Resumo Objetivo O semiárido tropical brasileiro é um bioma que possui pequenos ecossistemas de água doce, frequentemente intermitentes, que atuam como um mosaico em constante transformação entre as estações seca e chuvosa. As comunidades meiobentônicas desempenham papéis cruciais nesses ambientes, e compreender seus processos de colonização e sucessão é fundamental para entender como esses organismos se estruturam em um habitat defaunado. Além da abordagem taxonômica tradicional, os traços funcionais oferecem perspectivas valiosas sobre a dinâmica desses processos. Neste estudo, testamos as seguintes hipóteses: i) embora a meiofauna seja composta por organismos microscópicos com dispersão ativa limitada, eles colonizam rapidamente novos substratos, aumentando em abundância, riqueza e diversidade; ii) as características funcionais dos Nematoda de água doce são uma boa ferramenta para observar uma sucessão inicial em substrato artificial duro em um reservatório lêntico. Métodos Colocamos 27 placas de cerâmica em um reservatório no semiárido brasileiro e amostramos aleatoriamente três réplicas a cada semana, ao longo de nove semanas. As diferenças semanais na abundância, riqueza e diversidade da comunidade foram testadas com one-way ANOVA e pairwise PERMANOVA. Resultados Os Nematoda predominaram na primeira semana, com os Rotifera dominando a partir da segunda semana de experimento. Não observamos diferenças na estrutura taxonômica da comunidade de Nematoda ao longo das semanas. Entretanto, houve um aumento na complexidade funcional da comunidade de Nematoda ao longo do tempo, conforme indicado pelo índice de maturidade e pela estrutura trófica. Os colonizadores/persistentes surgiram rapidamente na primeira semana. Os comedores de depósito dominaram, mas observou-se um aumento na diversidade trófica com a presença crescente dos mastigadores ao longo das semanas. Conclusões Este estudo destaca que as características funcionais dos Nematoda representam uma ferramenta robusta para avaliar a sucessão ecológica em ambientes lênticos de água doce no semiárido tropical. intermitentes chuvosa defaunado tradicional hipóteses i limitada substratos abundância ii lêntico 2 semanas oneway one way PERMANOVA experimento Entretanto tempo colonizadorespersistentes colonizadores persistentes dominaram observouse observou

Abstract Aim The Brazilian tropical semiarid is a biome with small freshwater ecosystems, often intermittent, acting as a mosaic in constant transformation between dry and rainy seasons. Meiobenthic communities play crucial roles in these environments, and understanding their colonization and succession processes is essential to comprehend how these organisms’ structure in a defaunated habitat. In addition to the traditional taxonomic approach, functional traits provide valuable insights into the dynamics of these processes. In this study, we tested the following hypotheses: i) although meiofauna consists of microscopic organisms with limited active dispersion, they quickly colonize new substrates, increasing in abundance, richness, and diversity; ii) functional traits of freshwater Nematoda are a good tool for view an early succession on hard artificial substrate in a lentic reservoir. Methods We placed 27 ceramic plates in a reservoir in the Brazilian semiarid and randomly sampled three replicates each week over nine weeks. Weekly differences in community abundance, richness, and diversity were tested with one-way ANOVA and pairwise PERMANOVA. Results Nematoda predominated in the first week, with Rotifera taking over from the second week of the experiment. No differences were observed in the Nematode taxonomic structure over the weeks. There was an increase in the functional complexity of the Nematoda community over time, as indicated by the maturity index and trophic structure. Colonizers/persistents emerged quickly in the first week. Deposit feeders dominated, but an increase in trophic diversity was observed with the growing presence of chewers over the weeks. Conclusions This study highlights that the functional traits of Nematoda represent a robust tool for assessing ecological succession in freshwater lentic environments in the tropical semiarid. ecosystems intermittent seasons habitat approach hypotheses i dispersion substrates abundance richness ii 2 weeks oneway one way PERMANOVA experiment time Colonizerspersistents Colonizers persistents dominated

