Abstract The Antarctic environment has special characteristics that influence the local marine life. The benthic organisms, adapted to these extreme conditions of life, are subject nowadays to effects of climate change. Recently, the consequences of glacier retreat on these assemblages have been observed in many West Antarctic Peninsula (WAP) regions, including King George Island (KGI). This study described the spatial variation of the benthic macrofauna in different areas of the Martel Inlet (Admiralty Bay - KGI), at depths around 25-30 m. Sampling was done in January 2001 at ten stations classified in localities according to their proximity to ice-margin/coastline in marine-terminating glacier (MTG), terrestrial-terminating glacier (TTG) and ice-free area (IFA). The total density and the abundance of annelids, nematodes, peracarid crustaceans and bivalves were higher at IFA stations. The locality discrimination by taxa and species was independent of available environmental/sedimentary conditions or was the result of unmeasured variables or species life history processes not assessed herein. Considering that our findings were obtained 21 years ago, they will be especially useful for comparing future studies of benthic assemblage responses to the influence of climate change and continuous glacier retreats in the WAP region.

ABSTRACT Agromyzidae (Insecta: Diptera) is a cosmopolitan family of acalyptrate flies, with almost 3,000 species worldwide distributed. Most species are leaf miners on a large number of plants. Among them, Liriomyza Mik, 1894 is a large genus of leaf-miner species that can cause significant damage to economically important crops and is considered agricultural pests, such as Liriomyza sativae Blanchard, 1938 and Liriomyza huidobrensis (Blanchard, 1926), which are herein investigated. The present study deals with the impact of climatic factors (temperature, humidity, and precipitation), seasonality, and parasitoid abundance on leaf-miner infestation during one year in five cultivated crops in Northeastern Brazil. Climatic factors for instance had different effects on L. sativae populations in melon and watermelon crops. Larval abundances were greater during the dry season for both species, L. sativae and L. huidobrensis, and abundance of adult parasitoids followed the increase of mining larvae.

Características morfológicas de quatro espécies de Scolelepis De Blainville, 1828 foram analisadas utilizando-se análise morfométrica com o ojetivo foi avaliar se essas espécies podem ser discriminadas através da utilização de dados morfométricos. Além disso, foram fornecidos novos caracteres que possam ser utilizados para uma reavaliação da taxonomia do gênero. A análise baseada nas variáveis canônicas revelou que S. chilensis, S. goodbodyi e S. squamata são mais similares entre si, quanto a forma, do que com S. acuta. Os caracteres mais significativos para a discriminação das quatro espécies foram o comprimento da brânquia, o comprimento da base do palpo até o vigésimo setígero, o comprimento e a largura do prostômio e a largura e o comprimento do setígero 5 e 20. Destes, destacam-se o formato das brânquias e do prostômio, pois vem sendo utilizados como caracteres diagnósticos em estudos taxonômicos do gênero.

Morphological characteristics of four species of Scolelepis De Blainville, 1828 were analyzed using morphometric analysis in order to evaluate whether these species can be discriminated using morphometric data. Furthermore, new informative characters that can be used for a reassessment of the taxonomy of the genus were also provided. The analysis based on canonical variables applied to the species revealed that S. chilensis, S. goodbody and S. squamata are more similar in shape to each other than with S. acuta. The most significant characters for discriminating the four species were gill length, length of the palp from the base until the twentieth chaetiger, length and width of prostomium and width and length of chaetigers 5 and 20. Of these, we highlight the shape of the gills and prostomium since they have been used as diagnostic characters in several taxonomic studies of the genus.

Populations of Ocyurus chrysurus were compared genetically and morphometrically along the West Atlantic coast to test the null hypothesis of population homogeneity in the area. Brazilian populations were found to be differentiated in shape (canonical variates analysis; F[48,515] = 10.84, p < 0.0001). Analyses of mitochondrial DNA sequences (663 bp of the control region) did not show any differences between Brazilian populations but could detect differences between Brazilian and Caribbean (Belize) populations. The samples from Pernambuco differed significantly from the other Brazilian populations in allozyme frequencies (11 loci; F ST = 0.167; p < 0.05), but this may have resulted from the small number of samples analysed for that population. Sequence variation of Belize samples departed from neutral expectations (Fu's FS = -8.88; p < 0.001). A mismatch distribution analysis points to an ancient population expansion in that area. We conclude that the genetic data do not allow the rejection of the null hypothesis of panmixia for Brazilian yellowtail snapper populations which should be treated as a single genetic stock, with a latitudinal gradient on their morphology which probably results from phenotypic plasticity. On the other hand, there is a severe restriction to gene flow between O. chrysurus populations from the Caribbean and from the southwestern Atlantic.

Estudos morfológicos em Eunice são muito comuns, especialmente em um contexto taxonômico e de relações evolutivas de táxons deste gênero. Neste estudo, optamos por uma abordagem morfométrica comparando cinco espécies de Eunice para avaliar a possibilidade de delimitá-las através de variáveis de forma. A morfologia de E.fucata, E.insularis, E. cf. ornata, E.rubra e Eunice sp. foi comparada utilizando-se análises de morfometria tradicional de 16 variáveis mensuradas. Após a remover o efeito de tamanho, uma Análise de Variáveis Canônicas aplicada às variáveis morfométricas permitiu a discriminação de todas as espécies. Em CV1, dois grupos maiores de espécies foram discriminadas: E.fucata/E.insularis e E. cf. ornata/E.rubra/Eunice sp. CV2 discriminou fortemente todas as espécies com E. cf. ornataapresentando escores maiores e E.rubra os menores. Os caracteres que diferenciaram as espécies foram o tamanho relativo das antenas, do peristômio e dos setígeros anteriores. Este estudo também demonstrou que a largura do peristômio e o comprimento dos palpos são as melhores variáveis para estimar o tamanho do corpo em Eunice, já que ambas estiveram altamente correlacionadas com o estimador de tamanho. Através de análises morfométricas foi possível delimitar as espécies e escolher caracteres diagnósticos para o gênero Eunice, um resultado provavelmente válido para outras espécies de poliquetas.

Morphology has been the subject of several studies in Eunice specially in the context of the taxonomy and evolutionary relationships of taxa within this genus. In this study we opt for a morphometric approach comparing five species of Eunice to assess if it was possible to delimitate them by shape variables. The morphology of E.fucata, E.insularis, E. cf. ornata, E.rubra, and Eunice sp. was compared using traditional morphometric analysis of 16 measured variables. After removing the size-effect, a Canonical Variates Analysis applied to morphometric variables was able to discriminate all species. In CV1 two major groups of species were discriminated: E.fucata/E.insularis and E. cf. ornata/E.rubra/Eunice sp. CV2 strongly discriminated all species, with E. cf. ornatawith higher scores and E.rubra with lower ones. The characters that differentiate the species were the relative size of antennae, peristomium and anteriormost setigers. This study also demonstrated that peristomium width and palps length were the best variables for body size estimation in Eunice, since they were highly correlated to the size-estimator. Through morphometric analysis it was possible to delimitate species and choose diagnostic characters for the genus Eunice, a result likely to be valid for other polychaete species.