Northwestern Uruguay Research Articles

Mobility and raw material procurement by Fishtail people in Uruguay: Evaluation of silcrete long distance transport between campsites and outcrops during the late Pleistocene (ca. 12,900–12,250 cal BP)

Lithic artifacts from late Pleistocene manufactured in silcrete are used to understand Fishtail behaviors linked to mobility, land use and raw material acquisition during early prehistory in Uruguay. The data analyzed here include three categories of silcrete evidence: (1) a database of Fishtail points, (2) regional outcrops of these lithic resource, (3) debitage and unifacial tools from campsites. We calculated the cumulative cost of movement between campsites and the nearest lithic resources in space, located within the silcrete area, the distances involved in such movements, and the possible connection routes between campsites and silcrete resources. We analyzed the raw materials, density and spatial distribution of Fishtail points, and generated a Predictive Model of Transit Pathways. The results obtained indicate that silcretes were transported over long distances in mobility networks by an extensive Paleoamerican social landscape from outcrops located in the western and southwestern to campsites in northwestern Uruguay at distances ranging between ∼ 179 and 482 km. This new data confirms long distance displacements, the high social value, and the preference of this lithic resource for the production of tool assemblages by the Fishtail peoples of Uruguay.

Listeria innocua e serotipos do Listeria monocytogenes isoladas dos casos clínicos em pequenos ruminantes no noroeste do Uruguai

ABSTRACT: Listeriosis is an infectious disease caused by bacteria of the genus Listeria, the neurological form being more common in ruminants. There are many reports of listeriosis in small ruminants in the region that includes Brazil, Argentina and Uruguay. However, these diagnoses were mainly based on histological lesions in the central nervous system (CNS) without the isolation and characterization of the involved Listeria strains. The aim of this study was to report sheep and goats listeriosis cases from 2016 to 2021 in northwestern Uruguay. The diagnosis was made according to lesions observed at histopathology, plus Listeria isolation in CNS, identifying it at specie and serotype level. Nine animals (n=9) of three outbreaks and five sporadic cases of listeriosis were studied. Sheep was the species with more cases in relation to goats, and adults were the category most affected. Cases occurred in spring and less frequently in winter. All presented neurological clinical signs and the lesions in the CNS were consistent with suppurative meningoencephalitis and micro-abscesses in the brainstem. In eight of nine CNS samples, Listeria strains were isolated (seven L. monocytogenes and one L. innocua). All the L. monocytogenes isolates carried the inlA gene; serotyping showed that four strains belonged to serotype 1/2b, two isolates belonged to serotype 4b, and one to serotype 1/2a. Considering that listeriosis is a common disease in this region and the fact that isolates are scarcely recovered from small ruminants, it would be important to emphasize the need for Listeria isolation to better characterize the strains that affect animals. Not only to improve knowledge about the epidemiology of disease but also with the objective of developing serotype specific vaccines for animal use.

<i>Corrigendum to</i>: Understanding <i>Praxelis</i> (Asteraceae, Eupatorieae): an updated taxonomy with lectotypifications and morphological and distributional clarifications

The South American genus <i>Praxelis</i> Cass. (Asteraceae, Eupatorieae) includes 18 species and is the second-largest genus of subtribe Praxelinae. It is distributed from Colombia, Venezuela and the Guianas, to central Argentina, southern Brazil and north-western Uruguay. Over the past 40years, one species, <i>P. clematidea</i>, has invaded several countries around the world. To understand <i>Praxelis</i> and its species, this study provides an updated taxonomy with the re-establishment of <i>P. urticeafolim</i> var. <i>nanum</i> as a synonym of <i>P. ostenii</i>, 16 lectotypifications, clarification of morphology and geographical distribution, brief descriptions, and the first key to all the species in the genus.