ABSTRACT We provide the first record of the giant deep-sea jellyfish Stygiomedusa gigantea (Browne, 1910) from the tropical Southwestern Atlantic, based on a posting made on social media. The image was found during data filtering through the hashtag #aguavivagigante (in English, #giantjellyfish) on Instagram. The jellyfish was seen floating motionless at the surface, presumed dead, off Bahia, Northeast Brazil (12°34’39”S; 38°00’19”W), on August 23rd, 2016. Pygmy killer whales, Feresa attenuata Gray, 1874, were observed in the intermediate area and apparently interacting with the jellyfish. Observations of S. gigantea usually come from submersibles and ROVs. This is the first record extracted from social media, highlighting its potential use to complement information based on traditional scientific methods, and expanding the known geographic distribution of jellyfish. With the growth and development of social media in the coming years, we highlight its potential as a data source from citizen science. We also expect that social media will increasingly contribute to the knowledge of remarkable but poorly known species such as S. gigantea. deepsea deep sea Browne, Browne (Browne 1910 Atlantic aguavivagigante English #giantjellyfish giantjellyfish Instagram surface dead Bahia 12°3439S 123439S S 12°34 39 12 34 (12°34’39”S 38°0019W, 380019W W 38°00 19 , 38 00 38°00’19”W) 23rd rd 2016 whales Gray 1874 ROVs methods years science 191 3439S 1234 12°3 3 1 0019W 38°0019W 3800 38°0 0 38°00’19”W 201 187 123 12° 380 38° 20 18 2

ABSTRACT The aim of the present study was to investigate the effect of dredging activities on the structure of the macrobenthic community of a port complex in São Luís do Maranhão (2°S, Brazil). Sampling was performed on four occasions: pre-dredging, dredging 1 (25% of the material dredged), dredging 2 (75% of the material dredged) and post-dredging. Total mean density was 430.8 ± 55.0 ind/m², with 147.76 ± 280.82 ind/m² at pre-dredging, 161.90 ± 285.67 ind/m² at dredging 1, 53.83 ± 72.15 ind/m² at dredging 2 and 67.29 ± 72.58 ind/m² after dredging, revealing a reduction during dredging 2. The most representative groups were Polychaeta, Oligochaeta, Crustacea and Mollusca. Lumbrineris sp. (Polychaeta) was present in all sampling periods and was the dominant species. Richness and Shannon diversity of the species were higher in the pre-dredging and post-dredging periods, with reductions during the dredging activities (dredging 1 and 2). Principal component analysis revealed a correlation with granulometry and heavy metals in the sediment. The dredging activities led to a reduction in the macrobenthic community. Moreover, post-dredging recovery was insufficient for the recovery of the community. 2°S, 2S S (2°S Brazil. Brazil . Brazil) occasions predredging, predredging pre 25% 25 (25 dredged, dredged , 75% 75 (75 postdredging. postdredging post dredging. 4308 430 8 430. 550 55 0 55. indm² indm ind m² m 14776 147 76 147.7 28082 280 82 280.8 ind/m 16190 161 90 161.9 28567 285 67 285.6 5383 53 83 53.8 7215 72 15 72.1 6729 29 67.2 7258 58 72.5 Polychaeta Oligochaeta Mollusca sp (Polychaeta 2) sediment Moreover 2°S (2 7 (7 43 5 1477 14 147. 2808 28 280. 1619 16 9 161. 2856 6 285. 538 53. 721 72. 672 67. 725 ( 4

Resumo: Objetivo Esse trabalho relata a ocorrência de gêneros de Nematoda, que eram previamente considerados restritos a ambientes marinhos, em águas continentais. Métodos Amostras de sedimentos foram coletadas semanalmente, durante nove semanas, entre março e maio de 2016 no Horto Florestal Olho D’Água da Bica, Cuité, PB, cerca de 130 km da região costeira mais próxima e fixados em formol 4%. Os Nematoda foram separados por elutriação manual através de peneira de malha de 0,5 e 0,045 mm e lâminas foram confeccionadas. Resultados O sedimento foi classificado como areia grossa, com teor de matéria orgânica variando entre 2,73 e 13,32%, temperatura entre 27-28°C e salinidade constante de 6. Dentre 315 nematoides coletados, 18 são de cinco gêneros marinhos. Bolbolaimus foi o mais frequente, presente em 11,1% das amostras, seguido de Gomphionema (3,7%), Rynchonema (7,4%), Prorynchonema (7,4%) e Sabatieria (3,7%), representando 5,7% do total da nematofauna. Esses gêneros têm ampla distribuição no mundo, mas não possuem registros prévios em ambientes continentais, sendo a primeira ocorrência nesse estudo. Conclusões Este trabalho contribui com o conhecimento da distribuição de Nematoda de vida livre. De acordo com os dados de literatura, esses gêneros não possuem restrições a baixas salinidades, sendo encontrados em regiões estuarinas e/ou águas salobras e também em corpos de água doce com conexão direta com o mar. Ainda assim, é notável a presença de gêneros marinhos há ~130 km de distância da costa, enfatizando a importância de estudos em diferentes corpos d’água no semiárido, permitindo questionar sobre quais mecanismos de dispersão permitiram esses indivíduos colonizar essa região.

