Reconnaissance study of macrofossils from the upper purus river - Western Amazônia.

Fossils of wood, bone and teeth found along the Upper Purus River οf Amazonia. were studied using conventional microscopy and scanning electron microscopy. Mass spectometry was also used to investigate minor and trace element signatures of bone samples.The microsopy studies showed that there was little alteration of original textures. In the fossil wood samples, identified In thin section as tropical hardwood trees, the replacement of the original material with siderite suggests that fossilization occured in shallow sediments in which interstitial waters were saturated with respect to iron carbenate. In samples of both fossilized bone and wood, precipitation of secondary iron phases was commonly observed in cracks and voids. Other secondary phases Included silica, iron oxides, manganese carbonate. The intimate assοciation οf these secondary phases with the original biological structures could be evidence for a microbiological role in the formation of these phases. The similarity in rare earth element (REE) signatures for 2 fossil bone samples from different modern locations indicates their having shared similar diagenetic histories.The virtually complete preservation of original textures suggests that microscοpic studies could be useful in classifying fossil and even in identifying original materials. Rare carth signatures in fossilized bone may reflect ground water compositions at the time of fossilization.

Notes on the ethnoicthyology of fishermen from the Tocantins river (Brazil)

Ethnobiology includes the study of how populations perceive and classify organisms. This study focuses on the utilization and classification of fishes by fishermen from the Tocantins river. The study area is located between the cities of Imperatriz and Estreito (Maranhão and Tocantins States). Interviews with fishermen and collection of fish species were performed from October 1987 to June 1988. The criteria used by fishermen to classify fish species are mainly morphological, such as related to body shape and coloration. Fish habitat is also an information used in folk classification. Terrestrial plants and animals are a reference for some fish names. Fishermen showed a deeper knowledge and detailed classification of species of fish used for food, sale, or medicine. Folk classification represents the knowledge a population has on its environment, and it is more detailed on species which are part of its realized niche as indicated by this study.

THE VEGETATION OF A SEASONAL VÁRZEA FOREST IN THE LOWER SOLIMÕES RIVER, BRAZILIAN AMAZONIA

The species composition of the seasonal várzea forest growing on a bank of the Ilha de Marchantaria / lower Solimões-Amazonas River, Brazil was studied in an area of slightly less than one hectare. Two biomass plots were harvested. Forty-seven arboreal species representing 46 genera in 25 families were recorded. Tree density was 1086 per hectare. Total basal area was 45 m2 ha1. Mean species density was 6.5 ± 1.98 per 100 m2. The most abundant species were Crataeva benthamii(Capparidaceae), Laetia corymbutosa(Flacourtiaceae) and Vitex cymosa(Verbenaceae). The highest basal area per species was 10.2 m2 for Pseudobombax munguba(Bombacaceae). The common species are known to be typical floristic elements of the seasonal varzea forest. Above ground dry biomass was equal to 97 and 255 t ha', respectively. Its chemical composition is characterized by comparatively high bioelement contents equal to 2.4 percent on the average. Calcium was the most important bioelement. Structure of the forest and age darings of trees allow the successional classification of the stands.

Nutritional preferences of wood-feeding termites inhabiting floodplain forests of the Amazon River, Brazil

The alimentary preferences of five species of wood-feeding termites of the genus Nasutitermes that coexist in the inundated forests of the floodplains of the Amazon river várzea for species of fresh wood and for wood in different stages of decomposition was evaluated in laboratory tests. Wood of low density was generally preferred; the decay stages were preferred over fresh wood. The five termite species differ in the amplitude of their choices, indicating a strong differentiation in food choice among them. Differences in feeding preferences may be a niche-separating factor for these five Nasutitermes species of the floodplains.

Feeding of the Brycon cephalus, Triportheus elongatus and Semaprochilodus insignis (osteichthyes, characiformes) larvae in Solimões/Amazonas River and floodplain areas.

Information on larval fish feeding is essential for understanding their trophic relations, including the management in conditions totally or partially controlled by humans. An experiment was designed to evaluate the larval diets of three commercially important species. Four varzea-lakes and the adjacent river were sampled with bongo and hand nets from January 1993 to November 1995. Larval diets were evaluated by length-classes and capture sites, and were tested by two factor ANOVA. The larvae were feeding in all habitats, except in the flooded forests. The three species had different diets, which varied with their length and lake. The rotifers were the main initial food item of the three species, replaced by fish larvae in Brycon cephalus, cladocerans in Triportheus elongatus and detritus in Semaprochilodus insignis. The increase of the ingestion limit, as the larvae grew, was higher than the increase in the consumed prey size for the three species.

