North-central Brazil Research Articles

Circulation of Dengue Virus Serotype 1 Genotype V and Dengue Virus Serotype 2 Genotype III in Tocantins State, Northern Brazil, 2021-2022.

In Brazil, the state of Tocantins, located in north-central Brazil, has experienced a significant number of cases of arboviral disease, particularly Dengue virus (DENV). This study aimed to deepen the knowledge on DENV circulation within that state by conducting full genome sequencing of viral genomes recovered from 61 patients between June 2021 and July 2022. There were a total of 8807 and 20,692 cases in 2021 and 2022, respectively, as reported by the state's Secretary of Health. Nucleotide sequencing confirmed the circulation of DENV serotype 1, genotype V and DENV serotype 2, genotype III in the State. Younger age groups (4 to 43 years old) were mostly affected; however, no significant differences were detected regarding the gender distribution of cases in humans. Phylogenetic analysis revealed that the circulating viruses belong to DENV-1 genotype V American and DENV-2 genotype III Southeast Asian/American. The Bayesian analysis of DENV-1 genotype V genomes sequenced here are closely related to genomes previously sequenced in the state of São Paulo. Regarding the DENV-2 genotype III genomes, these clustered in a distinct, well-supported subclade, along with previously reported isolates from the states of Goiás and São Paulo. The findings reported here suggest that multiple introductions of these genotypes occurred in the Tocantins state. This observation highlights the importance of major population centers in Brazil on virus dispersion, such as those observed in other Latin American and North American countries. In the SNP analysis, DENV-1 displayed 122 distinct missense mutations, while DENV-2 had 44, with significant mutations predominantly occurring in the envelope and NS5 proteins. The analyses performed here highlight the concomitant circulation of distinct DENV-1 and -2 genotypes in some Brazilian states, underscoring the dynamic evolution of DENV and the relevance of surveillance efforts in supporting public health policies.

Predictability of extreme streamflow in Brazilian rivers through climate indices

In the present study empirical modeling was used to estimate extreme monthly streamflow in 161 locations of hydroelectric plants in the main Brazilians basins through a climate indices set. Principal components analysis was applied to capture the combined influences of climate indices variability. The main predictors of the models were climate patterns of tropical Atlantic and Pacific (Tropical Southern Atlantic and El Niño Southern Oscillation (ENSO) Modoki), complemented by high latitudes patterns (Antarctic Oscillation and Pacific North American Pattern). The contribution of the ENSO/Pacific Decadal Oscillation mode occurs in preferential months, especially in the transition seasons. There is also a contribution of the lagged streamflow itself, mainly in basins located in the Southeast of Brazil. The accuracy of the model for most of the Brazilian basins is higher than 70%, with higher values than 90% for the estimate of very low streamflow in northeast and north-central Brazil, as well as for very high streamflow in south-central region, which performance decreases with the increase in the lag. The results showed that the climate indices have a highly predictive potential for extreme streamflow, with a higher predictability for more long-term forecasts in case of very low streamflow than very high streamflow.

Rhyacian evolution of high-grade metamorphic rocks of the Porto Nacional Granulite Complex, based on geocronological data U-Pb-Hf in zircon and U- Pb in monazite

