Morfología del la primera zoea del cangrejo Calappa granulata (Linnaeus, 1758) (Brachyura, Calappidae) obtenida en el laboratorio

The first zoeal stage of the calappid crab Calappa granulata is described and illustrated from laboratory-reared material obtained from an ovigerous female captured in the western Mediterranean. The morphology of this larval stage is clearly different from previous description from plankton-collected specimens attributed to this species. The present stage is compared with those previously described from other species of the genus Calappa.En el presente trabajo se describe el primer estadio larvario del cangrejo Calappa granulata. Las larvas se obtuvieron a partir de una hembra ovígera capturada en el Mediterráneo occidental. La morfología de la primera zoea es claramente diferente a la anterior descripción realizada a partir de ejemplares obtenidos en el plancton, y que fue atribuida a C. granulata. La primera zoea de esta especie es comparada con la de otras especies descritas del género Calappa

Identificación de las especies europeas del género Maja (Decapoda: Brachyura: Majidae): análisis de PCR-RFLP de una región del mtADN COI y consideraciones morfológicas

Four species of crabs of the genus Maja have been described along the European coast: M. brachydactyla, M. squinado, M. goltziana and M. crispata. The commercially important species M. brachydactyla and M. squinado achieve the largest body sizes and are the most similar in morphology, and are therefore easily confused. The four species of Maja were identified using a novel morphometric index and a polymerase chain reaction followed by restriction fragment length polymorphism analysis (RFLP). The relationship between carapace length and the distance between the tips of antorbital spines was used to distinguish adults of M. brachydactyla and M. squinado. PCR-RFLP analysis of a partial sequence of the mitochondrial cytochrome oxidase type I (COI) revealed that the four species of the genus Maja can be unambiguously discriminated using the combination of restriction endonucleases enzymes HpyCH4V and Ase I. The molecular identification may be particularly useful in larvae, juvenile and young crabs, when the morphological differences found in adults are not applicable.Cuatro especies del género Maja han sido descritas en las costas europeas: M. brachydactyla, M. squinado, M. goltziana y M. crispata. Las especies M. brachydactyla y M. squinado, que tienen importancia comercial, alcanzan los tamaños más grandes y son morfológicamente muy similares, siendo muy fácil confundirlas. La identificación de las cuatro especies se ha realizado utilizando un nuevo índice morfométrico y un análisis de polimorfismos de fragmentos de restricción (RFLP). La relación entre la longitud del cefalotórax y la distancia entre los extremos distales de las espinas antorbitales se ha utilizado para la diferenciación de los adultos de M. brachydactyla y M. squinado. El análisis PCR-RFLP de una secuencia parcial de la citocromo oxidasa tipo I mitocondrial (COI) indica que las cuatro especies del género Maja pueden ser discriminadas usando una combinación de las endonucleasas HpyCH4V y Ase I. La identificación molecular puede ser particularmente útil en las larvas, juveniles y cangrejos jóvenes, cuando las diferencias morfológicas encontradas en los adultos no son aplicables

A molecular method for the detection of sally lightfoot crab larvae (Grapsus grapsus, Brachyura, Grapsidae) in plankton samples

The decapod Grapsus grapsus is commonly found on oceanic islands of the Pacific and Atlantic coasts of the Americas. In this study, a simple, quick and reliable method for detecting its larvae in plankton samples is described, which makes it ideal for large-scale studies of larval dispersal patterns in the species

Identification of European species of <i>Maja</i> (Decapoda: Brachyura: Majidae): RFLP analyses of COI mtDNA and morphological considerations

