This study simulated the connectivity patterns among 7 coral reef systems in the southern Gulf of Mexico. Two subgroups of reefs were considered: one near the mainland over the narrow western shelf, and the other over the wide Campeche Bank (CB). A particle-tracking module was coupled to a realistic simulation with the Hybrid Coordinate Ocean Model in order to study the transport and dispersion of particles in near surface waters. The simulation consisted of the launch of 100 passive particles (virtual larvae) from each reef, every 24 h over a 5 year period; it considered species lasting up to 35 d in the plankton and assumed no seasonality in reproduction. On the western shelf, connection was northwards from March to August, and southwards from September to February; over the CB edge, the connection was northwestwards throughout the year. Over the western shelf, reefs showed a strong degree of interconnectivity and high particle retention. Higher self-recruitment was most likely due to the passage of synoptic-scale atmospheric systems and their associated changes in wind and current direction. In contrast, CB reefs exhibited lower connectivity and less larval retention. Over the western edge of the Bank, connectivity was almost unidirectional because of the influence of the cyclonic gyre in the Campeche Bay, which causes particles to disperse over a wide area with low probabilities of selfrecruitment. The main connection pathway was the confluence zone between neritic and oceanic waters over the outer shelf of the Bank. Connection between the 2 groups of reefs was weak.

Most coral-associated decapod species have non-migratory adult populations and depend on their planktonic larvae for dispersal. This study examined the metapopulation structure of three decapod species with different pelagic larval duration (PLD) from twelve coral reef complexes of the Gulf of Mexico. The dispersion of larvae was analyzed through the use of a realistic numerical simulation of the Gulf of Mexico with the Hybrid Coordinate Ocean Model. To study the transport and dispersion of particles in near-surface waters, a particle-tracking subroutine was run using as input the currents from the model. The simulation consisted of the launch of 100 passive particles (virtual larvae) every 24 hours from each reef throughout five years, and tracked for as long as 210 days. Results indicated that species with a short PLD, Mithraculus sculptus (PLD 8‒13 days), had a weak connection among the reefs, but higher self-recruitment, especially on the narrow western shelf. The species with a longer PLD, Dromia erythropus (28‒30 days), had a stronger connection among neighboring reefs (< 300 km). Finally, the species with an even longer PLD, Stenopus hispidus (123‒210 days), had a wider potential distribution than the other species. Circulation on synoptic, seasonal and interannual scales had differential effects on the larval dispersal of each species. The metapopulation structure of M. sculptus and D. erythropus seemed to combine features of the non-equilibrium and the patchy models, whereas that of S. hispidus presumably fit to a patchy model. These findings support previous observations that indicate that species with longer PLD tend to occupy larger areas than species with short PLD, although recruitment of juveniles to the adult populations will also depend on other factors, such as the availability of suitable habitats and the ability to colonize them.

In this study the first blind species of Hyalella for Mexico is described; it is the second in the genus to be recorded there. The new species is closer to the eyeless species: H. anophthalma Ruffo, 1957, H. muerta Baldinger, Shepard & Threloff, 2000, H. caeca Pereira, 1989, H. spelaea Bueno & Cardoso, 2011 in Cardoso et al. 2011, H. imbya Rodrigues & Bueno, 2012 in Rodrigues et al. 2012, but with no curved seta at the inner ramus of uropod 1, antennae 1 shorter than antennae 2, no apical setae on the telson and a characteristic dorsoposterior carina and three pappose setae on the inner plate of maxilla 1. The morphological intraspecific variations that can be found in this genus are discussed.

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Information on growth in hermit crabs is very scarce, possibly due to the inherent difficulties of extracting them from their shells. In this work we document the relative growth, sexual size dimorphism, and level of chelae asymmetry of the land hermit crab Coenobita clypeatus (Fabricius, 1787) collected on a coral reef island in the National Park Arrecife Alacranes, southern Gulf of Mexico, during December 2009 and September 2010. Specimens examined were anaesthetized in a clove oil-water solution to avoid unnecessary crab mortality. A total of 387 individuals was measured on six external variables: cephalothorax length and width, and both chelae in length and width. Taking the cephalothorax length as the reference dimension, the remaining measurements were fitted to a power function to examine the degree of allometry in growth and make comparisons between sexes. For each sex, an asymmetry index (AI) was calculated to determine the degree of heterochely, and the significance of its value was evaluated by means of null models. Numerically, males dominated the crab population in the largest size classes (>12.6 mm CL) in both seasons. As in most anomurans, C. clypeatus males attained larger body sizes than females, but their relative growth was most similar. For both sexes, the growth of chela width was positively allometric (t-test, p < 0.05). Also, AI values showed a heterocheleous condition, with the left chela significantly higher (p < 0.001) than the right. Regarding our own results and previous reports, we propose that heterochely could be triggered during the glaucothoal and juvenile stages. Numerical dominance of males in the larger size classes is probably due to the segregation of ovigerous females from the main crab group, searching suitable areas for egg deposition, but also to a better condition of males to carry heavier shells than females, which in their turn have to invest a considerable amount of energy in reproduction. RESUMENLa información sobre el crecimiento de los cangrejos ermitaños es muy escasa, posiblemente debido a las inherentes dificultades para extraerlos de sus conchas. En este trabajo se documenta el 1 ) crecimiento relativo, dimorfismo sexual y el nivel de asimetría de las quelas del cangrejo ermitaño Coenobita clypeatus (Fabricius, 1787) recolectados en una isla coralina del Parque Nacional Arrecife Alacranes, sur del Golfo de México, durante diciembre de 2009 y septiembre de 2010. Los especímenes examinados fueron anestesiados con una solución de aceite de clavo para evitar la mortalidad innecesaria de cangrejos. Un total de 387 individuos se midieron en seis variables externas: largo y ancho del cefalotórax y largo y ancho de ambas quelas. Tomando la longitud del cefalotórax como la dimensión de referencia, el resto de las medidas se ajustó a una función de tipo potencial para examinar el grado de alometría en el crecimiento y hacer comparaciones entre los sexos. Para cada sexo, se calculó un índice de asimetría (AI) a fin de determinar el grado de heterogeneidad entre las quelas...