The Porto Nacional Complex in the northern portion of the Goiás Massif, in north-central Brazil, represents a Paleoproterozoic/Archean microcontinent reworked in the Neoproterozoic during the Brasiliano Cycle. This NE-SW-trending belt of high-grade metamorphic rocks consists, predominantly, of orthogranulites in addition to aluminous paragneisses that reached high-grade metamorphic conditions in the granulite facies (∼860 °C and 9 kbar). The zircon U–Pb geochronological results obtained on orthogranulite (enderbite) crystal cores yielded an age of 2.16 Ga, however, the crystal borders present lower values (2.09 Ga). These results represent, respectively, the age of igneous crystals of tonalitic protoliths, and high-grade metamorphism. The zircon crystals of another enderbite sample yielded lower values of about 2.09 Ga, reinforcing the interpretation of metamorphic zircons. The U–Pb geochronological results between 2.09 Ga and 2.10 Ga obtained on monazite from the aluminous paragneisses, coincide with the values obtained for enderbite metamorphic zircon crystals, allowing us to define the high-grade metamorphism age and the formation of igneous protoliths in the Rhyacian. This small age difference demonstrates the metamorphism role contemporary to the magmatism of the tonalitic protoliths of the Porto Nacional Complex, related to the Late-Transamazonian orogeny. The Hf-TDMC model ages suggest two crust formation episodes that gave rise to the following rocks: one from the Siderian (2.40–2.48 Ga) and another from the Neo-Mesoarchean (2.52–3.01 Ga). The positive petrogenetic parameters ƐHf(t) (+3.9 to +5.2) evidence a mantle source derivation for the Siderian material, while the negative and positive petrogenetic parameters ƐHf(t) (−4.6 to +3.3) indicate a mixture between crustal and juvenile material for the Neo-Mesoarchean material. These results allow us to disregard the proposed correlation between this high-grade metamorphic terrain with the Porangatu-Talismã Granulitic Belt, which occurs to the south of this region, whose thermo-tectonic evolution is related to the late Neoproterozoic. On the other hand, there are records of several other Rhyacian similar granulitic terrains, such as the granulites of the Bacajá and Tartarugal Grande in the Amazonian Craton, the Itabuna-Salvador-Curaçá Granulitic Belt in the São Francisco Craton, as well as in the Bakhuis Belt, in Suriname, and Limpopo Belt in the West African Craton.

Desenvolvimento regional do sudeste do Pará

Este artigo examinou o processo de desenvolvimento regional do sudeste do Pará, identificado como a parte do Estado pertencente à região de referência denominada Centro Norte do Brasil. A metodologia utilizada foi o Índice de Desenvolvimento Regional e, como recorte temporal, os anos de 2000 a 2010. Os principais resultados apontam para uma região onde o município de Marabá se destaca como lugar central, mas Parauapebas e Tucuruí também têm destaque, de formas e intensidades diferentes. De modo geral, todos os municípios avançaram no conjunto dos indicadores. A região tem aptidão para crescimento sustentado em uma economia de base exportadora, necessitando investir em agregação de valor ao produto regional, fixar os ganhos e internalizar seus benefícios. Do ponto de vista do capital social, ocorreram melhoras no período analisado, havendo, porém, espaço para o fortalecimento do empoderamento da sociedade organizada. Palavras-chave: Desenvolvimento Regional. Centro Norte. Sudeste do Pará. Índice de Desenvolvimento Regional.

Serra do Tapa Ophiolite Suite - Araguaia Belt: Geological characterization and Neoproterozoic evolution (central-northern Brazil)

The Araguaia Belt is a Neoproterozoic collisional orogen located in the northern Tocantins tectonic province, North-central Brazil, being one of the most expressive orogens of West Gondwana. The Serra do Tapa Ophiolite Suite is the most important representative of the ophiolitic bodies of the Araguaia Belt, exposed along the low-grade metamorphic domain of the Belt and extending over 80 km in the N-S direction. It constitutes a set of N-S aligned bodies that represent a disrupted ophiolite special sequence comprising serpentinized peridotites and dunites, massive and pillow basaltic lavas, volcanosedimentary rocks, cherts, jaspilites, and their metamorphic products. The serpentinized rocks have protoliths of mantelic harzburgites and dunites, with relict original protogranular texture partially replaced by pseudomorphic texture after olivine and orthopyroxene, and non-pseudomorphic (replacements). Submarine basaltic flows represent the volcanic succession, overlying serpentinized peridotites. The volcanic succession occurs as homogeneous massive basalts or pillow basalts, and locally volcanoclastic breccias (hyaloclastite). The pillow structure shows zoning, where the core consists of homogeneous massive metabasalt with preserved igneous features whereas pillow outer zone consists of hyalobasalt with quenching textures whose pillow surface is transformed into chlorite-rich rocks that appear fine-grained and related to the metasomatic transformations due to interactions with seawater. Geochemically, the massive metabasalts display a subalkaline-tholeiitic affinity, compatible with Middle Oceanic Ridge Basalts types (MORB). The suite evolution is a testimony of an oceanic stage during the Neoproterozoic of the Araguaia Basin that generated an oceanic lithosphere followed by volcanic activity, the interaction between lava flows and pelitic sediments, and deposition of chemical sedimentary rocks (jaspilites and cherts). Subsequently, the detachment of the oceanic lithosphere and the compressional tectonic evolution of the Araguaia Orogen inverted the sequence leading to the obduction of ophiolite bodies along overthrust and transcurrent faults projecting/thrusting a mass toward the Amazonian Craton. The tectonics was accompanied by regional metamorphism from anchymetamorphism to low greenschist facies conditions. All these processes are related to the evolution of the Brasiliano/Pan-African Cycle of the Araguaia Belt. The Serra do Tapa Ophiolite constitutes a mega-slice of an oceanic crust and marks a phase of lithosphere construction and the early opening of the Araguaia Basin related to the crustal evolution of the Araguaia Belt in the Neoproterozoic (transition Tonian-Ediacaran).