The systematic and biogeographical status of Fredius reflexifrons (Ortmann, 1897) and Fredius fittkaui (Bott, 1967) (Crustacea: Brachyura: Pseudothelphusidae) from the Amazon and Atlantic Guianas River basins

There is considerable confusion in the literature regarding the systematic position and distribution of two pseudothelphusid crabs originally described as Potamocarcinus reflexifrons Ortmann, 1897 and Potamocarcinus reflexifrons fittkaui Bott, 1967, and now included in the genus Fredius Pretzman, 1965, as F. reflexifrons and F. fittkaui. Study of numerous specimens from recent collections, together with a critical analysis of the data published in the literature, shows that both taxa could be easily separated by gonopodal characters. The two species occupy discrete areas of distribution along the main axis of the Amazon River and in the upper Rio Negro Basin, respectively, with an overlap in the Atlantic Guianas. It is postulated that they originated from a common ancestor, through a process of vicariance, in the two areas observed at present. Permeability of barriers allowed their further occupancy of the Atlantic Guianas after the marine regressions in this area.

Characterization of the commercial fish production landed at Manaus, Amazonas State, Brazil

The present work aims to update a series of information about the regional fishing production, by presenting and characterizing the contribution of the different sub-systems of the Amazon basin to the catch landed at the main fishing market of Manaus, Brazil, from 1994 to 1996. Collectors specifically hired for this function registered key information on the fisheries. Thirty nine types or groups of fish were found in the fishing production landed. Jaraqui (Semaprochilodus spp.), curimatã (Prochilodus nigricans), pacu (Myleinae), matrinchã (Brycon cephalus), sardine (Triportheus spp.), aracu (Anostomidae) and tambaqui (Colossoma macropomum) were the most important items during three consecutive years. In 1994 these items summed up 91.6% of the total production; in 1995 and 1996 these values were, respectively, 85.3% and 86.4% of the total production. Tambaqui landed decreased remarkably during the period 1976-1996. There was a strong seasonal component in the production of the main species; jaraqui and matrinchã were mostly landed between April and June, while curimatã, pacu, and sardine were mostly landed during the dry season. Other important items showed a strong inter-annual variation in their production. The fishing production landed came mostly from the sub-system of the Purus River (around 30% of the total production). The subsystem of the Medium-Solimões contributed with an average of 15% and the sub-systems of the Madeira, Lower-Solimões, Upper-Amazon and Juruá, together contributed with 11.5% of the total production landed. Finally, the remaining sub-systems contributed with only 7.6% of the production.

Presence of oOrganophosphate Insecticides in fish of the Amazon River

Trace levels of three organophosphate insecticides (OPI) were detected in eight fish species from the region of Santarém, State of Pará, Brazil. Individual concentrations of OPI in fish ranged from less than the detection limit to 2,1 ppb. Mean concentrations of chlorpyrifos, malathion, and methyl-parathion were 0,3 ± 0,3, 0,1 ± 0,1, and 0,3 ± 0,3 ppb, respectively. Pellona flavipinnis, the largest and fattest piscivorous species analyzed, was the most contaminated. Since an inhabitant of this Amazonian region consumes 220 g of fish per day on average, ingested doses of chlorpyrifos, malathion, and methyl-parathion may reach up to 308, 220, and 462 ng·d-1, respectively. Compared to acceptable daily intakes (ADI), quantities of OPI absorbed via fish consumption on a daily basis are far below deleterious levels. We estimated that even considering the highest OPI contents detected, the average daily fish consumption of anadult of 60 kg would have to increase by ca. 1 950, 5 450, and 2 600 times to reach ADI of chlorpyrifos, malathion, and methyl-parathion, respectively. Neither fish diet nor fish lipid content enabled us to completely explain the interspecific differences observed.

Seasonality, parity rates and transmission indices of Mansonella ozzardi (Manson) (Nematoda: Onchocercidae) by Cerqueirellum argentiscutum (Shelley & Luna Dias) (Diptera: Simulidae) in a lower Solimões River community, Amazonas, Brazil

Mansonella ozzardi is transmitted by two dipterian families, Ceratopogonidae (midges) and Simuliidae (black flies). In Brazil, black flies are vectors for this filariasis until now. In this paper, we determined the seasonality, parity capacity and parasitic infection rate of Cerqueirellum argentiscutum. The work was carried out in the Porto Japão community, Lower Solimões River, Amazonas, Brazil. Results show that the black flies were more abundant during the rainy season (from December to May). The number of parous flies was higher in every sampling during the course of year. Monthly Biting Rate (MBR1 123742.00, MBR2 86701.50) was high, although Parasitic Infection Rate (PIR1 0.06, PIR2 0.08) and Annual Transmission Potential (ATP 7.25) were low in numbers.

