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Until now, four species of the genus Chondrochelia Gutu, 2016 have been recorded from America. Using morphological and molecular data, we were able to recognize and describe two new species, Chondrochelia caribensis sp. nov. from the Mexican Caribbean and Chondrochelia winfieldi sp. nov. from the Gulf of Mexico. We found significant genetic divergence values between species based on the nucleotide sequences of cytochrome oxidase subunit I to support the morphological data. Also, the range of distribution of two species: Chondrochelia mexicana (Jarquín-González, García-Madrigal & Carrera-Parra, 2015) and Chondrochelia ortizi (Jarquín-González, 2016), were expanded within their described geographic regions. In contrast, the supposed distribution of the Brazilian C. dubia in the Mexican Caribbean and the Gulf of Mexico was rejected. Additionally, Chondrochelia algicola (Harger, 1878) was redescribed based upon type material. Minute details and ornamentation of some structures of three species were examined using SEM.

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A new species of deep-water brachyuran crab, Euphrosynoplax dincao, from southeastern Brazil is described and illustrated. The genus Euphrosynoplax currently consists of two species, E. clausa Guinot, 1969, and E. campechiensis Vázquez-Bader & Gracia, 1991, both only known from the Gulf of Mexico. The new species can be easily separated from its northern counterparts by a suite of carapace and appendage characters. Euphrosynoplax campechiensis is recorded for the first time from the Caribbenan Sea (Guadeloupe and between Saint Kitts and Nevis).(AU)

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Although crustaceans are traditionally preserved in liquids (formaldehyde and/or ethyl alcohol), those substances tend to alter their morphological aspects. Glycerin, used in human anatomy, is considered a good substitute for formaldehyde, as it preserves animals in states similar to in vivo conditions. There are no records in the literature, however, concerning the use of glycerin for conserving invertebrates. The objective of this work was to elaborate and evaluate alternative techniques for conserving the crustacean Ucides cordatus (Linnaeus, 1763). Six fixatives (1, 3, 4 and 5% formaldehyde, 70% alcohol, and dietrich solution) and two controls (positive and negative) were tested, as well as the effects of freezing before fixation on the integrity of U. cordatus specimens. Our results were evaluated with respect to nine variables. The treatments that demonstrated the best aesthetic results were 4% formaldehyde and 70% ethyl alcohol. The freezing of the animals resulted in brittle organs in all treatments tested. The technique discussed here is extremely promising for the conservation of animals for educational purposes, as it produces preserved specimens that are aesthetically similar to their in vivo conditions.(AU)

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Although crustaceans are traditionally preserved in liquids (formaldehyde and/or ethyl alcohol), those substances tend to alter their morphological aspects. Glycerin, used in human anatomy, is considered a good substitute for formaldehyde, as it preserves animals in states similar to in vivo conditions. There are no records in the literature, however, concerning the use of glycerin for conserving invertebrates. The objective of this work was to elaborate and evaluate alternative techniques for conserving the crustacean Ucides cordatus (Linnaeus, 1763). Six fixatives (1, 3, 4 and 5% formaldehyde, 70% alcohol, and dietrich solution) and two controls (positive and negative) were tested, as well as the effects of freezing before fixation on the integrity of U. cordatus specimens. Our results were evaluated with respect to nine variables. The treatments that demonstrated the best aesthetic results were 4% formaldehyde and 70% ethyl alcohol. The freezing of the animals resulted in brittle organs in all treatments tested. The technique discussed here is extremely promising for the conservation of animals for educational purposes, as it produces preserved specimens that are aesthetically similar to their in vivo conditions.