The Cambrian peraluminous Santa Luzia granite suite in the Araguaia Belt, central Brazil: Evidence for closure of the Clymene Ocean based on zircon and monazite U[sbnd]Pb data

The Araguaia Belt (AB) in northcentral Brazil formed as the result of the amalgamation of the Amazonian and São Francisco-Congo cratons along with the Parnaíba Block during late Neoproterozoic times. Ediacaran/Cambrian late- to post-orogenic magmatism took place at ∼540 Ma following this continental collision at 550-540 Ma. Such magmatism is represented in the southern portion of the Araguaia Belt by the peraluminous Santa Luzia and Barrolândia granites, as well as by the Presidente Kennedy Granodiorite in the central portion of the AB. Inherited zircon cores with distinct rims are abundant in the Santa Luzia Granite. This pluton yields UPb MC-LA-ICP-MS zircon and monazite ages of 538 ± 1 Ma and 534 ± 5 Ma, respectively. In addition, UPb zircon and monazite ages of 536 ± 6 Ma and 524 ± 6 Ma, respectively, are obtained for the Barrolândia Granite. The data presented in this work and in the literature allow to group the studied Santa Luzia and Barrolândia granites, together with Presidente Kennedy Granodiorite, in a single suite, named Santa Luzia Suite, maintaining the Santa Luzia pluton as the type-area. Rocks related to this Cambrian magmatism are essentially peraluminous, magnesian to slightly ferroan, and calc-alkaline in character. Such rocks probably originated from magmas formed by partial melting of meta-igneous sources that were subsequently contaminated via assimilation of metasedimentary rocks. In the AB, both the collision related to the 550-540 Ma Brasiliano/Pan-African orogeny, and the intimately associated ∼540 Ma late- to post-orogenic Santa Luzia Suite magmatism record the closure of the Clymene Ocean as well as the late stages of compressional tectonics related to west Gondwana amalgamation. The latter was followed by exhumation related to collapse of the Araguaia orogen.

Expansion of invasive Ceratium furcoides (Dinophyta) toward north-central Brazil: new records in tropical environments

Abstract: Aim We record new occurrences of the invasive species Ceratium furcoides in reservoirs and their affluents in the Paraná River basin, State of Goiás (GO), central-western Brazil, and in some localities in the São Francisco River basin, northeastern region. Methods Qualitative and quantitative phytoplankton samples were collected from Corumbá Reservoir and Cascatinha Falls, Caldas Novas, GO, and João Leite Reservoir, Goiânia, GO, both in the Paraná River basin, and samples from the São Franscisco River basin. Specimens of C. furcoides were observed with optical, epifluorescence and scanning electron microscopy. Results The individuals of C. furcoides from these environments agreed morphologically with populations in other reservoirs in Brazil and other locations, especially concerning the tabulation and the shape of the fourth apical plate. These environments ranged from oligotrophic to eutrophic conditions. Physical and chemical variables of these waterbodies, compared to other environments where this species was found, demonstrate that C. furcoides is a highly eurytopic species. The dispersal pattern of C. furcoides seems to be more complex than upstream-downstream regulation, since the species occurs in high-altitude environments and systems upstream from previously recorded locations. Conclusion An analysis based on the areas of occurrence and the chronology of the records demonstrated that C. furcoides has spread toward northern Brazil. Studies of the relationships among populations recorded in other parts of Brazil and South America are required in order to develop accurate models of dispersal for this invasive species, and will facilitate the development of management policies for aquatic systems in Brazil.

