Mariana B. Lacerda

Sexual maturity and reproductive period of the swimming blue crab Callinectes danae Smith, 1869 (Brachyura: Portunidae) from Guaratuba Bay, Paraná State, southern Brazil

This work aims to estimate the average size at the onset of morphological and physiological sexual maturity and the reproductive period of Callinectes danae. Specimens were captured from a shrimp fishing boat equipped with a trawl net from March 2009 to February 2010. After sorting, crabs were sexed, and the following morphometric dimensions were measured: carapace width (CW), length and height of the major (MAP and HMAP), and the minor cheliped propodus (MIP and HMIP) for both sexes, and the abdominal width for females (AW). The onset of morphological maturity was estimated with the REGRANS program, in which the inflection point is calculated. The size at the onset of physiological maturity was determined by logistic regressions fitted to the relationships between the percentages of juvenile and adult individuals of each CW. A total of 893 individuals were sampled. Of these individuals, 389 were males, 472 non-ovigerous females, and 32 ovigerous females. The CW ranged from 19.81 to 117.17 mm for males, 19.91 to 113.11 mm for non-ovigerous females, and 70.55 to 88.60 mm for ovigerous females. Morphological sexual maturity was attained at 86.47 mm CW (males) and 67.87 mm CW (females). The size at the onset of physiological maturity was calculated to be 86.50 mm CW (males) and 67.00 mm CW (females). Due to the closeness of these values, both techniques were deemed suitable for determination of the onset of sexual maturity in C. danae. This species reproduces throughout the year, but reproduction is more intense during the winter. Mature males are present throughout the year. Data from this investigation will help resource managers to develop strategies that will ensure a sustainable harvest of this important species of swimming crab in southern Brazil.

Substrate selection of the caprellid Caprella dilatata (Crustacea, Amphipoda)

The diversity of space and the variability of environmental conditions that affect habitat quality for organisms, are determining factors in the selection of an ideal habitat. The present study aimed to understand the substrate selectivity of a caprellid amphipod, Caprella dilatata, in natural environments along the southern Brazilian coast and in laboratory conditions. A total of 31 biological substrates sheltering invertebrates were collected across various localities. C. dilatata was recorded in 11 substrate samples, and was a dominant species only in finely branched and softly surfaced algal substrate, ascidian and bryozoan colonies, and the surfaces of buoys and ropes. Laboratory experiments for substrate selection by C. dilatata were performed under two conditions: two-algal substrates and four-algal substrates. The phytals of Gracilaria cervicornis, Pterocladia capillacea, Sargassum cymosum and Ulva fasciata were selected for the experiments due to their contrasting degrees of ramification. In the first experiment (two-algal substrates), caprellids were transferred to three aquaria containing varied combinations of two algal substrates with a total of nine combinations. For the second experiment (four-algal substrates), all species of algae were combined together in each aquarium. Amphipods obtained for laboratory experiments always showed an exoskeleton color very close to that of the original algal substrate. Caprellids showed a strong preference for the original algal substrate. Despite the cosmopolitan morphology of C. dilatata for selection of the substrate, the individuals were mostly found in structurally complex substrates, and the experiments show the importance of camouflage for these caprellids.

Redescription of the rare amphipod crustacean Pseudaeginella montoucheti (Quitete, 1971) from Brazil

Abstract Pseudaeginella montoucheti (Quitete, 1971) is redescribed based on newly collected specimens from red and brown algae and tubiculous polychaete colony that were obtained from shallow waters at Tamboretes Archipelago, Balneário Barra do Sul and Sepultura Beach, Bombinhas, Santa Catarina State, Brazil. Of 10 species of Pseudaeginella so far reported, Pseudaeginella montoucheti is closest to Pseudaeginella sanctipauli Laubitz, 1995, but differs from the latter by having more numerous body spines including ventro-lateral ones over gills on pereonites 3 and 4, and the antenna 1 length measuring half body length. An identification key for Pseudaeginella species and a checklist of Caprellidea occurring along the Brazilian coasts are also presented.