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Spatial and temporal distribution of two species of adult´s ostracods (Cyprideis sp. and Cyprideis salebrosa) were studied as a function of the rainfall patterns in the Guanabara Bay, Rio de Janeiro, Brazil. Samples were taken in ten stations, along six surveys representing three periods (Dry, Early and Late Rainy) for two years. Stations were nested in four areas (Outer, Central, EPA Guapimirim and Impacted). The bottom water (temperature, salinity, dissolved oxygen and oxygen saturation) were measured in each area to characterize the influence of seasonal variations by rainfall. Cyprideis sp. and Cyprideis salebrosa showed patterns distribution to seasonality/surveys (p = 0,002 and p 0,001, respectly). The spatial distribution of Cyprideis sp was significantly different areas studied (p 0.001) indicated well defined areas and distribution in along of the surveys. However, C. salebrosa showed homogeneous distribution in along of the areas within of each survey (p 0.001). Redundancy Analysis (RDA) for the two years evidenced environment preference of the Cyprideis sp. for areas with marine conditions (high influence for channel central) and C. salebrosa for brackish water (high influence of the rivers). This observation reinforces of the existence of areas created by the seasonality of pluviometric regime, a possible dispersion of the adults ostracods and possibility the use with bioindicators.(AU)

A distribuição espacial e temporal de duas espécies de ostracodes adultos (Cyprideis sp. e Cyprideis salebrosa) foi estudada em função do padrão pluviométrico na Baía de Guanabara, Rio de Janeiro, Brasil. As amostras foram coletadas em dez estações ao longo de seis campanhas, representando três períodos (Seco, Pré e Pós Chuvoso) por dois anos. As estações foram agrupadas em quatro áreas (Externo, Central, EPA Guapimirim e Impactado). A água do fundo (temperatura, salinidade, oxigênio dissolvido e saturação de oxigênio) foi medida em cada área para caracterizar a influência das variações sazonais pela chuva. Cyprideis sp. e Cyprideis salebrosa mostrou distribuição de padrões para sazonalidade/campanhas (p = 0,002 e p 0,001, respctivamente). A distribuição espacial de Cyprideis sp. foi significativamente diferente das áreas estudadas (p 0,001) indicou áreas bem definidas e distribuição ao longo das campanhas. No entanto, C. salebrosa mostrou distribuição homogênea ao longo das áreas dentro de cada campanha (p 0,001). A Análise de Redundância (RDA) para os dois anos evidenciou a preferência ambiental dos Cyprideis sp. para áreas com condições marinhas (alta influência para o canal central) e C. salebrosa para águas salobras (alta influência dos rios). Essa observação reforça a existência de áreas criadas pela sazonalidade do regime pluviométrico, uma possível dispersão dos adultos de ostracodes e a possibilidade do uso como bioindicadores.(AU)

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Synopia ultramarina Dana, 1853 is considered a circumtropical species and was originally described based on material collected from two localities near halfway between the southwestern Africa and northeastern Brazil. The species is redescribed here with samples from Fernando de Noronha Archipelago, Pernambuco state, northeastern Brazil. The material examined was collected by SCUBA diving, from rhodolith beds, in Ressureta Channel, between Meio and Rata Islands. Additional material was collected from off Ceará state coast, during environmental consultancies, by Petrobras S. A., and off Pernambuco state coast, during the Project REVIZEE NE IV. Discussion on morphological variations of the species is presented, based on the studied material and previous descriptions in the literature.(AU)

Synopia ultramarina Dana, 1853 é considerada uma espécie circumtropical e foi originalmente descrita com material coletado em duas localidades, a meio caminho entre o sudoeste da África e o nordeste do Brasil. A espécie é redescrita aqui com amostras do Arquipélago de Fernando de Noronha, estado de Pernambuco, nordeste do Brasil. O material estudado foi coletado por mergulho autônomo, em camas de rodolitos, no canal Ressureta, entre as ilhas do Meio e Rata. Material adicional foi coletado ao largo da costa do estado do Ceará, durante consultorias ambientais coordenadas pela Petrobras S. A., e ao largo da costa do estado de Pernambuco, durante o Projeto REVIZEE NE IV. É apresentada discussão sobre as variações morfológicas da espécie, baseada no material estudado e em descrições prévias na literatura.(AU)

