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Megalopas of 15 brachyuran crab species collected in the open sea plankton, and unknown until now, were identified using DNA barcodes (COI and 16S rRNA). Specimens belonging to the families Portunidae, Pseudorhombilidae and Xanthidae (Crustacea, Decapoda, Brachyura), and corresponding to the species Achelous floridanus, Arenaeus mexicanus, Callinectes amnicola, C. arcuatus, C. ornatus, C. toxones, Charybdis (Charybdis) hellerii, Portunus hastatus, Thalamita admete, Scopolius nuttingi, Etisus odhneri, Liomera cinctimanus, Neoliomera cerasinus, Pseudoliomera variolosa, and Williamstimpsonia stimpsoni, are described and illustrated, and compared with other congeneric species previously described. We also provide a new geographical record for N. cerasinus and the most remarkable features for each species., The Ministry of Economy and Competitiveness of Spain (MINECO) and the European Fund for Economic and Regional Development (FEDER) through the MALASPINA 2010 Expedition (Consolider-Ingenio 2010, CSD2008-00077) and MAF Research Project (National Research Program, CTM2012-39587-C04-02) funded this study. We thank the captains and crews of RV Hespérides in 2010-11 and 2015 for the support during the cruises, and Carlos Sánchez (ICMAN-CSIC) by laboratory work.

14 pages, 6 figures, 1 table, DNA methods may contribute to better understand larval dispersal of marine lobsters. The molecular analysis of phyllosoma specimens from the East Atlantic facilitated for the first time here the description of Scyllarus subarctus Crosnier, 1970 larvae. The identification of S. subarctus phyllosomae from Cabo Verde confirmed that this species has a much wider geographic distribution than previously thought. Moreover, the phylogenetic analyses placed S. depressus from the Western Atlantic together with the African species S. subarctus, instead of other American Scyllarus. In fact, S. depressus and S. subarctus formed a strongly supported clade with comparatively low genetic differentiation, suggesting the possibility that they might be recently-diverged sister taxa with an amphi-Atlantic distribution. Support for this is provided by the examination of S. subarctus larvae and the lack of any qualitative character that would allow for differentiation between the adults of S. subarctus and S. depressus. The results obtained highlight the challenges of current Scyllarus systematics and the need for further research on Atlantic slipper lobsters, This research was funded by projects CHALLENGEN (CTM2013-48163) and MAFIA (CTM2012-39587-C04-02) of the Spanish Government and EU-Synthesys grants (DK-TAF-4873: Morphological study of Achelata lobsters and phyllosoma larvae from Danish collections and FR-TAF-5980: Description of phyllosoma stages of West-African lobster species). FP acknowledges project FP7 Marie Curie IAPP #324475 ‘Colbics’ of the European Union and a post-doctoral contract funded by the Beatriu de Pinos Programme of the Generalitat de Catalunya.

14 pages, 9 figures, 5 tables, Surface waters are an attractive foraging ground for small fish in the open ocean. This study aims to determine the importance of vertically migrating species in the neuston of oceanic waters across the Atlantic, Indian and Pacific Oceans and to ascertain the influence of environmental variables on their distribution patterns. Neustonic fish assemblages were primarily controlled by light. They were dominated by late-larvae and juveniles of Exocoetidae, Hemiramphidae and Scomberesocidae during the day. At night, the vertical migration of mesopelagic species changed the dominance pattern in favour of Myctophidae and Scomberesocidae. The neustonic families’ distribution was primarily related to sea surface temperatures, whereas environmental variables at deeper layers were related to mesopelagic migrating families. Canonical correspondence analysis showed a low but statistically significant contribution of several environmental variables to myctophid species composition (10%), with minimum oxygen concentrations ranking first in variance explanation followed by maximum fluorescence, sea surface temperature and 400-m temperature. Spatial autocorrelation also explained 17% of the variance, indicating the influence of other factors such as historical, demographic and dispersal constraints. The low number of myctophid species in the North Pacific Equatorial Countercurrent appears to be related to the low oxygen concentrations observed in this province, This study was financed by the Spanish Ministry of Economy and Competitiveness (Consolider-Ingenio 2010, CSD2008-00077 and CTM2012–39587-C04–03)

