Ecological distribution of the shrimp Litopenaeus schmitti (Burkenroad, 1936) (Decapoda, Penaeoidea) in Ubatuba Bay, Sao Paulo, Brazil

The penaeidean Litopenaeus schmitti, popularly known as white shrimp, is a species of great economic importance, being a target of fishing fleets in the southeast region of Brazil. It is distributed through the western Atlantic, from Cuba to Brazil, until Rio Grande do Sul. Adults are found from shallow depths up to 30 m and have been found to depths of 47 m in the state of Rio de Janeiro, while juveniles are located in bays and estuaries. The studied species is seasonally distributed in the region of Ubatuba. The objectives of this study are to analyze the abundance and ecological distribution of L. schmitti and to assess if and when juveniles use the Indaia estuary during their life cycle. Furthermore, the hypothesis was tested that the main period of recruitment in the bay coincides with the period of closure of fisheries defined by the Instruction of IBAMA. To that end, samples were taken monthly from July 2005 through June 2007, both in Ubatuba Bay and in the estuary formed by the Rio Indaia. At each sampling station, salinity, temperature (bottom), depth, organic matter content (%), and grain size of sediments were measured. We found that the largest catches in the estuary were in late spring and early summer. In Ubatuba Bay, peak catches occurred during winter and early spring, whereas in the second year, already in May, there was a high peak capture. The variation in the number of individuals was correlated with some environmental factors both in the estuary and in the inlet (p < 0.05). In the estuary, abundance was positively correlated with temperature (p = 0.008) and organic matter (p = 0.025) and negatively with depth (p = 0.009). Regarding the Ubatuba Bay, only temperature (p = 0.034) and depth (p = 0.013) were significantly associated with the distribution of the shrimp, both being negative relations. The shrimp L. schmitti uses both the estuarine as well the shore environment, particularly the Ubatuba estuary and its adjacent bay, to complete its life cycle. The proposed period of fisheries closure (between March to May in the state of Sao Paulo) for this and other shrimps coincides with individuals capable of reproduction entering the inlet and thus are being protected.

Taxonomic revision of doubtful Brazilian freshwater shrimp species of genus Macrobrachium (Decapoda, Palaemonidae)

The freshwater prawns of the genus Macrobrachium Spence Bate, 1868 are widely distributed in rivers of tropical and subtropical regions and represent an interesting group with controversial taxonomy. The morphological characters traditionally used to separate species have shown a high intraspecific variation. Doubts about the status of M. birai Lobao, Melo & Fernandes, 1986, M. holthuisi Genofre & Lobao, 1978 and M. petronioi Melo, Lobao & Fernandes, 1986 have been arisen due to the high resemblance of the former two species with M. olfersi (Wiegmann, 1836), and the latter one with M. potiuna (Muller, 1880). Therefore, we performed a detailed morphological analysis of these species, including new characters not usually used in the species recognition. The present results here with molecular data lead us to conclude that M. birai and M. holthuisi are junior synonyms of M. olfersi, and M. petronioi is a junior synonym of M. potiuna. Considering these synonymies, 17 valid species are now reported for the Brazilian territory.

Kinetic Analysis of Gill (Na+,K+)-ATPase Activity in Selected Ontogenetic Stages of the Amazon River Shrimp, (Decapoda, Palaemonidae): Interactions at ATP- and Cation-Binding Sites

We investigated modulation by ATP, Mg2+, Na+, K+ and NH4 (+) and inhibition by ouabain of (Na+,K+)-ATPase activity in microsomal homogenates of whole zoeae I and decapodid III (formerly zoea IX) and whole-body and gill homogenates of juvenile and adult Amazon River shrimps, . (Na+,K+)-ATPase-specific activity was increased twofold in decapodid III compared to zoea I, juveniles and adults, suggesting an important role in this ontogenetic stage. The apparent affinity for ATP ( (M) = 0.09 +/- A 0.01 mmol L-1) of the decapodid III (Na+,K+)-ATPase, about twofold greater than the other stages, further highlights this relevance. Modulation of (Na+,K+)-ATPase activity by K+ also revealed a threefold greater affinity for K+ ( (0.5) = 0.91 +/- A 0.04 mmol L-1) in decapodid III than in other stages; NH4 (+) had no modulatory effect. The affinity for Na+ ( (0.5) = 13.2 +/- A 0.6 mmol L-1) of zoea I (Na+,K+)-ATPase was fourfold less than other stages. Modulation by Na+, Mg2+ and NH4 (+) obeyed cooperative kinetics, while K+ modulation exhibited Michaelis-Menten behavior. Rates of maximal Mg2+ stimulation of ouabain-insensitive ATPase activity differed in each ontogenetic stage, suggesting that Mg2+-stimulated ATPases other than (Na+,K+)-ATPase are present. Ouabain inhibition suggests that, among the various ATPase activities present in the different stages, Na+-ATPase may be involved in the ontogeny of osmoregulation in larval The NH4 (+)-stimulated, ouabain-insensitive ATPase activity seen in zoea I and decapodid III may reflect a stage-specific means of ammonia excretion since functional gills are absent in the early larval stages.