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Synopia ultramarina Dana, 1853 is considered a circumtropical species and was originally described based on material collected from two localities near halfway between the southwestern Africa and northeastern Brazil. The species is redescribed here with samples from Fernando de Noronha Archipelago, Pernambuco state, northeastern Brazil. The material examined was collected by SCUBA diving, from rhodolith beds, in Ressureta Channel, between Meio and Rata Islands. Additional material was collected from off Ceará state coast, during environmental consultancies, by Petrobras S. A., and off Pernambuco state coast, during the Project REVIZEE NE IV. Discussion on morphological variations of the species is presented, based on the studied material and previous descriptions in the literature.

Synopia ultramarina Dana, 1853 é considerada uma espécie circumtropical e foi originalmente descrita com material coletado em duas localidades, a meio caminho entre o sudoeste da África e o nordeste do Brasil. A espécie é redescrita aqui com amostras do Arquipélago de Fernando de Noronha, estado de Pernambuco, nordeste do Brasil. O material estudado foi coletado por mergulho autônomo, em camas de rodolitos, no canal Ressureta, entre as ilhas do Meio e Rata. Material adicional foi coletado ao largo da costa do estado do Ceará, durante consultorias ambientais coordenadas pela Petrobras S. A., e ao largo da costa do estado de Pernambuco, durante o Projeto REVIZEE NE IV. É apresentada discussão sobre as variações morfológicas da espécie, baseada no material estudado e em descrições prévias na literatura.

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Mesozoic rocks with exceptional preservation of marine arthropods are known worldwide but largely restricted to mid-high latitudes. The scarcity of assemblages with exceptional preservation in low, tropical latitudes greatly limits our understanding of the origins of several modern groups and the evolution of tropical biotas through time. Here, we report the oldest crown Cumacea, or 'comma' shrimp (Arthropoda: Eumalacostraca: Peracarida) with modern familial affinities, from a new mid-Cretaceous (95-90 Ma) Lagerstätte in tropical South America. Cumaceans have one of the poorest fossil records among marine arthropods, despite today being abundant and speciose benthic organisms associated with fine-grained sediments with high fossilization potential. Eobodotria muisca gen. et sp. nov., found in mass accumulation surfaces, preserves with detail the gut, mouth parts, thoracic legs/pereopods, pleopods, uropods bearing setae, antennal flagella and even small eyes bearing ommatidia. These features, rarely preserved in fossil crustaceans, plus the large sample size (greater than 200 individuals, 6-8 mm long), allow us to discuss phylogenetic/systematic aspects and explore possible mechanisms behind their unusual accumulation. Eobodotria bridges an approximately 165 Myr gap in the cumacean fossil record, provides a reliable calibration point for phylogenetic studies and expands our understanding of exceptional preservation in past and present tropical settings.

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Cladogenesis is often driven by the interplay of dispersal and vicariance. The importance of long-distance dispersal in biogeography and speciation is increasingly recognised, but still ill-understood. Here, we study faunal interconnectivity between four large Brazilian floodplains, namely the Amazon, Araguaia, Pantanal (on Paraguay River) and Upper Paraná River floodplains, investigating a species complex of the non-marine ostracod genus Strandesia. We use DNA sequence data from the mitochondrial COI and the nuclear Elongation Factor 1 alpha genes to construct molecular phylogenies and minimum spanning networks, to identify genetic species, analyse biogeographic histories and provide preliminary age estimates of this species complex. The Strandesia species complex includes five morphological and eleven genetic species, which doubles the known diversity in this lineage. The evolutionary history of this species complex appears to comprise sequences of dispersal and vicariance events. Faunal and genetic patterns of connectivity between floodplains in some genetic species are mirrored in modern hydrological connections. This could explain why we find evidence for (aquatic) long-distance dispersal between floodplains, thousands of kilometres apart. Our phylogenetic reconstructions seem to mostly indicate recent dispersal and vicariance events, but the evolution of the present Strandesia species complex could span up to 25 Myr, which by far exceeds the age of the floodplains and the rivers in their current forms.