Four species of crabs of the genus Maja have been described along the European coast: M. brachydactyla, M. squinado, M. goltziana and M. crispata. The commercially important species M. brachydactyla and M. squinado achieve the largest body sizes and are the most similar in morphology, and are therefore easily confused. The four species of Maja were identified using a novel morphometric index and a polymerase chain reaction followed by restriction fragment length polymorphism analysis (RFLP). The relationship between carapace length and the distance between the tips of antorbital spines was used to distinguish adults of M. brachydactyla and M. squinado. PCR-RFLP analysis of a partial sequence of the mitochondrial cytochrome oxidase type I (COI) revealed that the four species of the genus Maja can be unambiguously discriminated using the combination of restriction endonucleases enzymes HpyCH4V and Ase I. The molecular identification may be particularly useful in larvae, juvenile and young crabs, when the morphological differences found in adults are not applicable

Micro-computed tomography and histology to explore internal morphology in decapod larvae

Traditionally, the internal morphology of crustacean larvae has been studied using destructive techniques such as dissection and microscopy. The present study combines advances in microcomputed tomography (micro-CT) and histology to study the internal morphology of decapod larvae, using the common spider crab (Maja brachydactyla Balss, 1922) as a model and resolving the individual limitations of these techniques. The synergy of micro-CT and histology allows the organs to be easily identified, revealing simultaneously the gross morphology (shape, size, and location) and histological organization (tissue arrangement and cell identification). Micro-CT shows mainly the exoskeleton, musculature, digestive and nervous systems, and secondarily the circulatory and respiratory systems, while histology distinguishes several cell types and confirms the organ identity. Micro-CT resolves a discrepancy in the literature regarding the nervous system of crab larvae. The major changes occur in the metamorphosis to the megalopa stage, specifically the formation of the gastric mill, the shortening of the abdominal nerve cord, the curving of the abdomen beneath the cephalothorax, and the development of functional pereiopods, pleopods, and lamellate gills. The combination of micro-CT and histology provides better results than either one alone.Financial support was provided by the Spanish Ministry of Economy and Competitiveness through the INIA project (grant number RTA2011-00004-00-00) to G.G. and a pre-doctoral fellowship to D.C. (FPI-INIA)

Systematic and Evolutionary Insights Derived from mtDNA COI Barcode Diversity in the Decapoda (Crustacea: Malacostraca)

Background: Decapods are the most recognizable of all crustaceans and comprise a dominant group of benthic invertebrates of the continental shelf and slope, including many species of economic importance. Of the 17635 morphologically described Decapoda species, only 5.4% are represented by COI barcode region sequences. It therefore remains a challenge to compile regional databases that identify and analyse the extent and patterns of decapod diversity throughout the world. Methodology/Principal Findings: We contributed 101 decapod species from the North East Atlantic, the Gulf of Cadiz and the Mediterranean Sea, of which 81 species represent novel COI records. Within the newly-generated dataset, 3.6% of the species barcodes conflicted with the assigned morphological taxonomic identification, highlighting both the apparent taxonomic ambiguity among certain groups, and the need for an accelerated and independent taxonomic approach. Using the combined COI barcode projects from the Barcode of Life Database, we provide the most comprehensive COI data set so far examined for the Order (1572 sequences of 528 species, 213 genera, and 67 families). Patterns within families show a general predicted molecular hierarchy, but the scale of divergence at each taxonomic level appears to vary extensively between families. The range values of mean K2P distance observed were: within species 0.285% to 1.375%, within genus 6.376% to 20.924% and within family 11.392% to 25.617%. Nucleotide composition varied greatly across decapods, ranging from 30.8 % to 49.4 % GC content. Conclusions/Significance: Decapod biological diversity was quantified by identifying putative cryptic species allowing a rapid assessment of taxon diversity in groups that have until now received limited morphological and systematic examination. We highlight taxonomic groups or species with unusual nucleotide composition or evolutionary rates. Such data are relevant to strategies for conservation of existing decapod biodiversity, as well as elucidating the mechanisms and constraints shaping the patterns observed.FCT - SFRH/BD/25568/ 2006EC FP6 - GOCE-CT-2005-511234 HERMESFCT - PTDC/MAR/69892/2006 LusomarBo