New data for palaeoclimatic reconstructions in the upper/middle Uruguay River Basin: caesalpinioid Fabaceae woods in the Late Pleistocene

AbstractThe El Palmar Formation is the principal unit deposited during the Late Pleistocene by the Uruguay River in eastern Entre Ríos province, Argentina and north-western Uruguay. The Arroyo Yuquerí fossiliferous locality (c. 31°36′ S, 58°06′ W), part of the El Palmar Formation, is one of the richest sites in fossil woods. This article describes and determines 11 fossil woods, including seven new species closely related to modern Parapiptadenia, Microlobius, Anadenanthera, Pseudopiptadenia (Mimoseae, Fabaceae) and Chloroleucon, Enterolobium and Cedrelinga (Ingeae, Fabaceae). Coexistence approach, nearest living relatives (NLR) methods and mesomorphic and vulnerability indices were used to determine palaeoclimatic conditions. Comparisons of NLR of fossil woods, coupled with other previously identified taxa, suggest that a mature and evergreen woodland was present in the middle Uruguay River Basin during some Pleistocene events (MIS 5a and MIS7, according to absolute datings of the fossiliferous sedimentary unit). This caesalpinoid legume woodland was shaped by an environment with abundant humidity, and the structure of the water conduction system in the studied species was efficient. Finally, the results indicate a more humid and warmer climate than at present in the study area.

Nutrient levels, trophic status and land-use influences on streams, rivers and lakes in a protected floodplain of Uruguay

Land-use intensification impacts freshwater ecosystems in many agricultural landscapes, including the Rio de la Plata grasslands in Southeastern South America. We evaluated water chemistry of rivers, streams and lakes associated with a protected river-floodplain in the Queguay River basin in Uruguay. From 2019–2021, we measured phosphorus (P) and nitrogen (N) forms, dissolved oxygen (DO), turbidity and other chemical parameters; basin-scale land-use via Sentinel satellite imagery; and trophic status based on nutrient concentrations and Principal Components Analysis (PCA). Results highlighted low nutrient concentrations in the Queguay rivers, indicating this watershed as a national reference for evaluating eutrophication in Uruguay. Levels of total nitrogen (TN) in rivers averaged 430–510 µg/L and total phosphorus (TP) averaged 44–51 µg/L, classifying them as oligotrophic-mesotrophic systems. Streams ranged in TP from 51 to 97 µg/L and in TN from 545 to 701 µg/L, suggesting meso- to eutrophic states according to TP levels, and potential anthropogenic eutrophication in smaller basins with crop cover > 25%. Floodplain lakes are a conservation target within the protected area and had TP averaging 74–109 µg/L, suggesting eutrophic-hypereutrophic states based on TP and potential external nutrient inputs. The positive correlation between basin-scale crop cover and mean TP and soluble reactive phosphorus (SRP) concentrations suggested that land-cover plays a role in nutrient levels of fluvial and lotic systems. This study establishes a baseline for water chemistry in lakes and fluvial ecosystems in the Queguay River basin within an extensive agricultural region of the La Plata River Grasslands. By providing the first time series dataset of water chemistry for this area, we fill a major geographical gap regarding the limnological attributes of freshwater ecosystems in northwestern Uruguay. Results highlight the value of the Queguay basin for freshwater habitat conservation, and the vulnerability of these systems to land cover changes and nutrient loading from external sources.

Petrological features of the first Cenozoic alkaline magmatic event recorded in northwestern Uruguay, southern extreme of the Paraná basin

The Cenozoic mafic alkaline rocks found in northwestern Uruguay, in the southernmost portion of the Paraná Basin, comprise three subvolcanic plugs composed of Ne-tephrites. They cut through basalts that make up the Paraná Magmatic Province as well as part of the sandstones of the Late Jurassic–Early Cretaceous age. These mafic rocks are characterized by an aphanitic hypocrystalline texture that is occasionally porphyritic with pyroxene and olivine macrocrysts/xenocrysts. We present the first lithogeochemical results that also include the Sr–Nd–Pb isotopes to determine the petrogenetic processes. These mafic rocks are enriched in light rare earth elements (La/LuN = 23.12–28.81) with respect to chondrite, in large-ion lithophile elements (Ba, U, and La), and in high-field-strength elements, such as Ta, Nb, and Zr, with respect to primitive mantle, and have a Mg# of 0.53–0.56. The trace element geochemistry and isotopic data (low radiogenic 206Pb/204Pb and low 87Sr/86Sri between 18.315 and 18.733, 0.70397 and 0.70443, respectively) indicate that the primary magma could be the product of the melting of an enriched mantle source with the possible involvement of metasomatic processes, lacking significant contamination by the continental crust. The K–Ar (whole rock) geochronology conducted on two samples yielded ages of 63.7 ± 2.5 and 51.5 ± 1.7 Ma for this magmatic event.