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Abstract This study presents a review of scientiometric data about freshwater microcrustaceans (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca, Notostraca and Conchostraca) in Brazil from 1990-2014. This review is based on 179 papers published across four databases, using the following keywords in the search: microcrustaceans, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, zooplankton, reservoir, river, ponds, reservoirs, wetlands, caves, lakes, limnology, ecology, aquatic, taxonomy, systematics, morphology and biogeography. No studies were identified that addressed freshwater microcrustaceans in four (Amapá, Roraima, Alagoas and Espírito Santo) of the 27 Brazilian Federative States. Forty-five percent of the included studies were concentrated within three of the most populous states (São Paulo, Minas Gerais and Paraná), which also have a long tradition of limnological study. The included studies mostly addressed reservoirs for hydropower generation (22%), multiple environments (22%), rivers (14%) and small artificial reservoirs (11%). Pools, ponds, small lakes, wetlands and phytothelma were not widely studied. Cladocera (48%) and Copepoda (48%) were the most studied groups. No studies were identified that addressed Notostraca, Anostraca or Conchostraca. The sharp increase in the number of published freshwater studies after 2000 is likely a result of increased internet facilities and the implementation of the Scielo platform. Ecology was most frequently the study focus (~50%), followed by taxonomy. Three journals (two Brazilian and one international) accounted for the publication of 44% of the Brazilian studies on microcrustaceans. We expect the frequency of studies employing newer technologies to increase in the coming years. Based on our findings, we propose that future studies should focus on the least well-studied states and should integrate biogeography and systematic approaches. Further data on the fauna within environmental sub-types in Brazil is required.

Resumo Esse estudo apresenta uma revisão cienciométrica para trabalhos com microcrustáceos de água doce (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca Notostraca e Conchostraca) no Brasil entre 1990-2014. Essa revisão foi baseada em 179 artigos científicos encontrados em quatro bases de dados, usando as seguintes palavras-chave: Microcrustáceos, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Chydoridae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, Zooplankton, reservatório, rio, lagoas, áreas inundáveis, cavernas, lagos, limnologia, ecologia, aquático, taxonomia, sistemática, morfologia e biogeografia. Não foram encontrados estudos para microcrustáceos de água doce em quatro (Amapá, Roraima, Alagoas e Espírito Santo) dos 27 Estados da Federação Brasileira. Quarenta e cinco por cento dos estudos foram concentrados em três dos estados mais populosos (São Paulo, Minas Gerais e Paraná), os quais têm longa tradição em estudos limnológicos. A maioria dos estudos analisou reservatórios de hidrelétricas (22%), ambientes múltiplos (22%), rios (14%) e pequenos reservatórios artificiais (11%). Ambientes tais como, pequenos lagos, poças, lagoas, brejos e fitotelmatas não foram muito estudados. Cladocera (48%) e Copepoda (48%) foram os grupos mais estudados. Não foram encontrados trabalhos que analisaram Notostraca, Anostraca ou Conchostraca. O salto no número de estudos publicados depois do ano 2000 parece ser resultado do aumento das facilidades da internet e criação da plataforma Scielo. Ecologia foi a área mais focada nos estudos (~50%), seguida pela taxonomia. Três revistas (duas brasileiras e uma internacional) contêm 44% dos artigos publicados sobre microcrustáceos no Brasil. Espera-se que a frequência de estudos utilizando novas tecnologias aumente nos próximos anos. Baseado nos nossos resultados, propõe-se que trabalhos futuros devam focar os estados menos estudados e integrem abordagens biogeográficas e sistemáticas. Mais dados sobre a fauna de microcrustáceos dentro dos tipos de ambiente menos estudados no Brasil também são necessários.

