Embryos of common thresher shark Alopias vulpinus in southern Brazil, south Atlantic Ocean

Eight embryonic thresher sharks Alopias vulpinus (53.9-124 cm total length) were collected from two females caught by commercial longline off southern Brazil in September and November 2004. Morphometric measurements are provided. (c) 2006 the Authors.

Biogeography of common dolphins (genus Delphinus) in the Southwestern Atlantic Ocean

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

South Atlantic Ocean cyclogenesis climatology simulated by regional climate model (RegCM3)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Recognition of Cretaceous, Paleocene, and Neogene tectonic reactivation through apatite fission-track analysis in Precambrian areas of southeast Brazil: Association with the opening of the south Atlantic Ocean

Apatite fission-track analysis was used for the determination of thermal histories and ages in Precambrian areas of southeast Brazil. Together with geological and geomorphologic information, these ages enable us to quantify the thermal histories and timing of Mesozoic and Cenozoic epirogenic and tectonic processes. The collected samples are from different geomorphologic blocks: the high Mantiqueira mountain range (HMMR) with altitude above 1000 m, the low Mantiqueira mountain range (LMMR) under 1000 m, the Serra do Mar mountain range (SMMR), the Jundiá and Atlantic Plateaus, and the coastline, all of which have distinct thermal histories. During the Aptian (∼120 Ma), there was an uplift of the HMMR, coincident with opening of the south Atlantic Ocean. Its thermal history indicates heating (from ∼60 to∼80 °C) until the Paleocene, when rocks currently exposed in the LMMR reached temperatures of ∼100 °C. In this period, the Serra do Mar rift system and the Japi erosion surface were formed. The relief records the latter. During the Late Cretaceous, the SMMR was uplifted and probably linked to its origin; in the Tertiary, it experienced heating from ∼60 to ∼90 °C, then cooling that extends to the present. The SMMR, LMMR, and HMMR were reactivated mainly in the Paleocene, and the coastline during the Paleogene. These processes are reflected in the sedimentary sequences and discordances of the interior and continental margin basins. © 2002 Elsevier Science Ltd. All rights reserved.

Length-weight relationships, condition and population structure of the genus Atlantoraja (Elasmobranchii, Rajidae, Arhynchobatinae) in Southeastern Brazilian waters, SW Atlantic Ocean

During the present study, 107 specimens of Atlantoraja castelnaui, 188 of A. platana, and 770 of A. cyclophora, were obtained by commercial vessels operating in Southeastern Brazil from March 2005 to April 2006. Males of A. castelnaui ranged from 17.9-111.0 cm and females from 17.4-116.0 cm total length. Males of A. platana ranged from 13.1-70.0 cm and females from 12.5-76.0 cm total length. Males of A. cyclophora ranged from 13.3-58.5 cm and females from 11.5-68.0 cm total length. Length-weight curves were sexually dimorphic in the three species. The analysis of the angular coefficient (b) demonstrated that growth (in weight) in relation to length was allometric (b>3) in males of A. castelnaui and A. platana, while isometric (b = 3) in females of these species. Conversely, growth of A. cyclphora was isometric in males, while in females it was allometric (b>3). The condition factor varied significantly throughout the year only in females of A. castelnaui.

The reproductive biology and cycle of Rioraja agassizi (Müller and Henle, 1841) (Chondrichthyes: Rajidae) in southeastern Brazil, SW Atlantic Ocean

Specimens of Rioraja agassizi were collected at Guarujá pier, São Paulo State, Brazil, from March 2005 to March 2006. A total of 275 males were captured. Based on the analysis of the clasper length, gonad weight, clasper gland length, alar thorns and lobule diameter, the size-at-maturity was estimated to be 32 cm. There were 1049 females in the record. Size-at-maturity was calculated in 40 cm. Sexual resting females were observed. Gonadosomatic and hepatosomatic indexes varied significantly in both sexes throughout the year. However, ovulation, egg-laying and presence of sperm in the seminal vesicle were observed all year round. For this reason, an annual cycle with at least one peak in the sexual activity is proposed for this species.