Understanding

The South American genus Praxelis Cass. (Asteraceae, Eupatorieae) includes 18 species and is the second-largest genus of subtribe Praxelinae. It is distributed from Colombia, Venezuela and the Guianas, to central Argentina, southern Brazil and north-western Uruguay. Over the past 40 years, one species, P. clematidea, has invaded several countries around the world. To understand Praxelis and its species, this study provides an updated taxonomy with the re-establishment of P. urticeafolim var. nanum as a synonym of P. ostenii, 16 lectotypifications, clarification of morphology and geographical distribution, brief descriptions, and the first key to all the species in the genus.

Praxelis clematidea (Asteraceae, Eupatorieae, Praxelinae) in Uruguay: first record of the genus and the species

During the revision of the southern South American species of Praxelis, populations of P. clematidea were found in northwestern Uruguay. In this study, we provide the first record of the genus and the species for the Uruguayan flora, along with taxonomic and morphological analyses based on herbarium specimens and field observations. In addition, uses of P. clematidea, its distribution and habitat, common names, an illustration and a key to differentiate the species of Praxelis of Uruguay and surrounding areas of Argentina and Brazil are presented.

Impact of nitrogen and phosphorous on biomass yield, nitrogen efficiency, and nutrient removal of perennial grasses for bioenergy

Perennial grasses are the promising source of bioenergy in South America which could provide several environmental benefits such as reduction in the greenhouse gasses emissions and reduction of nutrients and soil losses. Our objective was to determine the impact of N and P fertilization on biomass yield, N use efficiency (NUE), apparent N recovery (ANR), and nutrient removal (NR) on three perennial grasses: elephantgrass (Pennisetum purpureum Schum.), giant reed (Arundo donax L.), and switchgrass (Panicum virgatum L.). Four fertility treatments were evaluated in a 8-year field study in northwestern Uruguay: 1. control (No fertilizer), 2.100 kg N ha−1 year−1, 3.100 kg P2O5 ha−1 year−1, and 4.100 kg N + 100 kg P2O5 ha−1 year−1. Across years, elephantgrass had the highest biomass yield followed by giant reed and switchgrass (18.9, 16.3, and 14.1 Mg ha−1, respectively). Biomass yield increased 46% when N fertilizer was added, compared to the control. A low response was detected for P fertilization on all grasses, probably for initial P soil content (≥9 g kg−1). Elephantgrass had the highest NUE (70 kg kg−1 N), however, it had the highest total NR on these eight years (899, 226, and 2800 kg ha−1 for N–P–K, respectively) among the grasses, indicating a potential for increased fertilization input over time. Switchgrass had the lowest average ANR (19%) and NR (334, 45, and 166 kg ha−1, respectively). Therefore, even though switchgrass presented the lowest biomass yield, it is an excellent option as low-input bioenergies grass for temperate regions.

Tipos de resistencia de la ganadería familiar en el noroeste uruguayo

A pesar del avance del capitalismo agrario sobre los pastizales pampeanos, aún la mayoría de los agricultores familiares de Uruguay son productores ganaderos, dedicados a la cria mixta de bovinos y ovinos. En el marco de una investigación mayor sobre prácticas de resistencia de la agricultura familiar, se utilizaron conceptos de la obra de Bourdieu, tales como el sentido práctico y el habitus campesino, para analizar las estrategias de resistencia de los agricultores familiares en el noroeste de Uruguay. Un estudio de tipo etnográfico de dieciséis familias ganaderas, a traves del “Enfoque Global de las Explotaciones Agrícolas” y relatos de vida de las familias, permitió identificar las estrategias (económicas, educativas, sucesorias y simbólicas), y tipificar las resistencias de estos ganaderos familiares. Se discute el papel de las condiciones endógenas y exógenas en los objetivos de las familias y en las prácticas y estrategias generadas.

Novedades del género Tillandsia (Bromeliaceae, Tillandsioideae) para Uruguay

Se citan por primera vez para la flora de Uruguay a Tillandsia capillaris Ruiz & Pav. (= T. capillaris f. hieronymi (Mez) L.B. Sm.) y T. loliacea Mart. ex Schult. f. Tillandsia capillaris es registrada como una especie introducida y espontánea para la ciudad de Montevideo, mientras que T. loliacea es citada como especie nativa del noroeste del país. Se presenta el primer registro de T. tricholepis Baker para ambientes naturales de Uruguay, confirmando el estatus de especie nativa. Se reporta el hallazgo reciente de T. xiphioides Ker Gawl. luego de 73 años sin ser colectada en Uruguay. Este trabajo provee una descripción morfológica para cada especie, incluyendo información sobre su hábitat, distribución geográfica, fenología, estatus de conservación e imágenes.