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This study presents a review of scientiometric data about freshwater microcrustaceans (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca, Notostraca and Conchostraca) in Brazil from 1990-2014. This review is based on 179 papers published across four databases, using the following keywords in the search: microcrustaceans, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, zooplankton, reservoir, river, ponds, reservoirs, wetlands, caves, lakes, limnology, ecology, aquatic, taxonomy, systematics, morphology and biogeography. No studies were identified that addressed freshwater microcrustaceans in four (Amapá, Roraima, Alagoas and Espírito Santo) of the 27 Brazilian Federative States. Forty-five percent of the included studies were concentrated within three of the most populous states (São Paulo, Minas Gerais and Paraná), which also have a long tradition of limnological study. The included studies mostly addressed reservoirs for hydropower generation (22%), multiple environments (22%), rivers (14%) and small artificial reservoirs (11%). Pools, ponds, small lakes, wetlands and phytothelma were not widely studied. Cladocera (48%) and Copepoda (48%) were the most studied groups. No studies were identified that addressed Notostraca, Anostraca or Conchostraca. The sharp increase in the number of published freshwater studies after 2000 is likely a result of increased internet facilities and the implementation of the Scielo platform. Ecology was most frequently the study focus (~50%), followed by taxonomy. Three journals (two Brazilian and one international) accounted for the publication of 44% of the Brazilian studies on microcrustaceans. We expect the frequency of studies employing newer technologies to increase in the coming years. Based on our findings, we propose that future studies should focus on the least well-studied states and should integrate biogeography and systematic approaches. Further data on the fauna within environmental sub-types in Brazil is required.

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The cumacean fauna of the Caribbean mesophotic reefs is remarkably rich but understudied. Herein, we present the description of 22 new species of the family Nannastacidae, including one from shallow reefs, 20 of them belonging to Cumella (Cumella) and two new species belonging to the subgenus Cumewingia. We have also included range extensions and new locations for ten previously known species of Cumella, two species in the genus Vaunthompsonia (family Bodotriidae) and one species in the genus Cubanocuma (family Nannastacidae). Taxonomic keys are provided for the western tropical Atlantic species of Cumella (Cumella) and Cumella (Cumewingia), separately for the adult males and females. Large sampling efforts and careful systematic studies, even in relatively well-characterized regions such as the Caribbean, can yield a surprising number of new discoveries. Our current findings emphasize our previous assertion that the mesophotic reefs are treasure troves of undiscovered benthic fauna and might be qualified as biodiversity hotspots.

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Bulbocythere calida gen. et sp. nov., a benthic marine ostracode, is herein described and illustrated. The geographic and bathymetric distributions of this new taxon are based on the analysis of 923 bottom samples collected along the entire Brazilian continental shelf in a depth range of about 11 to 280 m, plus sediments of 176 samples from the Sepetiba Bay and 37 samples from the Tamandaré Bay. In the study material, this ostracode was rare, and restricted to the warm waters of the E and NE shelves and to the substrates around the reefs of the Tamandaré Bay.

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Geometric morphometrics offer effective methods to obtain information about shape and shape variability. In ostracodology, landmark-based methods are, however, not well established. To test the applicability of geometric morphometric analyses for ostracods, we investigated shape variation among recent and fossil populations of the genus Cytheridella using a combination of landmarks and semilandmarks. The study focuses on the species' intraspecific morphological variability on a supra-regional scale, comparing living populations from Florida, Yucatán, Colombia and Brazil. We performed Generalized least-squares Procrustes Analysis on 508 adult and juvenile specimens (valves) including stages A-1 to A-4. The analyses show that the primary pattern in shape variation is ontogenetic allometry, supporting a clear separation of adults and juveniles. Shape changes are relatively small during ontogeny from A-4 to A-1. Greatest modification of valve shape occurs during the last molt phase. Insufficient differentiation of sexes is caused by females with less developed brood pouches. Disentangling size- and non-size-dependent shape changes reveals regional differences between populations of the species C. ilosvayi and supports its taxonomic distinction from a fossil relative (C. danielopoli). The distribution of regional morphotypes of C. ilosvayi in Florida, Mexico, and Brazil are congruent with fly ways of water birds.