Geochemistry and Pb-207/Pb-206 zircon ages of granitoids from the southern portion of the Tamboril-Santa Quiteria granitic-migmatitic complex, Ceara Central Domain, Borborema Province (NE Brazil)

The Tamboril-Santa Quiteria Complex is an important Neoproterozoic granitic-migmatitic unit from the Ceara Central Domain that developed from ca. 650 to 610 Ma. In general the granitoids range in composition from diorite to granite with predominance (up to 85%) of granitic to monzogranitic composition with biotite as the main mafic AFM phase. Geochemical and Pb-207/Pb-206 evaporation zircon geochronology studies were applied in a group of these abundant monzogranitic rocks from the region of Novo Oriente in the southern portion of the Ceara Central Domain. In this area the granitoids are weakly peraluminous biotite granitoids and deformed biotite granitoids of high-K calc-alkaline and ferroan composition, which we interpreted as primary magmas (segregated diatexites) derived from the partial melting of crustal material. The close temporal relation of this magmatism with local eclogitic and regional high temperature metamorphism in Ceara Central Domain point out to an orogenic setting, arguably emplaced during the collisional stage. Subordinate coeval juvenile mantle incursions are also present. This crustally derived magmatism is the primary product of the continental thickening that resulted from the collision between the rocks represented by the Amazonian-West African craton (Sao Luiz cratonic fragment) to the northwest and the Paleoproterozoic-Archean basement of the Borborema Province to the southeast along the Transbrasiliano tectonic corridor. (C) 2011 Elsevier Ltd. All rights reserved.

Geochronological constraints on the age of a Permo-Triassic impact event: U-Pb and Ar-40/Ar-39 results for the 40 km Araguainha structure of central Brazil

Impact cratering has been a fundamental geological process in Earth history with major ramifications for the biosphere. The complexity of shocked and melted rocks within impact structures presents difficulties for accurate and precise radiogenic isotope age determination, hampering the assessment of the effects of an individual event in the geological record. We demonstrate the utility of a multi-chronometer approach in our study of samples from the 40 km diameter Araguainha impact structure of central Brazil. Samples of uplifted basement granite display abundant evidence of shock deformation, but U/Pb ages of shocked zircons and the Ar-40/Ar-39 ages of feldspar from the granite largely preserve the igneous crystallization and cooling history. Mixed results are obtained from in situ Ar-40/Ar-39 spot analyses of shocked igneous biotites in the granite, with deformation along kink-bands resulting in highly localized, partial resetting in these grains. Likewise, spot analyses of perlitic glass from pseudotachylitic breccia samples reflect a combination of argon inheritance from wall rock material, the age of the glass itself, and post-impact devitrification. The timing of crater formation is better assessed using samples of impact-generated melt rock where isotopic resetting is associated with textural evidence of melting and in situ crystallization. Granular aggregates of neocrystallized zircon form a cluster of ten U-Pb ages that yield a "Concordia" age of 247.8 +/- 3.8 Ma. The possibility of Pb loss from this population suggests that this is a minimum age for the impact event. The best evidence for the age of the impact comes from the U-Th-Pb dating of neocrystallized monazite and Ar-40/Ar-39 step heating of three separate populations of post-impact, inclusion-rich quartz grains that are derived from the infill of miarolitic cavities. The Pb-206/U-238 age of 254.5 +/- 3.2 Ma (2 sigma error) and Pb-208/Th-232 age of 255.2 +/- 4.8 Ma (2 sigma error) of monazite, together with the inverse, 18 point isochron age of 254 +/- 10 Ma (MSWD = 0.52) for the inclusion-rich quartz grains yield a weighted mean age of 254.7 +/- 2.5 Ma (0.99%, 2 sigma error) for the impact event. The age of the Araguainha crater overlaps with the timing of the Permo-Triassic boundary, within error, but the calculated energy released by the Araguainha impact is insufficient to be a direct cause of the global mass extinction. However, the regional effects of the Araguainha impact event in the Parana-Karoo Basin may have been substantial. (C) 2012 Elsevier Ltd. All rights reserved.