Abstract: Aim This study reports the occurrence of five Nematoda genera previously considered as exclusively marine in inland waters. Methods Sediment samples were taken, weekly, during nine weeks, at a small spring at the Horto Florestal Olho D’Água da Bica, Cuité, PB, ca. 130 km away from the shoreline, between March and May 2016 and fixed in 4% formalin. Nematodes were sorted by manual elutriation through sieves with 0.5 and 0.045 mm and slides were prepared. Results The sediment was classified as coarse sand, with organic matter content ranging between 2.73 and 13.32%, temperature between 27-28°C and constant salinity of 6. From 315 nematodes were sampled among which 18 were from five genera previously thought to be exclusively marine were found. Bolbolaimus was the most common, found in 11.1% of the samples, followed by Gomphionema (3.7%), Rynchonema (7.4%), Prorynchonema (7.4%) e Sabatieria (3.7%), representing 5.7% from total of nematofauna. These genera are widely distributed worldwide, but had never been recorded from inland environments. Conclusions This study contributes with the distributional knowledge of free-living nematodes. From literature data, these genera are not restricted by low salinity, and can be found in estuarine and/or brackish water environments and body water with direct connection to the sea. In any case, the presence of marine genera in this region which is >130 km away from the nearest shoreline is noteworthy, highlighting the importance of studying nematodes from these poorly known semiarid water bodies. These new occurrences raise questionings about the dispersal mechanisms that certified the colonization of these nematodes in the semiarid.

Abstract The horizontal distribution of plankton communities in a subtropical mixed estuarine system over one tidal cycle was investigated. Hydrological and planktonic samples were obtained twice on 17 July 2007 in a transect with ten stations in the Babitonga Bay estuary, south Brazil (~26°S). Hydrological variables did not vary spatially or tidally during samplings. However, in the cluster analyses both phyto and zooplankton were structured according to their estuarine position and in the inner stations also by the tidal condition. Phytoplankton abundances were higher during flood tide in the inner estuary (max. 122,583 ind.L-1), where diatoms dominated, particularly Diploneis bombus. However, the density at ebb tide increased towards outer estuary (max. >100,000 ind.L-1) and flagellates, mostly Gymnodinium spp., became abundant. Zooplankton abundances were higher at intermediate stations during both tides (max. 13,691 ind.m-3). The innermost stations were dominated by the copepod Acartia tonsa, while in the outermost stations Temora turbinata and the polychaete larvae Loimia sp. dominated. The results demonstrate how variable the estuarine plankton horizontal structure can be over short time-scales even in mixed estuarine systems under relatively homogeneous conditions, highlighting the importance to consider such temporal scales for a more accurate understanding of the dynamics of these communities.

Abstract Foraminifera are diversified protists with high ecological and bioindicator importance. Physical-chemical parameters of the environment can be evaluated through the taphonomic analysis of the test coloring, because once they settle in the sediment their tests begin to behave as sedimentary particles. Five urbanized tropical Brazilian beaches were sampled in this study in order to characterize the diversity, abundance, taxonomic and taphonomic structure of Foraminifera assemblages. General environmental characterization such as granulometric analysis, temperature and salinity was also performed. A total of 69 foraminiferan species were found, dominated by Quinqueloculina lamarckiana, Archaias angulatus, Amphistegina lessonii, Ammonia tepida and Eponides repandus. A large predominance of dead tests (>90%) was found, and only them were considered in further analyses. The cluster based on the taxonomic composition formed two groups, separating Miramar from the other beaches. Miramar was dominated by Ammonia tepida (18.9%), Sorites marginalis (16.8%), Quinqueloculina lamarckiana (13.9%) and Textularia agglutinans (10.2%), and had the highest density, number of species and diversity, what may be related with the sheltered nature of this beach and the dominance of fine sand. The other four beaches have high oceanic influence and the medium and coarse sand predominated. In these beaches Quinqueloculina lamarckiana dominated, representing between 30.9 and 38.7% of total foraminiferans. The taphonomic analysis indicates that Miramar presents a high deposition of tests and a low hydrodynamic energy, since the majority of tests were white. In Bessa, Manaíra and Seixas most of the tests were brownish, which is characteristic of beaches with high hydrodynamic energy, which causes the tests to be constantly brought to the oxidation zone.

