Eupanthalis rudipalpa Amaral & Nonato, 1984 was described based on three incomplete, colorless specimens and has not been reported since its original description; the epithet rudipalpa means "hirsute palps", a characteristic that separates it from other congeneric species. Eupanthalis McIntosh, 1876 and Euarche Ehlers, 1887, and their respective type species, E. kinbergi McIntosh, 1876 and E. tubifex Ehlers, 1887, were considered synonyms (E. rudipalpa as a junior synonym of E. tubifex, a cosmopolitan species) by some authors, because both have sessile eyes and two or three antennae. Nonetheless, these two genera are, in fact, distinct. Their type species can clearly be separated using some prostomial features. We provide an emended diagnosis of Euarche, and re-instate E. rudipalpa, redescribing it based on a Brazilian specimen (original type specimens lost). Illustrations showing body pigmentation pattern and a key to all species of Eupanthalis are also provided.

We analyzed the composition and spatial distribution of macrobenthos in the Cachoeira River estuary, Ilhéus, Bahia, Brazil. Samples were taken bimonthly from July 2008 to May 2009 at six stations along the estuary. In total, 613 individuals belonging to 71 taxa were collected. Molluscs showed the highest richness and abundance, followed by polychaetes. The spatial distribution of macrobenthos was influenced by salinity and by sediment characteristics. In the outer area microgastropods, the bivalve Donax gemmula, and the polychaete Drilonereis sp., were conspicuous. In the river mouth, the carnivorous gastropods Olivella minuta and Anachis obesa and the algal grazers Neritina virginea and Littorina ziczac predominated. In the middle estuary, there was a predominance of the polychaete Hemipodia californiensis. The euryhaline bivalves Tellina sp., Anomalocardia brasiliana, and Tagelus plebeius and the deposit-feeding polychaetes Heteromastus filiformis and Capitella cf. capitata were predominant in the inner estuary. Salinity, sediment characteristics, and dietary habits were important in the composition and distribution of organisms in this estuary.

En este estudio se analizó la composición y la distribución espacial del macrobentos en el estuario del río Cachoeira, Ilhéus, Bahía, Brasil. Las muestras fueron recolectadas cada dos meses desde julio de 2008 a mayo de 2009 en seis estaciones de muestreo. En total, se recogieron 613 individuos pertenecientes a 71 taxa. Los gasterópodos mostraron la mayor riqueza y abundancia, seguidos por los poliquetos. La distribución del macrobentos fue influenciada por la salinidad y los parámetros de sedimentos. En la parte externa del estuario fueron abundantes los microgastrópodos, el bivalvo Donax gemmula y el poliqueto Drilonereis sp. En la desembocadura predominaron gasterópodos carnívoros Olivella minuta y Anachis obesa y pastoreadores Neritina virginea y Littorina ziczac. Predominaron en la zona intermedia el poliqueto Hemipodia californiensis y en el sector interno bivalvos eurihalinos Tellina sp., Anomalocardia brasiliana y Tagelus plebeius y los poliquetos depositívoros Heteromastus filiformes y Capitella cf. capitata. Características de salinidad, sedimentos, y hábitos alimentarios son importantes en la composición y distribución de los organismos en este estuario.

Se estudiaron las comunidades bénticas de anélidos durante un periodo de un año (de agosto/95 a julio/96) en dos sectores de las playas Engenho d’Água and São Francisco, Canal de São Sebastião, donde el sustrato está compuesto por una mezcla de arena y fragmentos de roca. Se usaron parámetros abióticos como salidad del agua intersticial y propiedades de sedimento para caracterizar el ambiente. Los poliquetos estuvieron bien representados en los dos sectores y su distribución fue relacionada con el tiempo de sedimento. La densidad de los individuos y el número de táxones fuero mayores en São Francisco, mientras que la diversidad y la equidad fueron mayores en Engenho d’Água. Esta diferencia puede ser una consecueciade u enriquecimiento orgánico causado por una entrada doméstica y la salinidad más baja y variable en São Francisco. Debido a estos factores, la alta densidad de especiesoprtunistas como Capitella capitata ssp., Scolelepis squamata, Laeonereis acuta y varios oligochaetes, representó 75.5% de la abundancia local en ese sector

Benthic annelid communities were studied during a one-year period (August/95 to July/96) in two sectors of the beaches Engenho d’Água and São Francisco, São Sebastião Channel (São Paulo, Brazil), where the substrate is composed by a mixture of sand and rock fragments. Abiotic parameters such as salinity of interstitial water and sediment properties were used to characterize the environment. The polychaetes were well represented in the two sectors and their distribution was related with sediment type. The density of individuals and the number of taxa was higher at São Francisco, while the diversity and the evenness were higher at Engenho d’Água. This difference can be a consequence of organic enrichment caused by domestic input, and of the lower and more variable salinity at São Francisco. Due to these factors, a high density of opportunistic species, like Capitella capitata ssp., Scolelepis squamata, Laeonereis acuta and several oligochaetes, represented 75.5% of total abundance at this sector