Buttonweed emergence as affected by seed burial depth and straw on the soil surface

Knowledge of the effects of seed burial depth and the presence of straw on the soil surface on weed seedling emergence provides useful information for the development of weed management tactics. Buttonweed (Borreria densiflora DC.) is a troublesome weed that occurs in large infestations in soybean and sugarcane crops from north-central Brazil. This study investigated buttonweed emergence at different seed burial depths and straw amounts present on the soil surface. The experiment was conducted in greenhouse conditions, under a factorial design between four seed burial depths and four amounts of surface straw. Percent seedling emergence and fresh biomass (g) were evaluated at twenty-five days after installation (DAI). Greater buttonweed emergence occurred in seeds that were placed on the soil surface either without surface straw or with up to 1,000 kg ha−1 of straw on the soil surface. With 4,000 kg ha−1 of surface straw, buttonweed emergence was prevented when seeds were placed at a depth of 0.5 cm or deeper in the soil. These data indicated emergence of this weed species was greater at depths near the soil surface and in soils with the least amounts of surface straw. Information generated in this study provides a starting point for the development of knowledge for understanding the biology of buttonweed emergence and its population dynamics. Such information may be directly transmitted to growers and lays the groundwork for an integrated management approach for this weed species.

Relationship between oxidative stability and antioxidant activity of oil extracted from the peel of Mauritia flexuosa fruits

Mauritia flexuosa is a species of palm belonging to the Arecaceae family that grows in extensive area along north-central Brazil, Colombia and Venezuela. The by-products of these fruits like the oil are of great economic and social importance in all countries where it grows; the oil extracted from fruits of M. flexuosa is used for cooking and is rich in monounsaturated fatty acids and natural antioxidants; and also, recently antiplatelet activity was reported. In order to better understand the thermal behavior and the antioxidant capacity of the oil extracted from the peel of M. flexuosa, the lipid profile, TG/DTG curve (under oxygen atmospheres), total phenolic content and the antioxidant activity were determined. The TG curve of the oil extracted from the peel of M. flexuosa showed a mass loss at a temperature ranging between 200 and 600 °C. The bigger decomposition step occurred in the temperature range of 200–420 °C, showing a similar thermal behavior than the canola and olive oils. Nevertheless, the studied oil showed a higher phenolic content at a degradation onset temperature (T0) than the other oils, and this is due to the structural characteristics of the polyphenols that have these oils. The antioxidant activity of the different oils by the DPPH radical scavenging method showed that there is a direct correlation between phenol contents and antioxidant activities of the oils. This study shows the importance of the M. flexuosa oil obtained from the peel as a potential source of natural antioxidants.

Palynofacies patterns of the Devonian of the Parnaíba Basin, Brazil: Paleoenvironmental implications

