m2); in Ch and Ma, densities were 50% and 75% lower. This global difference is a consequence of reduced population sizes in most species. According to seasonal variations, in Gr there were more “ubiquitous” species (20) than in Ch y Ma (10). Summarizing, the community of oribatid mites were primarily conditioned by the type of environment (grassland vs. forest), with similar distribution patterns of species but with a marked seasonality in the grassland matrix. Among forest patches, area did affect oribatid mites density through a reduction in most population sizes. The evaluation of the fragility of these populations could be a starting point to undertake conservation programs.

Late Quaternary lacustrine ostracods (Ostracoda, Crustacea) and charophytes (Charophyta, Charales) from the Puna Plateau, Argentina

Relatively little is known about the recent palaeontological records of the high-altitude closed basin lakes of the Central Andes, but a great need exists to remedy this knowledge gap if microfossils are to be used to infer climatic and ecological transitions from lake sediment cores. Here, eight species of non-marine ostracods and two calcareous algae are recorded from modern sediments and late Quaternary strata from Laguna de los Pozuelos, Jujuy Province, northwestern Argentina. Four species, Limnocythere alexanderi, Limnocythere foresteri, Limnocythere lysandrosi and Limnocythere ruipunctifinalis , are described as new species. Limnocythere titicaca Lerner-Seggev, 1973 has only been recorded in Lake Titicaca prior to this study and this is the first time the species is recognized outside of Bolivia. The cypridoideans Ilyocypris ramirezi Cusminsky & Whatley, 1996, Eucypris virgata Cusminsky & Whatley, 1996 and Chlamydotheca pseudobrasiliensis Martens & Behen 1994 are known species that are rare in the stratigraphic sequence in core LP06-6A. Also, the gyrogonites of two well-known species of Charophyta, Chara filiformis Hertzsch and Chara vulgaris Linnaeus, are occasionally present in the sediment from Laguna de los Pozuelos. The results provide a new vehicle for clarifying the Quaternary palaeohydrological history of the Pozuelos Basin, which is a RAMSAR wetland that is likely to be sensitive to global environmental change.

Interacción Sociedad y Medio Ambiente. El Entorno De La Laguna de los Tollos (Andalucía Occidental), Siglos XIII al XV

Environment of the Laguna de los Tollos is studied between 13th and 15th Centuries. The research, which aims to analyse the interaction environment-society, is part of a project that will deepen the knowledge of wetlands in this geographical area. In these ecosystems rural communities took advantage with their farmland for hunting, herding, fishing and gathering resources in riparian areas. The chosen chronological period includes a wide range of changes that had a direct impact on the management and organization of rural landscapes.

Olmec crayfish farming

The Olmecs of Early and Middle Formative times were responsible for constructing the earliest civilization in Mesoamerica. They influenced later Mesoamerican civilizations in ways that can be seen in iconography, calendrics, epigraphy, town planning, architecture, and loan words, as well as in myriad ways that are not so easily traceable. Major sites, such as San Lorenzo, La Venta, Laguna de los Cerros, Chalcatzingo, and Teopantecuanitlan were actively occupied for varying periods between approximately 1400 and 300 B.C. Although Teopantecuanitlan is located in Guerrero and Chalcatzingo is in Morelos, what is known as the Olmec heartland is focused on the northern part of the Isthmus of Tehuantepec, in southern Veracruz and western Tabasco (Fig. 1). Olmecs are believed by some scholars to have spoken a Mayan language. Others, basing their opinions on language distribution, loan words, and physical types in local populations, think that the Olmecs spoke a Mixe-Zoquean language.

Playa‐lake sedimentation and organic matter accumulation in an Andean piggyback basin: the recent record from the Cuenca de Pozuelos, North‐west Argentina

AbstractExpansive playa‐lake systems situated in high‐altitude piggyback basins are important and conspicuous components of both modern and ancient cordilleran orogenic systems. Extant playa lakes provide vital habitat for numerous endemic species, whereas sediments from these deposystems may record signals of climate change or develop natural resources over geological time. Laguna de los Pozuelos (North‐west Argentina) provides the opportunity for an actualistic sedimentological and geochemical assessment of a piggyback basin playa lake in an area of critical interest for understanding Quaternary palaeoclimate dynamics. Silty clays and diatom ooze are the dominant playa‐lake centre microfacies, with concentrations of total organic carbon and biogenic silica commonly exceeding 1·5 wt% in this sub‐environment. Elemental and stable isotopic analyses point to a mixed organic matter composition in the playa‐lake centre, with substantial contributions from algae and transported aquatic macrophytes. Bulk sediment and organic mass accumulation rates in the southern playa‐lake centre approach 0·22 g cm−2 year−1 and 2·89 mg cm−2 year−1, respectively, indicating moderately rapid deposition with negligible deflation over historic time. Playa margin facies contain higher percentages of fragmented biogenic carbonate (ostracods and charophytes) and inorganically precipitated aragonite crusts due to seasonal pumping and evaporation of ground water. Organic matter accumulation is limited along these heavily bioturbated wet and dry mud flats. Fluvial–lacustrine transitional environments, which are key waterbird habitats, are either silty terminal splay (northern axis) or sandy deltas (southern axis) containing highly oxidized and partially allochthonous organic matter. Modern analogue data from Laguna de los Pozuelos provide key insights for: (i) environmental reconstructions of ancient lake sequences; and (ii) improving facies models for piggyback basins.