Evolução da margem atlântica equatorial do Brasil: Três fases distensivas

The extension of the Pangaea started in the Upper Triassic and evolved to uplifts, magmatism and development a triple junction during the Mesozoic, and opening the Central Atlantic Ocean. The Brazilian Equatorial Atlantic margin was formed in three Mesozoic extensional events. The first event is recorded by the Calçoene Graben of the Foz do Amazonas Basin. The second event started in the Valangian and is recognized by the enlargement of the Foz do Amazonas Basin, formation of the Marajó and Grajaú basins, and the Gurupi Graben System. The third event commenced in the Albian related to northwestward progression of the rift system, which enlarged the Foz do Amazonas and formed the Potiguar, Ceará, Barreirinhas and Pará-Maranhão basins. At the end of the Lower Cretaceous the movements attenuated in the Marajó Basin and Gurupi Graben System; the extension concentrated in the Foz do Amazonas, Pará-Maranhão and Barreirinhas basins, and evolved to continental rupture of northern South America and western Africa opening of the Equatorial Atlantic Ocean.

Evolução do rifteamento e paleogeografia da margem Atlântica Equatorial do Brasil: Triássico ao Holoceno

The Equatorial Atlantic Margin evolved from three rift systems recorded by a complex set of sedimentary basins developed since Upper Triassic to the Lower Cretaceous (Albian). The first rift system formed Foz do Amazonas Basin in Upper Triassic; the second phase formed Marajó Basin in Berriasian, a new rift in Foz do Amazonas Basin in Valanginian and Bragança-Viseu, Ilha Nova, São Luís e Barreirinhas basins in Aptian; the third phase formed Barreirinhas and Pará- Maranhão basins and a new rifting in the Foz do Amazonas Basin between the Aptian and Albian and evolved to continental break up. The main paleostress field during rift evolution was NE-SW and after the continental break up took the E-W direction, from the development of transform zones in the oceanic crust. From Miocene, South America was subjected to intraplate tectonics, which resulted in formation of E-W transcurrent faults that generated transtensive and transpressive segments that formed sedimentary basins and hills, resulting in changes in the drainage network. In Quaternary the landscape was modified by the last ice age that changed the sea level; the coastal drainage network was drowning resulting in the formation of the current line coast.

Local and regional features of surface radiation fluxes over the tropical Atlantic ocean near Sao Pedro and Sao Paulo archipelago: Evidence of small scale upwelling

To properly describe the interactions between the ocean and atmosphere, it is necessary to assess a variety of time and spatial scales phenomena. Here, high resolution oceanographic and meteorological data collected during an observational campaign carried out aboard a ship in the tropical Atlantic Ocean, on May 15-24, 2002, is used to describe the radiation balance at the ocean interface. Data collected by two PIRATA buoys, along the equator at 23°W and 35°W and satellite and climate data are compared with the data obtained during the observational campaign. Comparison indicates remarkable similarity for daily and hourly values of radiation fluxes components as consequence of the temporal and spatial consistence presented by the air and water temperatures measured in situ and estimated from large scale information. The discrepancy, mainly in the Sao Pedro and Sao Paulo Archipelago area, seems to be associated to the local upwelling of cold water, which is not detected in all other estimates investigated here. More in situ data are necessary to clarify whether this upwelling flow has a larger scale effect and what are the meteorological and oceanographic implications of the local upwelling area on the tropical waters at the Brazilian coast.

Reproductive biology of the guitarfish Rhinobatos percellens (Chondrichthyes, Rhinobatidae) from the São Paulo Coast, Brazil, western South Atlantic Ocean

The reproductive biology of the guitarfish Rhinobatos percellens was studied from 751 specimens caught by bottom pair trawlers off the coast of São Paulo, Brazil, between c. 24° 00′ S; 45° 15′ W and c. 25° 10′ S; 47° 52′ W, from September 2007 to August 2009. The total length (LT) and total mass (MT) relationship for males and females combined was MT = 1·29E-06 LT 3·15 (r = 0·99, n = 751). The mean LT of sexually mature specimens was 548 mm for males and 583 mm for females. Clasper growth was allometric and showed three distinct phases. Most claspers were calcified in specimens of c. 550 mm LT. The mean diameter of the largest oocyte was 29·8 mm, the mean ovarian fecundity was seven oocytes and ovulation occurred between August and November. Uterine fecundity ranged from two to 13 embryos (mean of five embryos). Larger females had higher litter sizes and larger embryos; the size-at-birth was c. 200 mm LT. The hepato-somatic index oscillated seasonally for males and females; the gonado-somatic index had little variation in males, but varied seasonally in females. The presence of many non-pregnant adult females and of encapsulated eggs during two consecutive seasons suggests a resting period between gestations and the possibility of diapause. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Sazonalidade da precipitação para a Amazônia usando o modelo REGCM3: avaliando apenas a forçante do Atlântico Equatorial