The complete larval development and the morphology of the first juvenile stages of two freshwater-breeding crab species endemic to Jamaica are described and illustrated in detail in the present paper. One of these species, Sesarma windsor, lives in and near caves in the karst regions of central western Jamaica, whereas the second species, Metopaulias depressus, occurs sympatrically but with a wider range in western and central Jamaica in water-filled leaf axils of bromeliads. Even if these species are placed in separate genera, they are extant representatives of the same adaptive radiation that resulted in at least ten Jamaican endemic crab species thriving in different land-locked habitats. Consequently, larval morphologies of the two species are very similar, but conspicuously different from the developmental patterns in their marine relatives. Both species display an abbreviated mode of development, showing morphological reductions in some features and pre-displacement in the expression of sev...

Axayacatl Molina-Ramírez et al., © 2015 The Author. We have supplemented available, concurrent measurements of fresh weight (W, g) and body carbon (C, g) (46 individuals, 14 species) and nitrogen (N, g) (11 individuals, 9 species) of marine gelatinous animals with data obtained during the global ocean MALASPINA 2010 Expedition (totalling 267 individuals and 33 species for the W versus C data; totalling 232 individuals and 31 species for the N versus C data). We then used those data to test the allometric properties of the W versus C and N versus C relationships. Overall, gelatinous organisms contain 1.13 ± 1.57% of C (by weight, mean ± SD) in their bodies and show a C:N of 4.56 ± 2.46, respectively, although estimations can be improved by using separate conversion coefficients for the carnivores and the filter feeders. Reduced major axis regression indicates that W increases isometrically with C in the carnivores (cnidarians and ctenophores), implying that their water content can be described by a single conversion coefficient of 173.78 gW(g C)-1, or a C content of 1.17 ± 1.90% by weight, although there is much variability due to the existence of carbon-dense species. In contrast, W increases more rapidly than C in the filter feeders (salps and doliolids), according to a power relationship W = 446.68C1.54. This exponent is not significantly different from 1.2, which is consistent with the idea that the watery bodies of gelatinous animals represent an evolutionary response towards increasing food capture surfaces, i.e. a bottom-up rather than a top-down mechanism. Thus, the available evidence negates a bottom-up mechanism in the carnivores, but supports it in the filter feeders. Last, N increases isometrically with C in both carnivores and filter feeders with C:N ratios of 3.89 ± 1.34 and 4.38 ± 1.21, respectively. These values are similar to those of compact, non-gelatinous organisms and reflect a predominantly herbivorous diet in the filter feeders, which is confirmed by a difference of one trophic level between filter feeders and carnivores, according to stable N isotope enrichment data., This work was supported by the MALASPINA 2010 Expedition project, funded by the Spanish Ministry of Science and Innovation (MICINN-08-CSD2008-00077) in collaboration with the Spanish Navy and the BBVA foundation. This is a contribution of the Asturias Marine Observatory

Although Parthenopidae is a brachyuran decapod family comprising almost 140 species, there is little knowledge about its larval morphology. There are only two complete larval developments reared in the laboratory and some larval stages described for seven species. In the present work these data are compared and analysed. A summary is made of the larval features that characterize parthenopids that can be used to distinguish them from other brachyuran larvae. In addition, the megalopa stage of Derilambrus angulifrons and Parthenopoides massena was collected from plankton and identified by DNA barcodes. The morphology of the megalopa of D. angulifrons is described for the first time, and that of P. massena is compared with a previous description., The research was carried out within the framework of the projects MEGALOPADN (CGL2009-11225) and ‘Transporte y reclutamiento larvario de crustáceos bentónicos litorales: importancia de los agentes forzadores costeros y regimen mareal’ (CTM2005- 00024/MAR), both co-financed by the ‘Ministerio de Economía y Competividad (MINECO)’ Spanish Plan R + D + I and FEDER. Elena Marco-Herrero acknowledges the pre-doctoral FPI Fellowships supported by MINECO (BES-2010-033297 and EEBB-I-13-07501).

