-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.
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.
ABSTRACT. Sexual dimorphism in Hepatus pudibundus (Crustacea, Decapoda: Brachyura). A study on sexual dimorphism in Hepatus pudibundus (Herbst, 1785) was performed using geometric morphometrics. The carapace of 28 males and 30 females and the left and right cheliped propodus of 22 males and 26 females were analyzed. Thirteen landmarks were established in the carapace and 10 in the cheliped propodus. A Generalized Procrustes Analysis based on landmark confi gurations was used to separate the components of size and shape. A Student t-test was used to determine the statistically signifi cant sexual dimorphism of the carapace and the cheliped propodus. The variation in the shape of the structures was evaluated with a discriminant analysis. There was sexual dimorphism in the analyzed structures. Males were smaller than females. The carapace of females was larger in the posterior region than in males, indicating an expansion of the area for accommodation of the egg mass. The fi xed fi nger of the cheliped propodus of females is more posteriorly arched that can be used to facilitate the cleaning of eggs laid in the abdominal chamber. Our results provide new information about the development of sexual secondary characters and their eff ects on the shape of the carapace and the cheliped propodus in males and females of H. pudibundus.KEYWORDS. Aethridae, carapace, propodus, geometric morphometrics, morphological variation.RESUMO. Um estudo sobre o dimorfi smo sexual no caranguejo Hepatus pudibundus (Herbst, 1785) foi realizado utilizando morfometria geométrica. A carapaça de 28 machos e 30 fêmeas e o própodo dos quelípodos direito e esquerdo de 22 machos e 26 fêmeas foram analisados. Foram estabelecidos 13 marcos anatômicos bidimensionais na carapaça e 10 no própodo para ambos os sexos. Uma Análise Generalizada de Procrustes baseada na confi guração dos marcos anatômicos foi utilizada para separar os componentes de tamanho e de forma. Um Teste-t de Student foi utilizada para determinar a signifi cância estatística do dimorfi smo sexual da carapaça e do própodo dos quelípodos. A variação na forma das estruturas foi avaliada através de uma Análise de Função Discriminante. Houve dimorfi smo sexual na forma e no tamanho das estruturas analisadas. Machos mostraram dimensões menores do que fêmeas. A carapaça das fêmeas foi mais larga na região posterior do que em machos, indicando uma ampliação da área para acomodação da massa de ovos. O dedo fi xo do própodo dos quelípodos das fêmeas está mais voltado para a parte posterior e pode facilitar a limpeza dos ovos fi xados na câmara abdominal. Nossos resultados trazem novas informações sobre o desenvolvimento de caracteres sexuais secundários e as suas consequências sobre a forma da carapaça e o própodo dos quelípodos em machos e fêmeas de H. pudibundus.PALAVRAS-CHAVE. Aethridae, carapaça, própodo do quelípodo, morfometria geométrica, variação morfológica.A dimorfismo sexual pode ser definido como diferenças morfológicas entre os sexos que estão relacionados principalmente à seleçã...
The genetic and morphometric population structures of the semiterrestrial crab Armases angustipes from along the Brazilian coast were examined. The influence of the Central South Equatorial Current on larval dispersal of A. angustipes also was evaluated. Six populations were sampled from estuarine areas in São Luis do Maranhão, Maranhão; Natal, Rio Grande do Norte; Maceió, Alagoas; Ilhéus, Bahia; Aracruz, Espírito Santo; and Guaratuba, Paraná. Patterns of genetic differentiation were assessed using DNA sequence data corresponding to parts of the mitochondrial cytochrome c oxidase subunit 1. Geometric morphometric techniques were used to evaluate morphological variation in shape and size of the carapace and right cheliped propodus. Our results revealed low genetic variability and lack of phylogeographic structure; geometric morphometrics showed statistically significant morphological differentiation and geographic structuring. Our data indicate the absence of possible barriers to gene flow for this mobile species, and no clear correlation of morphological or genetic variation with ocean currents and/or geographic distance. Our results also suggest that historical geological and climatological events and/or possible bottleneck effects influenced the current low genetic variability among the populations of A. angustipes.
The first stage of the fiddler crab Minuca mordax is described here. Zoea larvae obtained from four ovigerous female were reared in the laboratory until the development of the first crab stage. The development from zoea I to the first juvenile instar lasted 35 days after hatching. The first crab stage of Minuca mordax can be morphologically distinguished from those of Minuca burgersi and Leptuca cumulanta by a 2-segmented antennule endopod (3-segmented in M. burgersi, unsegmented in L. cumulanta), an unsegmented maxillule endopod (2-segmented in M. burgersi and L. cumulanta), and a 4-segmented first and second maxilliped endopod (respectively unsegmented and 5-segmented in M. burgersi and L. cumulanta). The three species have the following characters in common: segmented peduncle of antennule 2; endopod of antennule unsegmented; presence of aesthetascs on the antennule; peduncle of antenna 3-segmented; flagellum of antenna 6-segmented; mandible 3-segmented; maxilla with coxal and basal endite bilobed; first, second and third maxillae with exopod 2-segmented and abdomen with six somites that are wider than long.