O presente estudo tenta trazer um novo ponto de vista sobre a importância do Oceano Atlântico Equatorial no padrão sazonal, durante o período de verão e de outono da região Amazônica. Desta maneira, contribui de uma forma diferente para os estudos na área de modelagem climática e variabilidade pluviométrica na região. Para isto, foi utilizado o modelo RegCM3, com esquema de convecção Grell, aplicando a técnica donwscaling e utilizando como condição inicial os dados de reanalise do NCEP/NCAR. Após a obtenção das simulações foi aplicado o método estatístico Viés para avaliar o quanto o modelo consegue reproduzir a precipitação sazonal. Em uma primeira análise, constata-se que o modelo é sensível a entrada de SF ou ZCAS, bem como, aproxima-se da dinâmica dos trópicos e extratropicos. Os resultados sugerem que a baixa resolução e a parametrização Grell são os principais fatores para a inadequação da qualidade das simulações. Apesar de o esquema Grell ser indicado para regiões com intensa convecção e fortes movimentos verticais, o mesmo necessita ser ajustado com as características físicas da região. Este estudo contribuiu para o aprimoramento dos modelos climáticos regionais para a região amazônica, considerando a contribuição dos processos oceano-atmosfera, durante o período de verão e outono do hemisfério sul.

Clypeina tibanai, sp. nov. (Polyphysacea, Dasycladales, Chlorophyta), mid-Cretaceous green alga from the Potiguar Basin, Brazilian margin of the young South Atlantic Ocean

The fossil genus Clypeina (Michelin, 1845) comprises some 40 species. We describe Clypeina tibanai, a new species from ? upper Albian-Cenomanian strata of the Potiguar Basin, Brazil, characterised by closely set verticils of tubular, bended laterals. It is compared with Clypeina hanabataensis Yabe & Toyama, 1949, a Late Jurassic species, and with Pseudoactinoporella fragilis (Conrad, 1970), an Early Cretaceous taxon. The new species belongs to a short list of green algae found in the young South Atlantic oceanic corridor, an assemblage defining a phycological paleobioprovince discrete from that of the Tethyan realm.

Bayesian age and growth analysis of the shortfin mako shark Isurus oxyrinchus in the Western South Atlantic Ocean using a flexible model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Five new records of Luvarus imperialis (Acanthuroidei: Luvaridae) in the south-west Atlantic Ocean

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Historical Observations of Humpback And Blue Whales in the North Atlantic Ocean: Clues to Migratory Routes and Possibly Additional Feeding Grounds

The seasonal distributions of humpback and blue whales (Megaptera novaeangliae and Balaenoptera musculus, respectively) in the North Atlantic Ocean are not fully understood. Although humpbacks have been studied intensively in nearshore or coastal feeding and breeding areas, their migratory movements between these areas have been largely inferred. Blue whales have only been studied intensively along the north shore of the Gulf of St. Lawrence, and their seasonal occurrence and movements elsewhere in the North Atlantic are poorly known. We investigated the historical seasonal distributions of these two species using sighting and catch data extracted from American 18th and 19th century whaling logbooks. These data suggest that humpback whales migrated seasonally from low-latitude calving/ breeding grounds over a protracted period, and that some of them traveled far offshore rather than following coastal routes. Also, at least some humpbacks apparently fed early in the summer west of the Mid-Atlantic Ridge, well south of their known present-day feeding grounds. In assessing the present status of the North Atlantic humpback population, it will be important to determine whether such offshore feeding does in fact occur. Blue whales were present across the southern half of the North Atlantic during the autumn and winter months, and farther north in spring and summer, but we had too few data points to support inferences about these whales’ migratory timing and routes.