Abstract in English:This paper concerns the chydorid cladoceran Leydigia (Neoleydigia) cf. striata Birabén, 1939 in plankton samples from Ciénaga El Convento, Colombia. The specimen from Colombia bears the diagnostic features of L (N) cf. striata as redescribed by Kotov and Elías-Gutiérrez (2003), Kotov et al. (2004), and Kotov, (2009). However, this particular specimen shows some subtle differences in the morphology of basal spine of claw, spine-like setules on first and second endopod segments of antenna II, and striation on valve. In the Neotropics, L. (N.) cf. striata Birabén, 1939 most closely resembles L. (N.) cf. ipojucae Brehm, 1938 in the structure of thoracic limb II and postabdominal claw, but can be separated from the latter by differences in setules in lateral fascicles on labrum, postpore distance (PP), shape of postabdomen, preanal margin of the postabdomen, and seta 2 of thoracic limb III.
Abstract in English:Three benthonic Harpacticoida (Crustacea) new to science were collected in the São Sebastião Channel region (SE Coast of Brazil): Rhizotrix virginiae n.sp. (Rhizotrichidae), Galapalaophonte alvaroi n. sp. (Laophontidae) and Laophontisochra terueae n.sp. (Nannopodidae). Though similar to described species from the NW Atlantic benthos, the Caribbean region and the Patagonian continental slope, they differ in details, such as number of leg segments and/or setae, ornaments, etc. and are here described for the first time.
Abstract in English:A new species of Cirolana is described from the Northeast Brazilian coast based on the material previously recorded as Cirolana palifrons and some other material misidentified as C. parva. The new species, C. lemoscastroi sp. nov., belongs to a group of species within the genus that have two dorsal longitudinal carinae on the pleotelson. A key to all Cirolana species recorded from Brazil is provided.
Abstract in English:The activity of the litter-feeding macrofauna affects litter decomposition rates at the local scale, and their preference for particular litter types is mediated by litter traits. Environmental changes such as invasion by exotic plants may change the characteristics of the litter at a local scale, with consequences to ecosystem processes. Here we evaluated the feeding preferences of four detritivores (terrestrial isopods) from two biogeographic regions (neotropical and palearctic), offering them native or non-native litter in cafeteria experiments. Our results show that isopods from different geographical regions exhibit essentially the same food preference, irrespective of whether or not they previously had encountered the litter tested. Combining the isopods' preference ranks with the principal component analysis of nine litter traits, we show that preference increases with increasing nitrogen and calcium contents and decreases with increasing toughness, C:N ratio and thickness, irrespective of the geographical origin of both litter and detritivores. We conclude that the palatability of a non-native litter to the native detritivore community can be predicted from their respective litter traits and thus, native detritivores will feed on a particular non-native litter type as likely as do detritivores in the native range of the plant. As the combination of traits that indicates palatability to the isopods also indicates litter decomposability, it could be possible to predict ecosystem responses in terms of litter decomposition rates upon changes in litter composition.
Abstract in English:This study was conducted in two estuarine inlets (Saco da Mangueira and Saco do Arraial) at the Patos Lagoon estuary, southern Brazil. The changes in relative abundance and size of post-larvae and juvenile shrimp Farfantepenaeus paulensis and juvenile blue crab Callinectes sapidus were compared, considering the influence of salinity and the presence of submerged seagrass meadows. The analyses were performed using generalized linear models (GLM) for abundance variations and ANOVA for variations on the size of individuals. The pink shrimp was more abundant at Saco da Mangueira, in seagrass meadows and areas of higher salinity. The blue crab was more abundant at Saco do Arraial and in lower levels of salinity. The importance of submerged vegetation for the blue crab lies in a preference of smaller crabs of the species for the seagrass meadows. It has been shown that these species choose different habitats in the estuary, and both the salinity and the presence of submerged seagrass meadows influence the selection of habitat.