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A new spinicaudatan species, Eulimnadia pampa sp. nov., is described from Argentina mostly based on the differential egg morphology. This species was collected from rainwater pools from Buenos Aires City and the provinces of Buenos Aires and Entre Ríos, and compared to other Neotropical species. Previous Argentine record of E. brasiliensis is shown to belong to our new species, which represents the southernmost Neotropical Eulimnadia. We also present new records of the Paraguayan Eulimnadia ovisimilis Martin and Belk, 1989 from northeastern Argentina. Eulimnadia santiaguensis is treated as a species inquirenda, thus we recognize only three Eulimnadia species in Argentina: E. pampa sp. nov., E. ovilunata and E. ovisimilis, and we provide a brief indentification key. We present the first description and SEM images of the putative Eulimnadia spermatophore, which we found in the new species.

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One new genus is erected and four new species of paratanaoidean tanaidaceans are described from deep waters in the northeastern Gulf of Mexico: one in each of the genera Collettea, Tanaella, and Pseudomacrinella, and one as a new genus in the family Anarthruridae. Keys to species in the genera Collettea, Tanaella, and the genera of the Anarthruridae are provided.

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Sixty-five ostracode species belonging to 41 genera and 17 families were recorded in the outer shelf and upper slope off Rio Grande do Sul and Santa Catarina states, southernmost Brazil, between 100 and 586 m water depth interval. The ostracode occurrences are hypothesized to be influenced by both, the coastal waters and the Antarctic Intermediate Water (AAIW). The taxonomy of some species of Bradleya Hornibrook, 1952, Legitimocythere Coles & Whatley, 1989 and Henryhowella Puri, 1957 previously described in the same study area is revised. Bradleya gaucha sp. nov., Legitimocythere megapotamica sp. nov., Apatihowella acelos sp. nov., Apatihowella capitulum sp. nov., Apatihowella besnardi sp. nov., Apatihowella convexa sp. nov., and Aversovalva tomcronini sp. nov. are herein proposed. Trachyleberis aorata Bergue & Coimbra, 2008 is reassigned to the genus Legitimocythere and Bradleya pseudonormani Ramos et al., 2009 has its diagnosis emended. Bythocypris praerenis Brandão, 2008 is considered a junior synonym of Bythocypris kyamos Whatley et al., 1998a. Apatihowella Jellinek & Swanson, 2003 and Legitimocythere species have well-defined bathymetric distributions and are potential paleoceanographic markers for the Quaternary in the Southern Brazilian Margin.

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Se analizó la estructura del hábitat, el crecimiento relativo, la heteroquelia, la estructura poblacional, la madurez morfométrica y la fecundidad de Pachycheles laevidactylus Ortmann, 1892, durante Abril, Mayo y Junio del 2005, en sustratos naturales de Mar del Plata, Argentina (38°02'S, 57°31'W). La cobertura algal, la exposición al oleaje y el tiempo de inmersión varió de manera significativa entre estratos y entre meses. La morfometría de las quelas no manifestó diferencias entre sexos. Las hembras mostraron el abdomen más grande que los machos. Si bien existió la heteroquelia, no se detectó lateralidad. Las tallas (ancho de caparazón) estuvieron comprendidas entre 0.67 mm a 9.3 mm para los machos, y entre 1.07 mm a 10.65 mm, para las hembras. La densidad de organismos varió entre meses y entre los estratos. La estructura poblacional, para el periodo de estudio, se explicó en función de la estructura del hábitat. La madurez morfométrica de las hembras fue registrada a los 4.38 mm de ancho de caparazón. El número de huevos se correlacionó positivamente con la talla de las hembras ovígeras con un mínimo de 2 huevos y un máximo de 160, pero esa relación dependió del avance en el desarrollo de los embriones.(AU)

