André Trevisan

Sexual dimorphism in Aegla marginata (Decapoda: Anomura)

A study on sexual dimorphism in Aegla marginata was conducted using geometric morphometric methods. The carapace of 47 females and 75 males and the left and right cheliped propodus of 29 females and 40 males were analyzed. Eighteen landmarks were established in the carapace and 10 in the cheliped propodus. A Generalized Procrustes Analysis based on landmark configurations was used to separate the components of size and shape. A Student t-test was used to determine whether statistically significant sexual dimorphism was shown by the carapace and the cheliped propodus. The variation in the shape of the structures was evaluated with a discriminant analysis. Our results show that there is no sexual dimorphism in the carapace of A. marginata. However, the size of the propodus differed statistically between the sexes. The carapace shape differed between the sexes: the females showed a wider posterior area and a narrower anterior area than the males. The shape of the cheliped propodus also differed between the sexes: overall, the females had a longer and narrower cheliped propodus than the males. The variations in the carapace shape found in this study confirm the results of other studies on aeglid morphology; however, the information presented by this study regarding variation in the shape of the cheliped propodus is new to the literature. The geometric morphometric approach applied in this study provided useful tools for achieving the proposed objectives.

Morphological Sexual Maturity, Sexual Dimorphism and Heterochely in Aegla Manuinflata (Anomura)

ABSTRACT This study investigated the use of morphometric aspects of Aegla manuinflata Bond-Buckup and Santos, 2009 to determine the mean size of males and females at the onset of sexual maturity and to test for intraspecific sexual variations. The programs Mature I and Mature II were used to analyze relative growth. Relationships reflecting the onset of morphological sexual maturity were tested with the software REGRANS, as a means of comparing methodologies. The mean size at first maturity was estimated as 13.60 mm CL in males and 10.84 mm CL in females. The Principal Components Analysis showed that the dimensions of the chelipeds propodus length were primarily responsible for the total variance in the data for males and females. The Discriminant Function Analysis showed that there were no significant differences among juveniles; however, adult males and females were distinguished as two separate groups, indicating that sexual maturity in this species probably occurs after a single ecdysis. Aegla manuinflata shows heterochely, with the left cheliped being the larger in all categories. This seems to be a general pattern for members of Aeglidae.

Intraspecific Morphological Variation in a Freshwater Crustacean Aegla Plana in Southern Brazil: Effects of Geographical Isolation on Carapace Shape

ABSTRACT Freshwater ecosystems are characterized by a high spatial complexity. This heterogeneity affects the distribution of aquatic organisms in riverine landscapes. Morphological variation in natural populations is driven by evolutionary forces. In crustaceans, morphological variations have been observed between different basins, environments, or developmental sequences along their geographical distribution. In this study, we assessed the possible effects of spatial scale on the phenotype of Aegla plana Buckup and Rossi, 1977 using geometric morphometrics. We examined 110 adult specimens from three river basins in southern Brazil. We used 13 morphological landmarks for the dorsal view of the carapace; the coordinates were superimposed using a generalized Procrustean analysis. We used a multivariate analysis to test the morphological variation in crabs from different basins, and we employed the Mantel test to assess the relationship of spatial and environmental factors with the principal components matrix for the carapace shape. Populations from different river basins differed significantly in carapace centroid size. Carapace shapes also differed significantly among the river-basin populations, and the interaction between sex and populations was also significant. The environmental and geographical matrices were correlated with the carapace shape matrix. This morphological variation shows an association with the geographical distribution of microbasins, which suggests a biogeographical effect on the distribution of A. plana.

Chemistry compound dynamic of leaf-litter and fauna associated with breakdown process of arboreous species in a stream from North of Rio Grande do Sul, Brazil

The present study aimed at evaluating the concentrations of chemistry compounds in leaf-litter during the breakdown process, and the colonization of Sebastiania commersoniana (Baill.) Smith and Downs and Eucalyptus grandis Hill ex Maiden for aquatic invertebrates, as well as verifying the influence of breakdown process in native and exotic species of the aquatic fauna. There were incubated 28 litterbags in a first order stream in Erechim, RS, Brazil. After 1, 3, 7, 15, 30, 45 e 60 days of breakdown, we determined polyphenols contends, nitrogen e total phosphorous of the leaf-litter remanecent material. The colonizing fauna of the leaf-litter was quantified in the same periods. The results showed no significant difference in the leaf-litter compounds liberation. Breakdown of E. grandis was slower than S. commersoniana . The contents of polyphenols showed more importance for the colonization of the S. commersoniana . The more slowly liberation of compounds by E. grandis leaves is probably due to more difficulty in fragmenting the organic debris. The aquatic invertebrates that colonized the E. grandis debris showed that their presence or absence was more associated with the nitrogen concentrations. Key words: leaf-litter, macroinvertebrates, Sebastiania commersoniana , Eucalyptus grandis .

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.