Silcrete procurement system in Uruguayan prehistory

This paper summarizes information on the role of silcrete rocks as raw material in Uruguayan Prehistory. The spatial distribution of sources, the procurement strategies and projectile point technology are discussed. We present a lithic database for Northern, Central and Southern Uruguay, especially from the Los Indios archaeological site (Department of Rocha) in the Eastern lowlands, to illustrate the use of silcrete in lithic bifacial technology, particularly in the production of projectile points.In this paper, thin-sections of archaeological materials from the early and middle levels (between ca 3.5ky and ca 7.0kyBP) from Los Indios site were also examined, as well as geological samples from potential quarries in the Departments of Soriano and Flores. Finally, the paper discusses the different strategies used to obtain and transport lithic raw materials from distant quarries in Central and Northwestern Uruguay to the Atlantic coast.

Anaplasma platys in dogs from Uruguay

Anaplasmataceae family members include vector-borne bacteria of veterinary importance that may also affect humans. Ehrlichia canis and Anaplasma platys are the main members of this family detected in dogs worldwide. In Uruguay there are not many published studies on tick-borne pathogens affecting dogs, the only haemoparasite molecularly confirmed in dogs, is the piroplasm Rangelia vitalii. The aim of the present work was to detect the presence of A. platys and E. canis in dogs and dogs-associated ticks of two localities in Northwestern Uruguay. Blood samples from dogs with and without clinical signs associated with vector-borne diseases, and Rhipicephalus sanguineus obtained from these dogs were analyzed by PCR for Anaplasmataceae. Positive dogs were further analyzed by PCR for Ehrlichia spp. and A. platys. All the ticks were found negative. No dog was detected infected with E. canis, while eight dogs (4.2%) were found to be infected with A. platys. Phylogenetic analysis of groESL operon sequence for A. platys revealed no differences with sequences described for A. platys in neighbor countries and from other regions of the world. This is the first report of the presence of A. platys in Uruguay.

Food habits of the Broad‐snouted Caiman (Caiman latirostris: Crocodylia, Alligatoridae) in northwestern Uruguay

The food habits of the Broad‐snouted Caiman (Caiman latirostris) were studied in northwestern Uruguay. The most common prey were insects, the shrimp Pseudopalaemon bouvieri, the snail Pomacea canaliculata, fish and birds. Spiders, crabs, amphibians, snakes, turtles and mammals were consumed less frequently. Arthropods were the most frequent prey for juvenile caiman. Fish and snails were consumed by all size classes. The proportion of stomach contents with invertebrates decreased with increasing caiman size, and that with vertebrates was greater in the diet of larger caiman. Diet composition and ontogenetic shift are similar to that of other crocodilians considered as opportunistic generalist predators. Se estudiaron los hábitos alimenticios del Yacaré (Caiman latirostris) en el noroeste de Uruguay. Las presas más comunes fueron insectos, el camarón Pseudopalaemon bouvieri, el caracol Pomacea canaliculata, peces y aves. Arañas, cangrejos, anfibios, serpientes, tortugas y mamíferos fueron consumidos menos frecuentemente. Los artrópodos fueron las presas más frecuentes de juveniles. Peces y aves fueron consumidos por todos los tamaños. La proporción de contenidos estomacales con invertebrados disminuyó al aumentar el tamaño de los caimanes, y la de vertebrados fue mayor en los individuos de mayor tamaño. La composición y cambio ontogenético en la dieta resultan similares a los de crocodilianos considerados predadores generalistas oportunistas.

Conservation Status of Caiman latirostris (Crocodylia: Alligatoridae) in Disturbed Landscapes of Northwestern Uruguay

Demographic studies on crocodilians in subject to strong human disturbance habitats are scarce, particularly in the Neotropical Region. This work provides the first survey data of abundance and population size structure of a neotropical caiman, Caiman latirostris, in disturbed habitats of northwestern Uruguay (30°S, 57°W). We conducted nocturnal surveys in agriculture impoundments (2–116 ha) of the Ñaquiñá and Lenguazo stream basins during summer, from 2001 to 2004. About 81% of impoundments were inhabited by caiman, with relative abundance indices between 2.1 and 4.4 × km−1. Population size structure in the study area was similar throughout the study period; sub-adults from 50 to 119 cm of total length were the most abundant (57–78%), followed by adults (25–33%), and juveniles (6–22%). Relative abundance indices suggested that C. latirostris is not seriously endangered in contrast to previous local reports. The construction of agriculture impoundments in northwestern Uruguay for irrigation of rice and sugar cane seem to have been favored C. latirostris, as indicated by population size structure.