G'day Gondwana - the final accretion of a supercontinent: U-Pb ages from the post-orogenic Sao Vicente Granite, northern Paraguay Belt, Brazil

The Paraguay Belt in central South America is part of a larger chain of orogenic belts, including the Araguaia Belt to the northeast and potentially the Pampean Belt to the south, which are believed to mark the suture zone of the Clymene Ocean - interpreted amongst the youngest of the Gondwana amalgamation orogens. The post-orogenic Sao Vicente Granite crops out in the northern Paraguay Belt and cuts the basal unit of the deformed and metamorphosed Cuiaba Group. The age of this granite therefore provides a long sort after minimum age for orogenesis within the belt. Dating crystallisation of this important intrusion is challenging due to the presence of considerable common-Pb. However, based on LA-ICPMS dating of more than 100 zircons from three separate samples we interpret a robust crystallisation age for the Sao Vicente batholith at 518 +/- 4 Ma. This age constrains the termination of deformation within the Paraguay Belt and the final accretion of the supercontinent Gondwana. (C) 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Reproductive biology of the ghost shrimp Lepidophthalmus bocourti (A. Milne-Edwards, 1870) (Decapoda: Axiidea: Callianassidae): A tropical species with a seasonal reproduction

Based on the hypothesis that reproduction is a continuous process in tropical habitats, we analysed reproductive periodicity and egg production in the callianassid ghost shrimp Lepidophthalmus bocourti, one of the most common species in mangrove systems along the Pacific coast of Central America. During one year (May 2008 to April 2009), individuals of L. bocourti (N = 499) were collected nearshore Gulf of Nicoya, Pacific coast of Costa Rica. Observations were made on presence or absence of incubated embryos, and gonad activity of females was analysed as gonadosomatic index (GSI). Our results revealed that L. bocourti has a marked seasonal breeding period, which contradicts previous reports regarding coastal marine decapods from the tropics. Ovigerous females were found only from June to August, while high GSI values were obtained from March to July. The increase of GSI and appearance of ovigerous females were associated with a concomitant decrease of salinity, but not with temperature. We assume that reproduction of L. bocourti is adapted to local changes of environmental conditions, and that a decrease in salinity during rainy season may serve as a triggering factor for ovarian development. Compared to other ghost shrimps, L. bocourti produced on average more (2002 +/- 1365) and smaller (0.87 +/- 0.109 mm) eggs, which seems to suggest that this species does not have an abbreviated larval development as reported for other species of genus. The deviation from the generalization of constant reproduction in the tropics for shallow water marine invertebrates and its probable cause are adequately discussed.

TL dating of pottery fragments from four archaeological sites in Taquari Valley, Brazil

Sixty-three pottery fragments from four archaeological sites, numbered RST110, RST101, RST114 and RST114, in the Taquari Valley, vicinity of the city of Lajeado, Rio Grande do Sul state, southern Brazil, have been dated by the thermoluminescence method. Some of them from RST110 and RST101 are as old as 1400-1200 years, whereas those from RST114 and RST107 are younger than 800 years. This result indicates that RST101 and RST110 were peopled earlier than RST114 and RST107. The recent dates found are 302, 295 and 146 years and they are possible, since the first German immigrants who arrived in this region encountered Tupi-Guarani Indians still living there. One interesting result refers to the glow curves of quartz grains RST110, RST101 and RST114 that differ from the glow curves of RST107 quartz grains.

Signaling Events During Cyclic Guanosine Monophosphate-Regulated Pigment Aggregation in Freshwater Shrimp Chromatophores

