Two new species of scale-worms, Harmothoe ruthae sp. nov. (Polynoidae) and Pholoides sinepapillatus sp. nov. (Sigalionidae) are described. In addition, we expand the description of Harmothoe gilchristi and extend its distribution to the Southwest Atlantic. The three species were found among the species of corals Lophelia pertusa, Solenosmilia variabilis, Enallopsammia rostrata, Madrepora oculata and Errina sp., a total of 257 samples of these corals were taken between 570 m and 1040 m depth, at the North-East coast of Rio de Janeiro, Brazil.
The species of Glycerella share a prostomium with four rings bearing four distal appendages, and proboscis with rod-like aileron. They also have the first two parapodia uniramous, while the following are biramous, with dorsal and ventral cirri; the notopodia bear simple capillaries chaetae. The neuropodia are provided in the upper part with compound spinigerous chaetae while those in the lower part are falcigerous. Glycerella magellanica has been reported in the south-west Indian Ocean, south and north-west Pacific Ocean, and north and central Atlantic Ocean. Herein, the first record of this species is reported in the south-west Atlantic, specifically off the north-east coast of Rio de Janeiro, in the Campos Basin. A single specimen of this species was collected during the ECOPROF project coordinated by CENPES/PETROBRAS, although this species has been recorded elsewhere in muddy sediments. In this study the specimen was collected in a dead fragment of the coral Solenosmilia variabilis, at 745 m depth. Morphologically the specimen is very similar to that used in the original description. However, some morphological differences were found related to the appearance of the compound chaetae and aileron. These differences may indicate either that in the original description these features were overlooked, or rather a case of intra-specific variation.
The distribution of species depends on the relationship with other species and the influence of abiotic factors, modulated by long‐term evolutionary and biogeographic processes. Polychaetes and fish are important components of the biota that inhabit estuarine systems, coexisting in various habitats, although the relationship between these groups and their responses to environmental variables is poorly understood. This study aimed to assess the concordance between fish and polychaete communities in three zones (inner, middle, and outer) of a tropical bay and to determine environmental influences on these communities. The raised hypothesis is that benthic fish is associated with polychaetes and that these taxonomic groups respond differently to environmental conditions. Environmental characteristics were the main drivers determining the occurrence of fish species and polychaetes families; however, no consistent relationship was observed between fish and polychaetes. Sediment granulometry seems to be an essential driver in determining polychaetes and fish distribution while turbidity and phosphorus were also important for fish. The three zones differed in both water physicochemical and sediment (nutrients and granulometry) variables, which determined their uses by different fish and polychaetes species. Only one fish species, the gerreid Eucinostomus argenteus showed a weak but significant association with the Goniadidae and Spionidae polychaetes, which may be associated with similar environmental preferences of both taxa. The lack of a consistent relationship between benthic fish and their likely invertebrate prey may be associated with the small spatial scale of this study and the early fish life stages. Most fish in shallow coastal areas are still in their early life, feeding mainly on polychaetes and other benthic macroinvertebrates, and as the area is shallow, planktonic organisms may be included in their diet, thus relieving predation pressure on benthic organisms. These findings are important to unveil relationships among different taxonomical groups and their environment.
The genus Naineris differs from other genera of the Orbiniidae in that all its species possess a rounded prostomium and one or two achaetous rings. Currently, 21 species of this genus have been described worldwide, five of which are recorded from Brazil. Naineris aurantiaca is the only species originally described from the Brazilian coast and the original description is the only record of this species. The description is short and vague, making identification difficult. From recent samples obtained in the type locality of Florianópolis, Brazil, we were able to study specimens of Naineris aurantiaca and redescribe the species. Diagnostic characters for this species are the presence of pre- and post-branchial papillae, anterior branchiae in thoracic segments considerably smaller than those of the rest of the body, distinct dorsal sensory organ from chaetiger 12 onwards, the chaetal arrangement of the thoracic neuropodia (crenulated capillaries in a lower oblique row, uncini in an upper oblique row, subuluncini in two anterior transverse rows, and acicular spines in a posterior row), interramal papillae only present on abdominal parapodia, and the presence of furcate chaetae in the abdominal notopodia. Here, we designate a neotype for the species and discuss the morphological variations we observed among specimens.
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