Geographic distribution and conservation status of Caiman latirostris (Crocodylia, Alligatoridae) in Uruguay

Geographic distribution and conservation status of Caiman latirostris (Crocodylia, Alligatoridae) in Uruguay. Populations of Caiman latirostris are known to occur in Uruguay but their geographic distribution remains uncertain. This work presents an update of the species distribution and conservation status in Uruguay. Surveys conducted by the authors confirmed the presence of this species in the previously known distribution range of northwestern Uruguay, where it seems to be widespread and relatively abundant in contrast to earlier reports. We report new localities for C. latirostris, most relevant being those of the Cebollati and Tacuari Rivers, and the Pelotas, India Muerta and San Miguel stream basins, which significantly expand its distribution through important wetlands in the eastern part of the country. The overall distribution is coincident with different landscape types, where lagoons, artificial impoundments, livestock waterholes, rivers, streams, creeks and marshes are inhabited by caiman. Illegal non-commercial hunting was detected all over the country.

A new species, Herbertia crosae (Iridaceae), from Uruguay

Abstract Roitman, G. G. (Catedra de Jardineria. Facultad de Agronomia, Universidad de Buenos Aires, Av. San Martin 4453. 1417. Buenos Aires, Argentina; roitman@mail.agro.uba.ar) & A. Castillo (Jardin Botanico de Ezeiza, Jujuy 1037, 1804, Ezeiza, Prov. de Buenos Aires, Argentina; ezeizabotgard@hotmail.com). A new species, Herbertia crosae (Iridaceae), from Uruguay. Brittonia 56: 361–364. 2004.—Herbertia crosae (Iridaceae) is described from the stony grasslands of northwestern Uruguay. The new species resembles Herbertia lahue but can be easily distinguished by the narrower leaves, slender habit, the smaller pale lilac flowers, the presence of yellow spots at the base of the tepals, the red, adpressed hairs along the filament column, the presence of filaments free at the apex, the channeled style arm, the recurved secondary divisions of the style arm, and the smaller fruits. A key to the species of the genus is provided in which five species are now recognized.

A Revision of the Forcipomyia squamitibia Group in the Neotropics with the Description of Three New Species (Diptera: Ceratopogonidae)

—A revision of the Neotropical species of the Forcipomyia squamitibia group, revealed three new species, F. (F.) catarinensis from southern Brazil, Colombia and Costa Rica, F. (F.) quechua from northwestern Argentina and F. (F.) rioplatensis from northeastern Argentina and northwestern Uruguay, which are described and illustrated. Forcipomyia (F.) squamitibia Lutz is redescribed from the original type material, a lectotype is designated, and F. (F.) soriai Wirth is recognised as a junior synonym. The remaining known species of this group are diagnosed, and keys to males and females are provided for the identification of the nine recognised species.

Morphological, Physical and Chemical Properties of Major Soils from Calagua in Northwestern Uruguay

AbstractVertisols, Alfisols, and Mollisols were identified in a soil survey of the area of Calagua in northwestern Uruguay. They are generally deep, dark‐colored, with well‐developed structure, high in CEC and base saturation, and can hold and supply sufficient amounts of water and nutrients for crops. Most are developed from clay sediments derived from basalt or quaternary mudstones. Most pH values of the surface layers are around 6.0 indicating no apparent danger from either exchangeable aluminum or excess of carbonates. Potassium and phosphorus levels are strikingly low. The soils of Calagua appear to have a great potential for field crops such as rice, sugarcane, and sorghum as well as for horticultural crops such as tomatoes, melons and cabbage. Any program geared to improve crop production in the area must provide for efficient irrigation techniques at critical growth periods, drainage, and the rational use of nitrogen, phosphorus and potassium fertilizers.

Morphological, Physical and Chemical Properties of Major Soils from Calagua in Northwestern Uruguay

Morphological, Physical and Chemical Properties of Major Soils from Calagua in Northwestern Uruguay