Abstract in English:The Anostraca is a diversified crustacean group inhabiting essentially in temporary wetlands on all continents. The genus Dendrocephalus sensu stricto is endemic to tropical or subtropical Neotropical fresh water pools. Of the 13 described species, four are reported from Brazil. Species identification is based on morphological differences on the complex frontal appendage, the anterior thoracopods, and the gonopods. After a detailed comparison of the different Brazilian populations, we developed an illustrated identification key based on the variations of the frontal appendage. This key includes a new undescribed species recently found in Northern Minas Gerais. We present a simple tool to identify Brazilian Dendrocephalus species in order to encourage more studies on this generally neglected genus.
Abstract in English:A new species of the amphipod family Phoxocephalidae Sars, 1895, Pseudharpinia tupinamba sp. nov., is described from southeastern Brazilian continental shelf. The new species is closely related to the type-species of the genus, P. dentata Schellenberg, 1931 described from Magellan Province, and was misidentified as the latter species by some authors in the past. Pseudharpinia tupinamba sp. nov. differs from P. dentata by the number of articles in the accessory flagellum of antenna 1, ratio of length and width of the propodus of pereopod 6, size of the posteroventral lobe of the basis of pereopod 7, presence of slender setae in posterior margin of epimeral plate 3, presence of a corona of cuticular spines in dorsodistal margin of peduncle of uropod 2, ratio of length of the inner ramus and the first article of outer ramus of uropod 3, ratio of length and width of the telson, and presence of slender setae on the lateral margins of telson. The new described species is the unique of this genus known from the Brazilian continental shelf.
Abstract in English:The genus Hyalella Smith, 1874 is typical from the continental American waters and show high levels of endemicity. In Brazil, the occurrence of 12 species was reported, of which only Hyalella caeca Pereira 1989 is troglobiotic. A new species was found in a cave, Gruta da Toca, located near Itirapina city, state of São Paulo, Brazil. This species represents the second troglobiotic for the genus in Brazil.
Abstract in English:The South America Scleropactidae includes 53 nominal species distributed in 14 genera. In Brazil, there are 16 species recorded in the north and southeast regions. Here, two new species of Scleropactidae are described based on material collected in caves in the state of Pará, both troglobitic and allocated in the genus Circoniscus. Circoniscus buckupi sp. nov. can be distinguished from its congeners by the long second article of antennal flagellum, inner endite of maxillula with a small hook-like spine at the apex, a long dactylar organ with pectinate apex conferring a knife-shaped appearance and the absence of schisma in adults. Circoniscus carajasensis sp. nov. can be distinguished from Circoniscus buckupi sp. nov. by the presence of schisma on pereionite 1 in adults and dactylar organ with a fringe appearance.
Abstract in English:In an ecological context, information on the movement and activity is important for understanding the requirements of habitat, resource usage patterns and the potential of interspecific interactions. The aim of this study was to examine the displacement pattern on daily activity and occupancy of substrates by Aegla manuinflata using radio-telemetry technique on field on Southern Brazil. Four adult males were monitored during nine days. The aeglids showed a significantly greater displacement toward upstream than downstream. Aegla manuinflata individuals showed higher displacement activity during the night period. Although activity was not constant: the animals spent one or more days without displacement. All aeglids showed locomotion activity concentrated between 11:43 p.m. and 02:25 a.m., although it was not restrict to sunset period and night. Individuals showed specific occupation of different types of substrate, but a pattern in the occupation of substrates as a function of the photoperiod was not observed. In this study, using a new technique for tracking aeglids, it was concluded that A. manuinflata is capable of actively dislocate throughout the stream, either toward upstream and downstream, passing through obstacles which may represent ability of re-colonization. The animals are more active during the night period, probably a strategy to avoid predators that are active during the day; the selection of substrate is not associated to sediment texture.