ABSTRACT A new species of orbiniid, Scoloplos maranhensis sp. nov., is described from a tropical mangrove (Quebra Pote, state of Maranhão, Brazil, 02°41.344’S; 44°12.604’W) along with a comparative table with all Scoloplos species. The main distinguishing characters of S. maranhensis sp. nov. are thorax with 12 chaetigers, neuropodia from first chaetiger, notopodia and neuropodia without papillae, conical branchiae from 12th chaetiger to the end of the body, being larger and more robust in the anterior segments. Thoracic notopodia with seven crenulated capillary chaetae and abdominal notopodia with furcated and capillary chaetae. Thoracic neuropodia rounded with two crenulated capillary chaetae and six slender-smooth hooks, abdominal neuropodia with a post-chaetal lobe and only capillary chaetae. Papillae absent from posterior parapodia; one pair of cirriform anal cirri.

ABSTRACT The family Cossuridae is monogeneric for Cossura Webster & Benedict, 1887 which currently has 28 known species, three of which already recorded for Brazilian coast. In the present study we describe Cossura yacy sp. nov. increasing to 29 the number of known Cossuridae species. We have found and analyzed 60 individuals of C. yacy sp. nov. from São Marcos estuarine complex (ca. 02°S; 44°W) around São Luís Harbor (Maranhão, Brazil). It differs from other species of genus also by the presence of the two pairs of nuchal organs at lateral margins of the peristomium, branchial filament in the median region of the third chaetiger and by short and long capillary smooth chaetae with spinulosa on the distal half. These two chaetal types are present through the body both in the neuropodia and in the notopodia. Adults specimens of the Cossura yacy sp. nov. have seven notopodial and five neuropodial chaetae in the 5th parapodium; nine notopodial and seven neuropodial chaetae in the 20th parapodium; five notopodial and six neuropodial chaetae in the 43th parapodium. Pygidium has three long anal cirri, reaching the fourth posterior segment.

Abstract Specimens of Pegantha laevis H.B. Bigelow, 1909 and Pegantha triloba Haeckel, 1879 were found in oceanic waters off the northern Brazilian coast. The former species is clearly distinct due to the thickness and shape of peripheral channels, while the latter is recognized mainly due to the exumbrellar furrows and long otoporpae. This study represents the first actual record of P. laevis inside the Brazilian Economic Exclusive zone, since previous reports were far away from the coast, and clarifies the presence of P. triloba off Brazil.

Seasonal variation of large medusae abundance and biomass was studied in the North Bay, Santa Catarina, southern Brazil (27°30'S, 48° 32'W), from February to December 2005. Collecting was conducted seasonally with the help of fishing bottom trawl in 30-minute sections (12 in summer, 18 in each of the remaining seasons) in six stations, totaling 66 samples. Eight species were found: the hydrozoans Aequorea sp., Olindias sambaquiensis Müller, 1861, and Rhacostoma atlantica L. Agassiz, 1850; the cubozoans Chiropsalmus quadrumanus (Müller, 1859) and Tamoya haplonema Müller, 1859, and the scyphozoans Aurelia sp., Chrysaora lactea Eschscholtz, 1829 and Lychnorhiza lucerna Haeckel, 1880. Capture rates were low, up to 38 indiv. ha-1, and only ~47% of the samples were positive for jellyfish, comprising 206 individuals. Medusae abundance and species richness clearly changed from one season to another, but did not vary between the sites. Higher species richness (7 out of 8) and greater abundances were recorded during the fall (~60% and 72% of all medusae individuals and biomass respectively). Specific frequency of capture varied from 1.5 to 29% and C. lactea was the only species found in more than 25% of the samples. The three most common species dominated in different periods of the year: C. lactea during fall (78% of individuals and 60% of biomass), R. atlantica during winter (90% of individuals and 17% of biomass), and O. sambaquiensis in spring (78% of individuals and 40% of biomass). Only two individuals were caught during summer, one C. lactea and one R. atlantica. The results offer a general picture of the distribution of the macromedusae in the North Bay, but a continuous monitoring is desirable for a more detailed knowledge on the jellyfish dynamics in the Brazilian coastal waters.

A dieta das cubomedusas Tamoya haplonema Müller, 1859 (Carybdeidae) e Chiropsalmus quadrumanus (Müller, 1859) (Chirodropidae) foi analisada em espécimes coletados no litoral do Paraná (25º20' - 25º55'S; 48º10' - 48º35'W), sul do Brasil, entre dezembro de 1998 e dezembro de 2004, e é o primeiro estudo a abordar este aspecto da biologia de Cubozoa no Atlântico Sul. A cavidade gastrovascular da maioria (55%) dos 29 exemplares de T. haplonema mostrou-se vazia, e dos demais continha partes corporais de peixes teleósteos, como escamas, vértebras e otólitos. Em 726 exemplares de C. quadrumanus os itens alimentares mais importantes foram o camarão sergestídeo Peisos petrunkevitchi Burkenroad, 1945 e larvas de Brachyura, principalmente megalopas. Pequenos caranguejos, isópodes, peixes, ovos de peixes e nematóides foram menos comuns. Mudanças na dieta evidenciaram-se durante o crescimento de C. quadrumanus. Indivíduos menores alimentaram-se de maior variedade de presas, principalmente de larvas de Brachyura, e também apresentaram freqüência mais alta de estômagos vazios. À medida que cresciam, a ingestão de larvas diminuía de importância enquanto a do camarão P. petrunkevitchi aumentava, até este se tornar o principal item na dieta da espécie.