Abstract in English:Differences on reproductive performance between two sampling points of the porcelain crab Pachycheles monilifer from Ubatuba (São Paulo, Brazil), one from Itaguá Beach (living on Schizoporella errata) and the other from Grande Beach (living on Phragmatopoma caudata) has been previously observed. Therefore could be expected a specific behavior in substrate preference to optimize the best biogenic habitat. Considering this premise, our goal was to test the substrate preference of this species when both substrates were simultaneously available. In total, 185 individuals were collected in these same localities and they were submitted to substrate selection experiments. The trials were conducted on containers with quiet seawater at 28 ± 1°C and under dark photoperiod. Specimens were exposed to substrates by 30 min. Trials started with the release of one animal per treatment in the middle of the opposite side to the substrate inside the containers. After the established time, the substrate preference of each porcelain crab was verified. As result, no preference pattern was found and the choices in the experiment were not significantly different from the expected. This lack of preferences may be an indication that porcelain crabs are generalists in habitat use regardless of sex of individuals and potential benefit in fitness. Therefore, the differences on the reproductive aspects of the P. monilifer probably are associated with environment factors not simulated in this study and may indicate the occurrence of plasticity in habitat selection behavior.
Abstract in English:Mud shrimps (formerly Thalassinidea) are common burrow dwelling decapod crustaceans in the littoral zone of the Persian Gulf and Gulf of Oman. Their burrow morphology was investigated using foam casting methods. The present study shows that the burrow morphology in Upogebia carinicauda is not consistent and the recorded variations are based on habitat type and some physical characteristics of sediments. Adult burrow morphology in sandy-muddy substrate with shells, and boulder field habitats were Y-shaped and complex burrows of horizontal channels with turning chambers and vertical connections to internal passages or crevices of boulders, respectively. In burrows of U. carinicauda, some narrow passages, connected to the upper part of adult burrows in sandy-muddy habitats, belong to juveniles. Another species, Neocallichirus jousseaumei was found under boulders in sandy-muddy habitats of the Gulf of Oman and Qeshm Island, Persian Gulf. Since this type of habitat is special in some features, no conspicuous ex-current openings (usually obvious as conical mounds of extruded sediment) have been observed on the sediment surface; as these were hidden among the boulders surrounded by mixed sand and shells. The only method for observing this type of burrow was to remove the boulders by hand or lever.
Abstract in English:Clam shrimps are small crustaceans typical of temporary ponds. To survive in these highly variable and unpredictable environments, they produce resistant eggs. These settle on the bottom of pools where they remain dormant, forming a cyst bank. We investigated the effects of light and temperature, both of which break the dormancy of Eulimnadia colombiensis eggs. Dormancy was not broken below 25°C, irrespective of the effect of light. Hatching was highest (27.8% of eggs) at 30°C in continuous light. Light also influenced the development of eggs, and some nauplii hatched spontaneously without drought stress. Methods are suggested for the cultivation of this species in tropical areas.
Abstract in English:Some members of the Pinnotheridae family exhibit close symbiotic relationships with bivalves, which may cause severe damage to the mollusk. The condition index (CI) is a tool that serves to evaluate the effect of biotic and abiotic factors on the morphology and physiology of mollusks, including those caused by symbiotic organisms. In the present study, we evaluated the effects of the infestation of the pinnotherid crab Austinotheres angelicus on the oyster Saccostrea palmula through monthly sampling (April to November 2012) in Punta Morales, Pacific coast of Costa Rica. A total of 245 oysters were analyzed, of which 38% were infested by the pinnotherid crab. Most of the oysters analyzed (92%) varied in depth between 1.5 and 15.0 mm; 89% of the infested oysters were in this depth range. The prevalence was positively correlated with the depth of the oyster. Our results revealed that crab infestation could reduce the CI by 11 to 33%. The obtained findings suggest that the infestation by A. angelicus provokes alterations of the flesh production of the oyster, especially when the association is with a pair of crabs including an ovigerous female. The association of A. angelicus with S. palmula is best described as facultative parasitism for male crabs and obligatory parasitism for females.