Crustacean color change results partly from granule aggregation induced by red pigment concentrating hormone (RPCH). In shrimp chromatophores, both the cyclic GMP (3', 5'-guanosine monophosphate) and Ca2+ cascades mediate pigment aggregation. However, the signaling elements upstream and downstream from cGMP synthesis by GC-S (cytosolic guanylyl cyclase) remain obscure. We investigate post-RPCH binding events in perfused red ovarian chromatophores to disclose the steps modulating cGMP concentration, which regulates granule translocation. The inhibition of calcium/calmodulin complex (Ca2+/CaM) by N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide (W7) induces spontaneous aggregation but inhibits RPCH-triggered aggregation, suggesting a role in pigment aggregation and dispersion. Nitric oxide synthase inhibition by N omega-nitro-L-arginine methyl ester hydrochloride (L-NAME) strongly diminishes RPCH-induced aggregation; protein kinase G inhibition (by rp-cGMPs-triethylamine) reduces RPCH-triggered aggregation and provokes spontaneous dispersion, disclosing NO/PKG participation in aggregation signaling. Myosin light chain phosphatase inhibition (by cantharidin) accelerates RPCH-triggered aggregation, whereas Rho-associated protein kinase inhibition (by Y-27632, H-11522) reduces RPCH-induced aggregation and accelerates dispersion. MLCP (myosin light chain kinase) and ROCK (Rho-associated protein kinase) may antagonistically regulate myosin light chain (MLC) dephosphorylation/phosphorylation during pigment dispersion/aggregation. We propose the following general hypothesis for the cGMP/Ca2+ cascades that regulate pigment aggregation in crustacean chromatophores: RPCH binding increases Ca2+ (int), activating the Ca2+/CaM complex, releasing NOS-produced nitric oxide, and causing GC-S to synthesize cGMP that activates PKG, which phosphorylates an MLC activation site. Myosin motor activity is initiated by phosphorylation of an MLC regulatory site by ROCK activity and terminated by MLCP-mediated dephosphorylation. Qualitative comparison reveals that this signaling pathway is conserved in vertebrate and invertebrate chromatophores alike.

A novel spermatozoan ultrastructure in the shrimp Hippolyte obliquimanus Dana, 1852 (Decapoda: Caridea: Hippolytidae)

The aim of this study was to describe and illustrate the morphology of the spermatozoon of the Western Atlantic shrimp, Hippolyte obliquimanus. Individuals were sampled from Itagua Beach (Ubatuba, southern Brazil). The male reproductive system was dissected and morphological analysis was undertaken using a stereomicroscope, a light microscope, and transmission electron and scanning electron microscopes. When viewed from the nuclear or acrosomal poles, each spermatozoon has many translucent radiating arms (about 20) from a denser cell body, while laterally the cell body and arms resemble a "cnidarian medusa", with all the arms projecting away from the bell-like cell body. This sperm morphology is distinct from the "thumbtack"-shaped spermatozoa observed in the majority of carideans but has similarities to the spermatozoa of Rhynchocinetes spp. The morphology of sperm of several species of the genus Hippolyte resembles the spermatozoon of H. obliquimanus with the presence of posterior nuclear arms, but it is necessary to study other Hippolyte species to place these arms in the context of the genus.

Assessment of trophic transfer of benzo(a)pyrene genotoxicity from the post-larval pink shrimp F. brasiliensis to the juvenile Florida pompano T. carolinus

In the present study, the polycyclic aromatic hydrocarbon (PAH) genotoxicity was investigated in a one-step predator-prey relationship with the trophic-related marine species. Florida pompanos were fed for 5 and 10 days with pink shrimp post larvae previously exposed to benzo(a)pyrene (BaP) concentrations. Parent BaP body burden was measured in samples of Farfantepenaeus brasiliensis. BaP metabolites were determined in bile samples of Trachinotus carolinus and DNA damage was assessed through the comet and erythrocyte nuclear abnormalities (ENAs) assays in fish erythrocytes. BaP body burden increased significantly with the PAH concentration in pink shrimp PLs as well as the fish bile BaP metabolites. Both, comet and ENAs assays indicated significant increase on erythrocyte DNA damage of Florida pompanos fed with BaP-exposed pink shrimp on both feeding periods. The trophic route of BaP genotoxicity is discussed as well as the PAH biotransformation as the inducing mechanism for the DNA damages observed.

EROD activity and genotoxicity in the seabob shrimp Xiphopenaeus kroyeri exposed to benzo[a]pyrene (BaP) concentrations

Seabob shrimp Xiphopenaeus kroyeri is a marine species that lives in shallow waters of coastal environments, often impacted by polycyclic aromatic hydrocarbons (PAH) pollution. In the present study, seabob shrimp were exposed for 96 h to benzo[a]pyrene (BaP) at the nominal concentrations of 100, 200, 400 and 800 microg.L-1. Animals of the control groups were exposed either to clean water or to the BaP-carrier (DMSO). At the end of the exposures, muscle tissues were sampled for BaP uptake assessment and hepatopancreas and hemolymph for EROD enzyme activity and hemocytes DNA damage, respectively. EROD activity and DNA damage increased significantly as a function of BaP exposure concentrations. Significant correlations between BaP uptake and both EROD activity and DNA damage suggest that they can be used as suitable tools for integrated levels of study on the biomarkers of PAH exposure.