Abstract in English:Trawling is known as one of less selective fishing gears and presents high index of accidental captures. The objective of this paper is to characterize the population structure, fecundity and relative growth of Leurocyclus tuberculosus often caught as bycatch in pink shrimp trawl. Sampling occurred between October 2008 and September 2009 in the coast of Rio de Janeiro State, using commercial shrimp trawl. The sample totalized 269 crabs, 168 males and 101 females (42 ovigerous). The sex ratio was 1:1.66 (M:F) and differed statistically from the expected (X²=16.68; p > 0.05). The carapace width (CW) ranged from 12.81 to 71.67 mm (mean ± SD: 48.77 ± 13.75 mm) and from 15.33 to 55.44 mm (36.19 ± 8.66 mm) in males and females, respectively. The size at onset of sexual maturity was estimated at 30 mm (females) and 55 mm (males). The individual fecundity ranged from 3,450 to 23,680 eggs/brood (10,327.3 ± 4,827.7). The analysis of relative growth did not differ from the Brachyura predictions. The histogram analysis showed that shrimp trawl affects the L. tuberculosus population equally, capturing from very young individuals to adults.
Abstract in English:The crabs of the genus Dissodactylus are well known as ectosymbionts of irregular echinoids belonging to Clypeasteroida and Spatangoida. Dissodactylus crinitichelis is the only species of the genus reported in Brazil. The pea crab species has been already recorded associated with four species of echinoids in Brazilian waters. This paper reviews the known hosts for D. crinitichelis and registers for the first time the association between the pea crab and the sand dollar Leodia sexiesperforata increasing to five the number of known hosts for the crab.
Abstract in English:Macrobrachium borellii is an abundant prawn of the Paraná River floodplain. Newly hatched juveniles have the general characteristics of adults, and they are proposed to have the same feeding habits. Its natural diet is composed mainly of animals' items rather than vegetals, of which dipteran larvae and oligochaetes are positively selected. However, the oscillations of the hydric cycle imply an adequacy of its selection according to prey availability in all seasons and moments of the ontogenetic development. This work verifies the predation behavior and the ontogenetic predation capacity of M. borellii feeding on three preys (cladoceran, dipteran larvae and oligochaetes) of different bioforms and mobility that represent its natural diet. The prawns were placed individually in containers where was offered one prey type in increasing amounts every 48 hours until any prawn ate the total amount offered. The predation behavior was recorded, and the amount consumed was verified after 24 hours. Both sizes of M. borellii were capable of preying on all food items used in this study. The search and catch was always made with the second queliped, suggesting a non-visual prey perception, and the handling was different for each prey. Cladoceran was the most consumed, followed by dipteran larvae and oligochaetes. The results show that, in both sizes, M. borellii has a trophic plasticity due to its capacity to prey on a variety of bioforms with differing mobility. This capacity could favor the ability of prawns to select the most profitable prey according to the changes in abiotic and ecological factors.
Abstract in English:In this paper, we describe and illustrate the morphology of the first larval stage of the prawn Macrobrachium brasiliense. Two ovigerous females were obtained in a stream environment, which belongs to Paraná River Basin, Southeastern of Brazil, and were maintained in laboratory until the time of hatching. The newly-hatched larva bears very advance morphological features, with benthic habits. They had sessile eyes and all appendages, except for the uropods; however, most of the appendages were not fully formed. The description given here is compared with the first larval stage of Macrobrachium species with abbreviated larval development from other localities.
Abstract in English:The alpheid shrimp Athanas dimorphus Ortmann, 1894, common and widespread throughout the Indo-West Pacific, is reported for the first time from Brazil, representing the first invasive alpheid species in Brazil, and the first species of the genus Athanas Leach, 1816 introduced to the western Atlantic. The present record is based on several specimens collected at two localities in Ceará, Pedra Rachada beach near the town of Paracuru, and Meireles beach in Fortaleza. Athanas dimorphus is very common at the second site, suggesting that a population of this species is now established in northwestern Brazil. An updated list of marine and freshwater decapods accidentally or voluntarily introduced to Brazil is provided.