Geological characteristics of the nesting areas of the giant Amazon river turtle (Podocnemis expansa) in the Crixás-Açu river in Goiás State, Brazil

A large population of the giant Amazon river turtle (Podocnemis expansa) nests along the beaches of the Crixás-Açu River in the central western region of Brazil. In spite of the existence of several point bars in the area, only a selected group of beaches is used for nesting by P. expansa. Geological aspects, such as river width and depth, beach height above 200 cm with sandy sediments, were indispensable for the choice of these nesting sites. The relatively reduced dimensions of the point bars and the great number of turtles, which nest in the same local, contributed to the existence of a high nest concentration. The rapid rise of the Crixás-Açu River caused the flooding of the beaches and the drowning of hatchlings and embryos. It is estimated that nearly all the nests were lost. The height of the nesting place and the time of flooding related to the incubation period are decisive in embryo survivorship. The Retiro, Júnior, Assombrado and Limoeiro beaches, which are situated at heights of 183 to 310 cm, were inundated on 8 November 2000. The Barreira Branca beach, with a height of up to 380 cm was completely inundated on 13 December 2000. All of these beaches were flooded before the hatchlings emerged.

Treetop shelter of a neotropical river otter cub (Lontra longicaudis - Carnivora: Mustelidae) in an Amazonian flooded forest

The finding of a Neotropical river otter (Lontra longicaudis) cub occupying a shelter in a hollowed treetop is reported. The observation was made in a seasonally flooded forest in Central Amazonia, during the high water peak of the annual inundation cycle. A literature review indicates that this is the first description of a shelter of the species, both in a hollowed tree and in Amazonia. This observation can indicate a strong relationship between the species' breeding cycle with the annual dynamics of Amazonian rivers. We discuss potential advantages and disadvantages of breeding when water level is high.

A description of mercury in fishes from the Madeira River Basin, Amazon, Brazil

Over the last 20 years several projects carried on the Madeira River basin in the Amazon produced a great amount data on total Hg concentration in different fish species. In this paper we discuss temporal trends in Hg contamination and its relation to body weight in some of those fishes, showing that even within similar groups, such as carnivorous and non-migratory fish, the interspecies variability in Hg accumulation is considerable.

A synopsis of the species of Mesovelia (Insecta: Heteroptera: Mesoveliidae) occurring in the floodplain of the Amazon River, Brazil, with redescriptions of Mesovelia mulsanti White and M. zeteki Harris & Drake

Mesovelia mulsanti White, 1879 and M. zeteki Harris & Drake, 1941 are newly recorded in the Amazon River floodplain, Brazil. A key to the three known species ocurring in this region is also provided. Mesovelia mulsanti can be distinguished from M. amoena and M. zeteki by the body length larger than 2.50 mm, the head without longitudinal brown stripes near midline, and the forefemur and midfemur of the male, which have ventral rows of spines. Mesovelia amoena differs from M. zeteki in aspects of body color and in number of spinules near posterior margin of abdominal sternite VI of male.

A new species of Cerqueirellum Py-Daniel, 1983 (Diptera: Simuliidae) and proven new vector of mansonelliasis from the Ituxi River, Amazon basin, Brazil

A new species of the genus Cerqueirellum Py-Daniel, 1983 (Diptera: Simuliidae) is described. The adults are similar to the species C. oyapockense (Floch & Abonnenc, 1946) and C. roraimense (Nunes de Mello, 1974), of which the females are similar, and the males present discrete differences. The main differences of this new species to others of the genus Cerqueirellum are the integument of the larva recovered from stout spines and long cephalic trichomes in the pupa. Some females were infected with Mansonella ozzardii (Manson, 1897) (Nematoda, Onchocercidae) and probably transmit mansonelliasis in the Ituxi river, state of Amazonas, Brazil.

Caracterização físico-quimica de farinhas oriundas de variedades de mandioca utilizadas no vale do Juruá, Acre

Algumas características de farinha de mandioca dependem da variedade da raiz utilizada para o processamento. Objetivou-se avaliar as características físico-químicas da farinha de mandioca oriundas de variedades utilizadas no estado do Acre. Os tratamentos foram compostos pelas variedades: T1= Paxiubão, T2= Im221, T3 = Caboquinha, T4 = Araçá, T5 = Colonial, T6 = Branquinha, T7 = Panati e T8 = Mansa e Brava. Foram coletadas amostras das oito variedades de mandioca em casas-de-farinha no município de Cruzeiro do Sul, Acre. As raízes foram transportadas via aérea para o Laboratório de Tecnologia de Alimentos da Embrapa-AC, na cidade de Rio Branco, Acre. Foram avaliados: teor de umidade, cinzas, lipídios, proteína, fibra bruta, carboidratos, acidez, pH e atividade de água. Todas as amostras se apresentaram de acordo com os padrões estabelecidos pela Legislação Brasileira para farinha de mandioca quanto ao teor de umidade, cinzas e carboidratos. As farinhas analisadas apresentam teores baixos de fibras e baixa acidez. A atividade de água das farinhas analisadas esteve abaixo do limite mínimo capaz de permitir o desenvolvimento de microrganismos. As variedades Araçá, Colonial e Branquinha se mostraram adequadas para a fabricação de farinha de mandioca devido, principalmente, ao elevado teor de proteína e carboidratos presente nas farinhas produzidas.