To help describe the paleoenvironmental interpretation of one the most extensive marine Devonian successions in Brazil, palynofacies analyses were conducted on 46 samples from the Itaim (Pragian–Givetian), Pimenteira (Givetian–Frasnian) and Cabeças (Famennian) formations of the Parnaíba Basin in north–central Brazil. For the palynofacies analyses, kerogen categories were counted and subjected to cluster analyses. Five palynofacies associations were identified for three studied sections: PseudoAOM palynofacies, which consists of amorphous organic matter (AOM), pseudoamorphous and coenobial algae Quadrisporites; Transl/Nbiostr. palynofacies, which consists of translucent non-biostructured phytoclasts (well-preserved and degraded), cuticles (well-preserved and degraded), Spongiophyton and Botryococcus; Marine microplankton palynofacies, which consists of acritarchs, prasinophytes and translucent biostructured phytoclasts; Opaque palynofacies, which consists of opaque phytoclasts (equidimensional and lath shaped); and Sporomorphs palynofacies, which consists of zoomorphs (e.g., Chitinozoa) and sporomorphs (e.g., spores). The stratigraphic distribution of the five palynofacies associations reflects a continuous terrestrial influx throughout marine succession. At the Pragian–Emsian age, the woody material of Transl/Nbioestr. palynofacies prevails, suggesting a marine depositional paleoenvironment (presence of marine palynomorphs), but under deltaic influence due to the input of terrigenous material. An increasing trend of marine elements of Marine microplankton palynofacies is recorded for the Givetian, which suggests a progressive marine influence. However, during the Frasnian, the highest abundance of marine elements was recorded (Marine microplankton palynofacies). Moreover, a bloom of Maranhites spp. and prasinophytes (e.g., Tasmanites and Cymatiosphaera) was also recorded. The abrupt increase of marine palynomorphs in the Frasnian – here termed the “Maranhites Event” – has been recorded by other authors. Finally, in the Famennian, woody material was most abundant in Transl/Nbiostr. palynofacies and Sporomorphs palynofacies, which reflects a depositional trend that is strongly controlled by fluvial input into a shallow marine environment.

Cantharellaceae of Guyana II: New species of Craterellus, new South American distribution records for Cantharellus guyanensis and Craterellus excelsus, and a key to the Neotropical taxa

Craterellus olivaceoluteus sp. nov. and Craterellus cinereofimbriatus sp. nov. are described as new to science. These fungi were collected from Guyana in association with ectomycorrhizal host trees in the genera Dicymbe (Fabaceae subfam. Caesalpinioideae) and Pakaraimaea (Dipterocarpaceae). Cantharellus guyanensis Mont., originally described from French Guiana, is redescribed from recent collections from Guyana, with additional range extensions for the species provided based on material examined from French Guiana, Venezuela, and north central, northeastern and southern Brazil, circumscribing nearly the entire Guiana Shield region and beyond. A new distribution record from French Guiana is provided for Craterellus excelsus T.W. Henkel & Aime. Macromorphological, micromorphological and habitat data are provided for the new species and C. guyanensis as well as DNA sequence data from the nuclear ribosomal regions of the internal transcribed spacer (ITS) and 28S large subunit (LSU); additional sequence data is provided for C. guyanensis and C. excelsus specimens collected outside Guyana. The relationships of these taxa within the Cantharellaceae were evaluated with phylogenetic analyses of ITS and LSU sequence data. This work brings the total number of Cantharellaceae species known from Guyana to eight. A key to the Cantharellus and Craterellus species known from the lowland Neotropics and extralimital montane Central and South America is provided.

Neoproterozoic granites of the Lajeado intrusive suite, north-center Brazil: A late Ediacaran remelting of a Paleoproterozoic crust

In north-central Brazil, a number of granite plutons, which intrude Paleoproterozoic gneiss-granulite terrains of the Goiás Massif, crop out along a thermal axis parallel to the Transbrasiliano Lineament. Single zircon lead evaporation ages from three granitic bodies span between 552 and 545 Ma. Sm–Nd model ages (TDM) vary between 2.1 and 1.7 Ga and negative εNd(0.55 Ga) values between −10 and −13 show that Paleoproterozoic crust was involved in the genesis of these granites. These plutons, which form the Lajeado Intrusive Suite are part of an important Ediacaran magmatic event in central-northern of the Tocantins Tectonic Province, composed of metaluminous to slightly peraluminous granites with geochemical characteristics similar to A-type granites, whose crystallization occurred under low water activity during magmatic emplacement. The granitic intrusive bodies are related to a crustal extensional/transtensional tectonic event at the end of the Neoproterozoic. They may have connection with the granitic plutons of similar age (0.56–0.52 Ga) in northwestern Ceará state, on the other side of the Paleozoic Parnaíba Basin in northwest of Borborema Province, along the Transbrasiliano Lineament.