Trevisan, A., Marochi, M.Z., Costa, M., Santos, S. and Masunari, S. 2014. Effects of the evolution of the Serra do Mar mountains on the shape of the geographically isolated populations of Aegla schmitti Hobbs III, 1979 (Decapoda: Anomura). -Acta Zool ogica (Stockholm) 00:000-000The Aeglidae family is a useful model for evaluating the shape variation to present small geographically isolated populations and present a carapace structure that allows precise placement of landmarks. We analysed variations of the size and shape of the carapace of seven populations of A. schmitti. We used 18 bidimensional anatomical landmarks on the carapace of adult males. Size variation between the populations was analysed through a univariate analysis of variance, while the shape variation was analysed through a multivariate analysis of variance using the configurations aligned by the generalized Procrustes analysis. The ordination of the populations was investigated through a canonical variables analysis. Individuals from the populations differed in the carapace size, in this case, we observed the largest individuals in the Iguac ßu river basin, followed by Ribeira do Iguape and the Coastal basin. Carapace shape also differed between the populations of A. schmitti, with the exception of the Mato Grande and Piraquara rivers: populations from the Iguac ßu River presented a larger and rounder carapace when compared with the slenderer carapace of the Coastal basin, and the Ribeira do Iguape animals presented intermediate shapes. Data from the present study show great congruency with the draining pattern and geological history of the region.Andr e Trevisan, Departamento de Zoologia, Programa de P os-Graduac ßão em Zoologia, Universidade Federal do Paran a. Centro Polit ecnico, Jardim das Am ericas,
A pictorial species identification key for crabs of the families Eriphiidae, Menippidae, Panopeidae and Pilumnidae from shallow waters of Paraná State coast was elaborated. A description of the recognition characteristics and illustrations of the species are also presented. Crab samples were obtained from mangrove, estuary and oyster farming located in Guaratuba Bay and rocky shore in Matinhos city. Drawings and analyses were based on freshly collected specimens and on those deposited at Natural History Museum of Capão da Imbuia and at Laboratory of Ecology of Crustacea UFPR. A total of 13 species were analyzed, from which nine species of Panopeidae, two Pilumnidae and one of Eriphiidae and Menippidae. This species richness was considered similar to neighboring areas in spite of the short extension of the Paraná State coast. Resumo: Uma chave pictórica de identificação foi elaborada para as espécies de caranguejos das famílias Eriphiidae, Menippidae, Panopeidae e Pilumnidae ocorrentes em águas rasas do litoral do Estado do Paraná. Uma descrição das características de reconhecimento e figuras das espécies também são apresentadas. Exemplares vivos foram obtidos de manguezal, estuário e cultivo de ostras na Baía de Guaratuba e costão rochoso de Matinhos. Os desenhos e a análise foram baseados nos exemplares coletados recentemente e naqueles depositados no Museu de História Natural do Capão da Imbuia e no Laboratório de Ecologia de Crustacea UFPR. Um total de 13 espécies foi analisado, das quais nove de Panopeidae, duas de Pilumnidae e uma de Eriphiidae e Menippidae. Esta riqueza de espécies foi considerada similar à das áreas vizinhas, apesar da curta extensão do litoral do Estado do Paraná. Palavras-chave: caranguejos, chave de identificação, Brachyura, Paraná, Brasil.
Differences between sexes may arise either during development or at the adult stage only. In both cases growth rate during development and level of allometry may influence sexual dimorphism and ontogenetic trajectories. To analyse the period in which sexual dimorphism appears during ontogeny and assess allometric ontogeny in Sesarmidae crabs, we evaluated: (1) sexual dimorphism in shape and size of the carapace and cheliped propodus of juveniles and adultAratus pisoniiandArmases rubripes, and (2) their ontogenetic trajectory, using geometric morphometric (GM) techniques. We tested the hypothesis that sexual dimorphism in sesarmid crab shape takes place before the puberty moult. InAratus pisoniithere was sexual dimorphism in the shape of the carapace in juveniles (before puberty moult) and variation between juveniles and adults was size-dependent, especially in the frontal region of the carapace. ForArmases rubripesthis shape sexual dimorphism was detected only after the puberty moult (adult phase). For males, carapace variation between juveniles and adults was also size-dependent, especially in the carapace frontal region, but for females, there was a change in shape with different trajectories. Our results also indicated that shape variation is a common pattern during growth for Sesarmidae species. This ontogenetic shape variation may be associated with spatial partitioning between juveniles and adults.
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