Compostos secundários durante a decomposição foliar de espécies arbóreas em um riacho do sul do Brasil

RESUMO – (Compostos secundarios durante a decomposicao foliar de especies arboreas em um riacho do sul do Brasil). Os objetivosdeste trabalho foram identificar os compostos secundarios e avaliar o comportamento destes em folhas de Sebastiania commersoniana(Baill.) Smith e Downs e Eucalyptus grandis Hill ex Maiden durante diferentes estagios de decomposicao em um riacho de primeira ordemdo norte do Rio Grande do Sul. Foram incubadas no riacho folhas das duas especies, sendo essas retiradas do corpo hidrico apos zero,um, 30 e 60 dias para determinacao da taxa de decomposicao e analise quimica por cromatografia gasosa. Foi possivel identificar 14compostos em S. commersoniana e 25 em E. grandis. O acido palmitico foi o composto mais frequente em ambas as especies durante oexperimento, sendo que a quantidade deste e dos demais compostos identificados variou durante o periodo estudado. A complexidadequimica das folhas de E. grandis pode ter influenciado na sua decomposicao, que foi mais lenta que a das folhas de S. commersoniana.Palavras-chave: Eucalyptus grandis , qualidade ambiental, Sebastiania commersoniana , vegetacao ribeirinhaABSTRACT – (Secondary compounds during leaf decomposition of tree species in a stream in southern Brazil). This work aims toidentify the secondary compounds and evaluate their behaviour in Sebastiania commersoniana (Baill.) Smith and Downs (Euphorbiaceae)and Eucalyptus grandis Hill ex Maiden (Myrtaceae) leaves during different decomposition stages in a first-order stream in northern RioGrande do Sul. Leaves of the two species were incubated in the stream and were removed after 0, 1, 30 and 60 days to determinedecomposition rate and perform chemical analysis by gas chromatography. Fourteen compounds in S. commersoniana and 25 in E.grandis were identified. Palmitic acid was the most frequent compound in both species throughout the experiment; the amount of thisacid and the other compounds varied during the study period. The chemical complexity of E. grandis leaves may have influenced theirdecomposition, which was slower than that of S. commersoniana leaves.Key words: environmental quality, Eucalyptus grandis, riparian vegetation, Sebastiania commersoniana

Abundância e distribuição de Aeglidae (Crustacea: Anomura) em função do uso da terra na bacia hidrográfica do Rio Jacutinga, Rio Grande do Sul, Brasil

This study investigated the influence of land use and occupation on the density and distribution of aeglids in the hydrographic basin of the Jacutinga river (northern state of Rio Grande do Sul, Brazil). Sampling was carried out during the summer and winter of 2004, at 12 sites distributed in river spring, agriculture, grazing, and urban areas. Animals were collected using a Surber sampler. An analysis of variance (ANOVA) was conducted to evaluate differences in the density of species in each land use and sampling period. Biological data were classified using cluster analysis (Euclidian distance; UPGMA). A total of 226 aeglids were captured, including 167 (78.89%) specimens of Aegla platensis Schmitt, 1942 and 59 (26.11%) specimens of A. singularis Ringuelett, 1948. The aeglid distribution was associated with land use and occupation. In river spring and grazing areas, A. platensis was predominant, whereas in urban and agricultural areas A. singularis was the most prevalent species.

Crescimento de Aegla manuinflata (Decapoda, Anomura, Aeglidae) em ambiente natural

The aim of this work was to evaluate the growth of Aegla manuinflata Bond-Buckup & Santos, 2009 in natural environment. Samplings were monthly performed, from April/2006 to May/2007, in a tributary of Ibicui-Mirim River, which belongs to the Uruguay River basin, at Sao Pedro do Sul municipality, state of Rio Grande do Sul, Brazil. Traps and dip nets were used to collect the animals. The specimens were sexed and had their cephalothoracic length (CL) measured, using a digital caliper with 0.01 mm precision. The growth was evaluated using the von Bertalanffy model. The growth curves in length (mm), for the data obtained through the modal progression, are described by the equations: Ct = 28.00 [1 - e-0.0047(t+10.63)] for males and Ct = 25.16 [1 - e-0.0051(t+17.65)] for females. The maximum estimated age for males was three years and for females was two years and six months.

Morphological variation in the sexual maturity of three sympatric aeglids in a river in southern Brazil

The objective of this study was to investigate the use of morphometric aspects of three sympatric aeglids (Aegla platensis, Aegla grisella, and Aegla ludwigi) to determine the mean size of males and females at the onset of sexual maturity and verify whether there are differences at sexual maturity between the species. The relationships between CL and cheliped dimensions for males and CL and AW for females reflecting the onset of morphological sexual maturity were tested using the software REGRANS. The intersections between the lines of allometric growth for juveniles and adults were tested using an analysis of covariance (ANCOVA). In males and females, the growth rate was positively allometric. The analysis of juveniles and ovigerous females showed that they breed year round. The three sympatric aeglids reached the onset of sexual maturity at different sizes, which may facilitate the coexistence of all species.

Population dynamics of Aegla manuinflata Bond-Buckup and Santos 2009 (Decapoda: Aeglidae), an threatened species

AIM: We evaluate the population density, median size of males and females, age distribution, sex-ratio, reproductive period and recruitment period of the threatened species Aegla manuinflata. METHODS: Monthly samplings were made from May 2006 to April 2007 in the Passo Taquara stream, Brazil. An extra sampling was performed at each season of the year in order to determine population density. Animals were captured with traps and handnets. All the captured specimens were sexed and had their cephalotoraccic length measured with a digital caliper (0.01 mm), and were then released back in the stream. RESULTS: A total of 888 individuals were analyzed, including 17 unsexed juveniles, 572 males, 274 females and 25 ovigerous females. A mean population density of 1.52 ind/m2 was estimated. Males showed median sizes larger than females (p 0.05). Males and females caught only with handnet follow the expected 1:1 proportion in all months of the year (p > 0.05), demonstrating that the sampling method clearly affects the results. Ovigerous females and juveniles were registered in all seasons of the year and there is no significant different in the proportion of these animals among the seasons (p > 0.05), indicating continuous reproduction. CONCLUSIONS: Population data of this study can be used as a basis for the creation of conservation measures of A. manuinflata, since the species is considered vulnerable.