The aim of this study was to assess the effect of temperature on the survival and duration of larval development in the African pea crab Afropinnotheres monodi, as well as to describe its larval stages. We studied larvae reared in the laboratory and also specimens collected from plankton from the Gulf of Cádiz at two different temperatures. According to the results of this study, larval development of A. monodi involves four zoea stages and one megalopa and lasts around 25 days at 25°C, and longer than 40 days at 19°C. Such a temperature-related duration of this dispersive phase may be causing a higher recruitment to parental populations during the summer, but a higher dispersal to new locations during the rest of the year, a seasonal pattern of dispersion which could favour the successful expansion of this non-native species into European waters. The identification of both larval phases from plankton samples and adult specimens was carried out using morphological characters and molecular techniques. Both the 16S mtDNA sequences of this species, now available in GenBank, and the larval descriptions provided by this study could help to establish an early alert for the detection of this African species in its northward expansion., The research was carried out within the framework of the projects MEGALOPADN [CGL2009-11225], ‘Transporte y reclutamiento larvario de crustáceos bentónicos litorales: importancia de los agentes forzadores costeros y regimen mareal’ [CTM2005-00024/MAR] and AFROBIV [CGL2014-53557-P], co-financed by the ‘Ministerio de Economía y Competividad (MINECO)’ Spanish Plan R+D+I and ERDF, European Union. Elena Marco-Herrero acknowledges a pre-doctoral FPI Fellowship supported by MINECO [BES-2010-033297].

The morphology of the megalopa stage of the panopeid Rhithropanopeus harrisii is redescribed and illustrated in detail from plankton specimens identified by DNA barcode (16S mtDNA) as previous descriptions do not meet the current standard of brachyuran larval description. Several morphological characters vary widely from those of other panopeid species which could cast some doubt on the species' placement in the same family. Besides, some anomalous megalopae of R. harrisii were found among specimens reared at the laboratory from zoeae collected in the plankton. These anomalous morphological features are discussed in terms of problems associated with laboratory rearing conditions. © 2014 Springer-Verlag Berlin Heidelberg and AWI., The research was carried out within the framework of the projects MEGALOPADN (CGL2009-11225) and “Transporte y reclutamiento larvario de crustáceos bentónicos litorales: importancia de los agentes forzadores costeros y regimen mareal” (CTM2005-00024/MAR), both co-financed by the “Ministerio de Economía y Competividad (MINECO)” Spanish Plan R + D + I and European Union FEDER funds. Elena Marco-Herrero acknowledges the pre-doctoral FPI Fellowship supported by MINECO (BES-2010-033297).

12 páginas, 8 figuras, 4 tablas., The present study describes the reproductive biology, population structure and life history traits of the abundant intertidal crab Xantho poressa. Between March 2007 and April 2008, a total of 1918 individuals were collected in Corrales de Rota (south-western Spain), a human-modified intertidal habitat characterized by an artificial high complexity. Suitable refuges for crabs (cobbles and boulders) are very abundant in this area and density (maximum of 50 ind*m−2) was directly related with the area covered by these stones. In spring and summer, size–frequency distributions showed a polymodal pattern with seasonal variations related to the incorporation of juveniles to the adult population. Newly settled juveniles were not found in the Corrales suggesting an ontogenetic migration from a distant recruitment habitat. The annual reproductive cycle was seasonal and successive peaks in the abundance of ovigerous females were observed in late spring and summer. Females probably produced multiple broods during a long intermoult period. The gonadosomatic index had a cyclic pattern of variation with peaks two weeks prior to those of ovigerous females; it was lower during the non-reproductive season. The hepatosomatic index was high during spring, decreased during summer and increased gradually at the end of the reproductive season. There was a monthly cycle of larval release resulting from a combination of a cyclic and synchronic ovarian maturity, oviposition and incubation; hatching took place during neap tides when the moon was at last quarter. The adaptive significance of the rhythmic reproduction and hatching observed may not be explained by the predator avoidance hypotheses. The overall sex-ratio did not differ from 1:1 but one male and several females coexist under a stone, indicating a female biased operative sex-ratio. The combination of a complex habitat, its use, and a strong sexual dimorphism suggest a refuge–defence polygenic mating system. The survival and fitness of X. poressa in the Corrales de Rota are probably enhanced by the availability of shelter, a consequence of a highly complex habitat, and probably, of human activity., This study was partially carried out during a 6-month visit by E.D.S. to the Instituto de Ciencias Marinas de Andalucía (ICMAN), supported by the Ministerio de Educación y Ciencia de España (MEC) through a grant for foreign professors and researchers visiting laboratories in Spain during their sabbatical years (SAB2005-0170).