Chave de identificação para caprelídeos (Crustacea, Amphipoda) do litoral dos Estados do Paraná e de Santa Catarina

An identification key was produced for caprellid species recorded from the coast of Parana and Santa Catarina states, Southern Brazil. Analyzed specimens are part of scientific collections or were obtained from nature, within these states. Nine caprellid belonging to the family Caprellidae, from which eight of Caprellinae - Caprella danilevskii, Caprella dilatata, Caprella equilibra, Caprella penantis, Caprella scaura, Mayerella sp., Paracaprella pusilla e Pseudaeginella montoucheti - and one Phtisicinae - Phtisica marina - were treated in the present study.

Asynchronous Hatching and Extended Parental Care in Aegla schmitti (Decapoda, Anomura)

The aim of this study was to describe the behavior of newly-hatched juveniles and maternal care in Aegla schmitti. The experiment was conducted using seven ovigerous females with eggs at different stages of embryonic development and 12 eggs that had been placed in a separate aquarium. We observed asynchronous hatching in all females, with a mean of 66 hatched juveniles per female. The females also exhibited extended maternal care, allowing the juveniles to remain inside their abdominal chamber or on other parts of their body in the first few days after hatching. The juveniles that hatched in a separate aquarium fed on the remaining eggs, despite food being available. The incubation period and number of hatched eggs are highly variable between species with direct development, with no clear pattern being evident. However, asynchrony in hatching time is apparently common among freshwater anomurans, most likely due to the environmental conditions in which they live. Parental care is an important trait for crustaceans that live in osmotically unfavorable environments, such as freshwater, increasing the survival rate of juveniles.

A new caprellid species (Crustacea: Amphipoda: Senticaudata) from Brazil

A new species of caprellid, Pseudaeginella arraialensis, is described from Arraial do Cabo, Rio de Janeiro, Brazil. Abundant material was collected in Praia do Forno, associated to hydroids and algae of natural rocky substrata and fouling communities of artificial floating structures. The new species can be distinguished easily from the remaining species in the genus mainly by the pattern of dorsal projections, and by the setose antennae and gnathopod 2 in males. The dietary analysis revealed that the species is omnivorous, with a high contribution of small crustaceans in its diet. Detailed figures showing ontogenetic development and intraspecific variation of P. arraialensis are also included.

Studying exotics in their native range: Can introduced fouling amphipods expand beyond artificial habitats?

Knowledge of the habitat use patterns of introduced species in their native or naturalized range can provide unique insights into processes of secondary dispersal and colonization of natural habitats. Caprellid amphipods are small mobile marine epibionts with limited natural dispersal. The global distribution of some caprellid species is mostly the result of anthropogenic transport; however, their subsequent spread beyond artificial habitats is poorly understood. A biogeographic approach, mainly focused on the native-range ecology of introduced and common fouling caprellid amphipods of southern Europe, was used to understand the implications of habitat use patterns for predicting their spread in the introduced regions. Specifically, abundance and composition of caprellid populations were compared among different primary habitats including artificial (floating pontoons), sheltered and wave-exposed rocky shores along the southern and southeastern coasts of Brazil. The findings indicated that artificial habitats act as reservoirs for globally distributed species in both their native and introduced ranges, while endemic species are more scarcely represented. Environmental conditions provided by primary habitats appear important in structuring caprellid assemblages on secondary substrata (basibiont species). Most wide-ranging caprellids were negatively correlated with the level of wave exposure, being more abundant in sheltered (artificial or natural) than in exposed habitats. In this context, Caprella scaura and Paracaprella pusilla, the two introduced caprellids recorded in the Mediterranean, where they are virtually restricted to artificial habitats, may become established in sheltered and even highly polluted natural habitats but hardly colonize wave-exposed rocky shores.