Habitat structure, relative growth, the heterochely, population structure, morphometric maturity and fecundity of Pachycheles laevidactylus Ortmann, 1892 were analyzed during April, May and June 2005, in natural substrates of Mar del Plata, Argentina (38°02'S, 57°31'W). Algal cover, wave exposure and immersion time varied significantly between strata and between months. Chelae morphometry showed no differences between sexes. Females showed the greatest abdomen. While there was the heteroquelia, laterality not detected. The size (carapace width) ranged from 0.67 mm to 9.3 mm for males and from 1.07 mm to 10.65 mm, for females. The density of organisms varied among months and between strata. The population structure for the period of study explained depended on habitat structure. The morphometric maturity of females was recorded at the 4.38 mm of carapace width. The number of eggs was positively correlated with the size of the gravid females with a minimum of 2 eggs and a maximum of 160, but that relationship depended on progress in the development of embryos.(AU)

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Se analizó la estructura del hábitat, el crecimiento relativo, la heteroquelia, la estructura poblacional, la madurez morfométrica y la fecundidad de Pachycheles laevidactylus Ortmann, 1892, durante Abril, Mayo y Junio del 2005, en sustratos naturales de Mar del Plata, Argentina (38°02'S, 57°31'W). La cobertura algal, la exposición al oleaje y el tiempo de inmersión varió de manera significativa entre estratos y entre meses. La morfometría de las quelas no manifestó diferencias entre sexos. Las hembras mostraron el abdomen más grande que los machos. Si bien existió la heteroquelia, no se detectó lateralidad. Las tallas (ancho de caparazón) estuvieron comprendidas entre 0.67 mm a 9.3 mm para los machos, y entre 1.07 mm a 10.65 mm, para las hembras. La densidad de organismos varió entre meses y entre los estratos. La estructura poblacional, para el periodo de estudio, se explicó en función de la estructura del hábitat. La madurez morfométrica de las hembras fue registrada a los 4.38 mm de ancho de caparazón. El número de huevos se correlacionó positivamente con la talla de las hembras ovígeras con un mínimo de 2 huevos y un máximo de 160, pero esa relación dependió del avance en el desarrollo de los embriones.

Habitat structure, relative growth, the heterochely, population structure, morphometric maturity and fecundity of Pachycheles laevidactylus Ortmann, 1892 were analyzed during April, May and June 2005, in natural substrates of Mar del Plata, Argentina (38°02'S, 57°31'W). Algal cover, wave exposure and immersion time varied significantly between strata and between months. Chelae morphometry showed no differences between sexes. Females showed the greatest abdomen. While there was the heteroquelia, laterality not detected. The size (carapace width) ranged from 0.67 mm to 9.3 mm for males and from 1.07 mm to 10.65 mm, for females. The density of organisms varied among months and between strata. The population structure for the period of study explained depended on habitat structure. The morphometric maturity of females was recorded at the 4.38 mm of carapace width. The number of eggs was positively correlated with the size of the gravid females with a minimum of 2 eggs and a maximum of 160, but that relationship depended on progress in the development of embryos.

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Fennerosquilla is a monotypic genus that belongs to the family Squillidae, which has the highest generic diversity within Stomatopoda. This genus has been recorded in the north Atlantic Ocean, the Gulf of Mexico and Caribbean Sea, between 105 and 458 m depth. The present specimen was collected during the project "Avaliação da Biota Bentônica e Planctônica na porção offshore das Bacias Potiguar e Ceará", in 2011, from the continental slope region of Brazil. In this expedition Fennerosquilla heptacantha was found at 178-193 m depth, and represents the first record of the species in the south Atlantic Ocean (Rio Grande do Norte State, northeastern Brazil), expanding the southern limit distribution. The specimen is the largest recorded, measuring 149 mm total length. The pigmentation zone on median region of telson and all diagnostic characters are still preserved and agree with the original description. Fennerosquilla heptacantha has a disjunct deep water distribution (more than 100 m) in the tropical western Atlantic, mostly along the continental slope.

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