Leopardus braccatus (Carnivora: Felidae)

Leopardus braccatus (Cope, 1889) is a small felid—not much larger than a domestic house cat—commonly called the Pantanal cat. No comprehensive surveys have been conducted to determine how many L. braccatus exist in the wild. It is found in humid, warm grasslands and wooded areas of extreme northwestern Argentina, southwestern and south- and north-central (newly reported ranges) Brazil, Paraguay, and Uruguay. Habitat loss and degradation are considered major threats throughout most of its range. It is uncommon in captivity and museum collections, listed with all Felidae under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, and considered “Near Threatened” by the International Union for Conservation of Nature and Natural Resources in the pampas cat group ( = L. colocolo).

Morphology, molecular phylogeny, and taxonomic inconsistencies in the study ofBradypussloths (Pilosa: Bradypodidae)

This study focuses on morphological and molecular data analyses, misidentifications, and phylogenetic inconsistencies regarding Bradypus variegatus (the brown-throated sloth) and B. tridactylus (the pale-throated sloth). Misidentifications were recorded on 75 of 313 museum specimens of Bradypus. Almost 90% of the misidentified specimens were B. variegatus from north-central Brazil, erroneously attributed to B. tridactylus. These misidentified specimens are reported in taxonomic reviews as the southernmost records of B. tridactylus. A history of confusing nomenclature regarding sloth species exists, and these particular misidentifications could be attributable to the similarity in face and throat color between B. variegatus from north-central Brazil and B. tridactylus. The molecular phylogeny of morphologically confirmed sloth specimens exhibits 2 monophyletic lineages representing B. variegatus and B. tridactylus. The split time between these 2 lineages was estimated at 6 million years ago (mya), contradicting previous studies that estimated this divergence to be 0.4 mya. Taxonomic inconsistencies were detected when comparing the molecular phylogeny to previously published DNA sequences ascribed to B. tridactylus. Misidentification or introgression could underlie such phylogenetic incongruities. Regardless of their causes, these discrepancies lead to misstatements regarding geographic distribution, phylogeny, and taxonomy of B. variegatus and B. tridactylus.

The Zorapteran Zorotypus huxleyi in Guyana (Zoraptera: Zorotypidae)

Insects of the order Zoraptera are infrequently collected and many entomologists are entirely unfamiliar with them. Species are typically encountered under bark, though often overlooked owing to their small size, somewhat cryptic coloration (relative to their subcortical habitats), and superficial resemblance to termites (Isoptera) or bark lice (Psocoptera). Accordingly, the available distribution information for zorapterans is scant and artificially gives the impression that species are highly endemic and poor dispersers. However, increasing sampling and information on the order indicates that some (if not many) species are relatively widespread and have better dispersal abilities than previously thought (Engel, 2001, 2007; Hinojosa-Diaz et al., 2006). As such, any new records for zorapteran distribution are noteworthy. Herein we document the occurrence of the species Zorotypus (Zorotypus) huxleyi Bolivar y Pieltain and Coronado (1963) in Guyana. The species was originally described from specimens collected in eastern Peru (near Pucallpa) and later recorded from elsewhere in northern and southern Peru (Engel, 2000, 2001). The species was subsequently captured near Manaus in north-central Brazil (New, 1978).

Integrated Middle and Late Devonian miospore and chitinozoan zonation of the Parnaíba Basin, Brazil: An update

New, hitherto unpublished miospore information from the Middle and Upper Devonian of the Parnaiba Basin, northeastern and northcentral Brazil, has enabled refinement of the chitinozoan zonation recently proposed for that basin. To a large extent, Devonian miospore zones defined for the Amazonas Basin can be also recognized in the Parnaiba Basin and other Western Gondwanan basins. The miospore zones are discussed and compared to the coeval Southern Euramerican miospore zonation, the regional Petrobras palynozones, and to the chitinozoan zonation of the Parnaiba Basin, additional Western Gondwanan regions, and other parts of the world.