The diet of cubomedusae Tamoya haplonema Müller, 1859 (Carybdeidae) and Chiropsalmus quadrumanus (Müller, 1859) (Chirodropidae) was examined in specimens collected on the Southern Brazilian coast (25º20' - 25º55'S; 48º10' - 48º35'W), between December 1998 and December 2004. This is the first study to analyze this biological aspect in cubomedusae from the South Atlantic. The gastrovascular cavities of most (55%; n = 29) specimens of T. haplonema were empty while the remainder had teleosteans parts such as scales, vertebrae and otoliths. In C. quadrumanus (n = 726), the most important items were the pelagic sergestid shrimp Peisos petrunkevitchi Burkenroad, 1945 and Brachyura larvae, mainly megalops. Small crabs, isopods, fish, fish eggs and nematodes were less common. A dietary shift was clearly observed during C. quadrumanus growth. Smaller individuals consumed a greater variety of prey, mostly Brachyura larvae, and they also had higher frequencies of empty stomachs. As their size increased, megalopas decreased and P. petrunkevitchi became the most important item in their diet.

Olindias sambaquiensis Muller, 1861 (Olindiidae) é uma hidromedusa comum e abundante no litoral Sul do Brasil. Em contribuição ao estudo da espécie, variações morfológicas foram analisadas em 1092 exemplares coletados em águas costeiras de Guaratuba, Paraná. Em 70 (6,4%) indivíduos, foram reconhecidas alterações relacionadas ao número, forma e ramificações dos canais radiais e centrípetos, que resultaram, em diversos casos, em uma aparente mudança do padrão de simetria da espécie.

Olindias sambaquiensis Muller, 1861 (Olindiidae) is an abundant and common hydromedusae in the southern Brazilian littoral region. Morphology of 1092 specimens collected in coastal waters at Guaratuba, in Paraná, southern Brazil, was studied. The form, number and branching of the radial and centripetal canals were variable in only 70 individuals (6.4%), which, in some cases, were associated with apparent changes in symmetry pattern.

A cifomedusa Phyllorhiza punctata von Lendenfeld, 1884 (Mastigiidae), conhecida somente de águas do Indo-Pacífico até a década de 1950, é encontrada atualmente em diversos locais longe de sua distribuição original, provavelmente devido a atividades humanas. No Brasil, foi encontrada primeiramente em 1955 nas costas sul e sudeste, de onde desapareceu, ao menos no estágio de medusa, no início dos anos 1960. Uma outra população de medusas apareceu na década de 1990 no litoral do Estado da Bahia e, desde o final de 2001, reapareceram no litoral dos Estados do Paraná e Santa Catarina (25º20'S, 48º12'W a 27º26'S, 48º22'W), onde têm ocorrido em grande abundância durante os meses de verão. Durante o outono, segue um declínio da população, até seu desaparecimento no inverno. As razões desse recente aparecimento da espécie no Brasil são desconhecidas, entretanto, apesar dos poucos e esparsos registros, sua distribuição provavelmente ampliou-se por toda a costa, ocorrendo desde o Ceará (3 º43'S, 38º28'W), na região nordeste, até Santa Catarina, no sul do país.

The scyphozoan Phyllorhiza punctata von Lendenfeld, 1884 (Mastigiidae), known only from Indo-Pacific waters prior to the 1950s, is today found far from its original distribution, probably due to human activities. First seen in 1955 in Brazilian waters, medusae were found in southern and southeastern coasts, disappearing (at least as a medusa) in the early 1960's. Another population was found in the late 1990's, in the state of Bahia, and again in late 2001, many sightings were reported along the coasts of Paraná and Santa Catarina (25º20'S, 48º12'W to 27º26'S, 48º22'W). A large summer bloom, followed by decline and disappearance in winter and spring, occurs every year since then. The reasons for this recent mass occurrence are unknown. Despite few scattered records of the species in Brazil, it is probably widespread, occurring from the coast of Ceará (3º43'S, 38º28'W), in the northeast, to Santa Catarina, in the south.