Control of elmleaf blackberry invasion in a natural reserve in Argentina

The invasion of exotic plants is a serious problem for natural communities. The efficacy of the combination of physical and chemical methods to control blackberry invasion and their impact on native plant communities were evaluated. The experiment was conducted at Laguna de los Padres Reserve, located in the southeast of Buenos Aires Province, Argentina. In winter 2006, two areas were bulldozed. In one of them, blackberry plants were cut and left on the ground. In the other, plants were cut and the upper part of the soil was removed, digging out the crowns and roots. After regrowth, two chemical treatments were applied: glyphosate 2% and 4%, leaving plots without herbicide. The percentages of cover of blackberry and each one of the species growing were recorded. Measurements started in October 2006 and were made twice a month during spring–autumn 2006–2007 and 2007–2008. The methods evaluated in this study controlled blackberry and allowed the growth of other species. Glyphosate was more efficient if applied in late summer–early autumn. No differences between herbicide doses were found. The most intense physical treatment was more effective, leading to a higher cover of other species and proportion of natives. Here, the herbicide was not essential in the recovery of vegetation, although it was an important factor controlling blackberry. In places with less intense physical treatment, the herbicide application became important for the community recover. Control actions to recover the ecosystem should be constant in time using methods that take into account weed and native species features.

The story of 12 Chachapoyan mummies through multidetector computed tomography

Objective To assess the imaging findings in Chachapoyan mummies of Peru through multidetector computed tomography (MDCT). Materials and methods Twelve human mummies and three burial objects from Laguna de los Cóndores, Peru, about 500–1000 years old, were studied, using a MDCT unit. In addition to the standard whole-body acquisitions, high-resolution scans from areas of particular interest were acquired individually (e.g., temporal bone, teeth). Results Eight mummies were female, three male, and sex was indeterminable in one mummy; the age of the mummies included newborn, 0.7 years, 2.5 years, 13 years, 13 years, 16 years, and six between 20 and 40 years old. The stature of the mummies was reconstructed (mean ± standard deviation; adults: 145 ± 14 cm, adolescents: 116 ± 17 cm, 2.5 years old child: 72 cm, newborns: 41 ± 3 cm). Dental conditions were compromised in seven and excellent in five mummies. Besides a dislocation of the ossicles, temporal bones and ears were normal in all mummies. An occipital osteoma, a tuberculous spondylodiscitis, and also probable tuberculous erosions at one tarsal joint and one sacral bone, osteoarthritis or tuberculous affection of a sacroiliac joint, as well as five cases of pulmonary tuberculosis were observed. Ten mummies were buried in the fetal position, two were found packaged in bundles; the burial technique was studied in detail. A necklace was found with one mummy. The added burial objects were identified as skeletal parts of two leopardis pardalis and one lagothrix flavicauda. Conclusions MDCT non-invasively revealed information about age, sex, stature, diseases, burial practices and other cultural aspects of the Chachapoyas.

A new species of Branchinecta (Crustacea: Branchiopoda: Anostraca) from the Argentinian Tierra del Fuego

Branchinecta fueguina, a new species of fairy shrimp, was found together with B. granulosa in a temporary pond beside Laguna de los Cisnes, 53°47'12''S, 67°46'55''W, Tierra del Fuego, Antártida e Islas del Atlántico Sur Province (Argentina). The male second antennal basal article has a proximal, anteriomedial auriculate welt, covered with sensory setae and a hanging posteriomedial ornamented apophysis bending abruptly anteriorly with a rounded apex. Distally, the basal article has a longitudinal medial crest, proximally produced into a blunt posteriomedially directed point. The distal article is strongly rotated, articulating almost perpendicular to the basal article. The anterior surface of the article is triangular, from its proximal joint to the broadly explanate apex. Distally, the broadened article bends anteriorly forming a complex three-lobed apex. The peculiar joint with the basal article and the distal article shape are unique in the genus.

De Xarayes ao Pantanal: a cartografia de um mito geográfico

The subject of this article is the Laguna de los Xarayes, which represents a lasting geographical myth, like many others, as those of the lakes Eupana, Eldorado or Paytiti. It embodies a myth that appeared soon after 1600, and that was quickly incorporated in cartographical representations. On the maps it was drawn as a great lake or lagoon, in whose surroundings lived agriculture practicing Indians, lovely people who owned precious metals: they were the Xarayes. With such features it was already included in the early Dutch atlases, at the beginning of the 17th Century, becoming then a generally accepted component of the South American middle lands. Also the jesuitical cartography included it as the source of the river Paraguay. At the middle of the 18th Century, however, both by the commissioners in charge of the boundary settlement and the Jesuits recognized the Laguna de los Xarayes as the river Paraguay overflowing its banks during the rainy season. From then on this place was registered as the Pantanal.