The Discovery and Exploration of the Jacarè (“Alligator”) Nickel Laterite-Saprolite Deposit, Pará State, Brazil

The Jacare Nickel Laterite deposit lies in the western part of the Carajas region, north-central Brazil. Originally identified in the 1970?s and then abandoned, the property was acquired by Anglo American Brazil in 2000 and has passed through several progressive stages of exploration. An initial investigation indicated that nickeliferous laterites were present over the northern part of the 18kms long, 2.5kms wide ridge at Jacare, the result of deep tropical weathering of a bedrock mafic-ultramafic intrusive complex. Subsequent exploration has shown that the deposit contains three types of nickeliferous material comprising a siliceous laterite, a ferruginous laterite and a saprolite. Surface mapping, drill road mapping and sampling, pitting, drilling, and a reconnaissance TEM survey have all been employed to progress a geological evaluation and understanding of the deposit, outline the position and inter-relationships of the three main types of mineralization and identify additional resources. Nickeliferous saprolite in the northern and central parts of the deposit would be amenable to pyrometallurgical treatment, while the ferruginous laterites of the southern block could potentially feed a hydrometallurgical plant. The deposit at Jacare is seen as an important component of the Anglo American nickel portfolio in Brazil, which includes the existing mine at Codemin and the Barro Alto project. Exploration continues at the Jacare site, which is 100% controlled by Anglo American Brazil.

Taxonomic revision of the monotypic genus Acyphus Heller (Coleoptera: Curculionidae) with comments on infraspecific variation

Acyphus Heller, 1921 is a monotypic genus of Entiminae, Naupactini, ranging in north-central Argentina, southern Brazil, Paraguay and Uruguay. Its single species is mainly associated to trees of the genus Prosopis (Leguminosae), with several species ranging throughout the xerophytic forests of the Chacoan subregion. The genus is easily recognized by the presence of 20 elytral striae and the robust antennae, with strongly dilated scape, compressed from near base onwards. Acyphus renggeri (Labram & Imhoff) -senior synonym of Acyphus funicularis Hellershows variation in the distribution and density of the scaly vestiture of the elytra. There is a morphotype devoid of distinct scales and two squamose morphotypes with different irregular nebulose pattern. The paper includes descriptions of the genus and its only species, habitus photographs, line drawings of genitalia and mouth parts, and a map of distribution.

A new species of Remijia (Rubiaceae) from Amazonian Brazil

Remijia hubbardiorum B. M. Boom, endemic to white sandcampinas orerra firme forest in the Rio Uatuma region in the State of Amazonas of north central Brazil, is described and illustrated, and its morphological differentiation with respect toR. asperula Standley is discussed.

A Review of the Genera Roentgenia and Potamoganos (Bignoniaceae)

Roentgenia and Potamoganos (Bignoniaceae) are small genera of lianas with corollas that are closely related to larger and more well known genera such as Cydista, Clytostoma, and perhaps Phryganocydia. Roentgenia is ditypic, containing R. bracteomana and R. sordida, whereas Potamoganos is monotypic, containing only P. microcalyx. The two species of Roentgenia have white to lavender, campanulate-funnelform, Cydista-type corollas, stems with eight phloem arms, bi-trifid tendrils, 3(-4)-colpate pollen with reticulate exine, 2-seriate ovule organization, nectariferous disk lacking, linear-oblong fruit, and winged seeds. Roentgenia bracteomana is distributed from southern Colombia to northern Bolivia and north-central Brazil, whereas R. sordida is restricted to eastern Venezuela, Guyana, Suriname, French Guyana, and portions of northern Brazil. Potamoganos microcalyx has lavender to magenta, campanulate-funnelform, Cydista-type corollas, with four phloem arms, trifid tendrils, 3-colpate pollen with reticulate exine, 4-seriate ovule organization, and a nectariferous disk. Potamoganos microcalyx is known from southern Venezuela, Guyana, Suriname, and northernmost Brazil. A key to species, maps of species distributions, reproductive phenology, and illustrations of R. bracteomana and P. microcalyx are provided.