Ontogenetic and evolutionary change of external morphology of the neotropical shrimp potimirim (Holthuis, 1954) explained by a molecular phylogeny of the genus

A phylogenetic analysis of a fragment of the mitochondrial gene 16S was used to test the monophyletic status of Potimirim. Existing doubts on the taxonomic status of brasiliana (once P glabra) and P potimirim (once P mexicana) were clarified. Potimirim mexicana and P potimirim are distinct species according to molecular data and appendix masculina morphology. A new species (Potimirim sp. 1) from Puerto Rico was revealed with molecular data, and it is evolutionarily related to P potimirim and P mexicana according to our analysis. We found out three distinct species under the name P glabra. Then, we recommend the application of the name P glabra for the populations of the Pacific slope of Central America and revalidation of P brasiliana for the Brazilian ones. The need for a new name to those "P glabra" of the Caribbean is highlighted, and it was provisionally referred as Potimirim sp. 2. The ontogenetic (juveniles to adults) development of the appendix masculina of P brasiliana was observed and compared to the other species of Potimirim (adults). In the light of our phylogenetic hypothesis, we postulate a pattern of character addition for the evolution of the appendix masculina of Potimirim. This hypothesis is plausible for two key reasons. First. Potimirim is a monophyletic group according to our hypothesis. Second, the shape of appendix masculina found in adults of P. americana is similar and comparable to those found in the earliest juvenile stages of P brasiliana, a derived species according to our phylogeny (P americana, ((P mexicana, Potimirim sp. 1. P potimirim), (P glabra, (brasiliana, Potimirim sp. 2)))). As so, the basal P americana retain the ancestral morphological state of the appendix masculina when compared to the other species of Potimirim. In our interpretation the ontogeny of the appendix masculina recapitulated the proposed phylogeny, giving further support to it.

The growth of large mafic intrusions: Comparing Niquelandia and Ivrea igneous complexes

The Niquelandia Complex, Brazil, is one of the world's largest mafic-ultramafic plutonic complexes. Like the Mafic Complex of the Ivrea-Verbano Zone, it is affected by a pervasive high-T foliation and shows hypersolidus deformation structures, contains significant inclusions of country-rock paragneiss, and is subdivided into a Lower and an Upper Complex. In this paper, we present new SHRIMP U-Pb zircon ages that provide compelling evidence that the Upper and the Lower Niquelandia Complexes formed during the same igneous event at ca. 790 Ma. Coexistence of syn-magmatic and high-T subsolidus deformation structures indicates that both complexes grew incrementally as large crystal mush bodies which were continuously stretched while fed by pulses of fresh magma. Syn-magmatic recrystallization during this deformation resulted in textures and structures which, although appearing metamorphic, are not ascribable to post-magmatic metamorphic event(s), but are instead characteristic of the growth process in huge and deep mafic intrusions such as both the Niquelandia and Ivrea Complexes. Melting of incorporated country-rock paragneiss continued producing hybrid rocks during the last, vanishing stages of magmatic crystallization. This resulted in the formation of minor, late-stage hybrid rocks, whose presence obscures the record of the main processes of interaction between mantle magmas and crustal components, which may be active at the peak of the igneous events and lead to the generation of eruptible hybrid magmas. (C) 2012 Elsevier B.V. All rights reserved.

Neoproterozoic glacial deposits from the Aracuai orogen, Brazil: Age, provenance and correlations with the Sao Francisco craton and West Congo belt

Glacigenic diamictite successions of the Macaubas Group are widespread in the western domain of the Aracuai orogen, east of the Sao Francisco craton (Brazil). Diamictites also occur on this craton and in the African counterpart of the Aracuai orogen, the West Congo belt. Detrital zircon grains from the matrix of diamictites and sandstones from the Macaubas Group were dated by the U-Pb SHRIMP technique. The geochronological study sets the maximum depositional age of the glacial diamictites at 900 Ma, and indicates multiple sources for the Macaubas basin with ages ranging from 900 to 2800 Ma. Sm-Nd T-DM model ages, determined on whole rock samples, range from 1.8 Ga to 2.5 Ga and get older up-section. Comparison of our data with those from the cratonic area suggest that these glacial deposits can be correlated to the Jequitai and Carrancas diamictites in the Sao Francisco craton, and to the Lower Mixtite Formation of the West Congolian Group, exposed in Africa. The 900-1000 Ma source is most probably represented by the Zadinian-Mayumbian volcanic rocks and related granites from the West Congo belt. However, one of the most voluminous sources, with ages in the 1.1-1.3 Ga interval, has not been detected in the Sao Francisco-Congo craton. Possible sources for these grains could occur elsewhere in Africa, or possibly from within the Brasilia Belt in western central Brazil. (C) 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.