Abstract.-An updated checklist of the marine invasive amphipod species from Mexico is documented. This list includes 11 species, belonging to the suborders Gammaridea and Corophiidea, and grouped in five families and six genera. Information about distribution, habitat, natural history, and dispersal mechanisms was added, according to the Sistema Nacional de Información sobre Biodiversidad and Análisis de Riesgo. The species Ampelisca abdita, A.burkei, A. schellenbergi, Melita nitida, Colomastix irciniae, C. tridentata, Ampithoe longimana, A. pollex, Apocorophium acutum, Monocorophium acherusicum, and M. insidiosum, were characterized as marine invasive species from Mexico.

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Abstract.-The brown shrimp (Penaeus aztecus) fishery is the most important in the Gulf of Mexico. This fishery takes non-target species or by-catch fauna, mainly teleost fishes, which are incidentally captured. Some of the by-catch species has commercial use and the rest of them are discarded. Therefore, it is important to describe the composition of the discarded fauna, to determine the impacts under the ecosystem approach. Discarding catch of shrimp trawls carried out in 2013 on the continental shelf off the State of Veracruz in different depth intervals (22-46 and > 46 m) was analyzed. For each trawl, the shrimp catch, the commercial by-catch and the discarding were recorded and the catch ratios respect to shrimp, were obtained. A discard sample was taken and the species were identified, the total length was taken and the ecological parameters were calculated. The non-parametric multiple dimensional scaling test was performed. A total of 7,178 fishes were collected from 34 families, 46 genera and 51 species. The ratio of commercial species by-catch: shrimp and discard: shrimp was 15.41:1 and 40:1 kg, respectively. The species with high relative dominance were Citharichthys macrops, Synodus foetens, Diplectrum bivittatum, Rhomboplites aurorubens and Upeneus parvus. The species with greater importance index were C. macrops, S. foetens, and D. bivittatum. The 43.14% of the discarded species are used as food and 7.84% as bait. The maximum diversity (H´) was 3.76 bits ind -1 and the trophic level was 4.31. The study of discard composition is a basis to assess the impact generated by the shrimp trawlers and provides guidelines for identify changes in the community structure. Key words: Discard, fishes, shrimp, Alvarado, VeracruzResumen.-La pesquería del camarón café Penaeus aztecus es la más importante en el Golfo de México. En esta pesquería se capturan de manera incidental especies no objetivo compuestas mayormente por peces teleósteos. Es importante describir la composición del descarte, para determinar el impacto de los arrastres camaroneros bajo un enfoque ecosistémico. Se analizó la captura de descarte de arrastres camaroneros realizados en 2013 en la plataforma continental del Estado de Veracruz en 22-46 y >46 m de profundidad. Para cada arrastre se registró la captura de camarón, fauna de acompañamiento comercial, descarte y fauna de acompañamiento. Se tomó una muestra del descarte, se identificaron las especies y se calcularon los parámetros ecológicos de la muestra. Se realizó una prueba de escalamiento dimensional múltiple no paramétrica. De 87 lances de pesca, se analizaron 7.178 organismos correspondientes a 34 familias, 46 géneros y 51 especies. Las especies con mayor dominancia relativa y mayor valor del índice de importancia fueron: Citharichthys macrops, Synodus foetens, Diplectrum bivittatum, Rhomboplites aurorubens y Upeneus parvus. Un alto porcentaje de las especies de descarte (43,14%) presentan uso potencial de alimento y 7,84% carnada. En promedio, la relación Fauna de Acompañamiento Comercia...

Resumen. Se analizaron la biodiversidad y los patrones de abundancia y distribución de los macrocrustáceos incrustantes, así como los registros nuevos y las ampliaciones de su ámbito geográfico. Fueron geoposicionados 6 sitios de muestreo en el parque arrecifal tomando en consideración la distancia de la costa, la geomorfología del ambiente arrecifal y la influencia de los contaminantes. En cada sitio se fijó una estructura de PVC con 6 placas artificiales entre los 8 y los 10 m de profundidad para la recolección de los macrocrustáceos incrustantes. Fueron identificados 8 161 organismos pertenecientes a 5 órdenes, 19 familias y 26 especies. De acuerdo con los valores de abundancia específica, dominaron el balano Amphibalanus amphitrite, seguido del tanaidáceo Leptochelia forresti y los anfípodos Ampithoe ramondi, Ampithoe sp. y Ericthonius brasiliensis. En este estudio se reconocieron 3 registros nuevos y 7 ampliaciones del ámbito geográfico. Finalmente, se comprobó la presencia de 2 grupos de macrocrustáceos, uno ubicado en el grupo norte y otro en el grupo sur del sistema arrecifal. Palabras clave: balanos, peracáridos, decápodos, ambiente arrecifal, suroeste del golfo de México.

Four new Gulf of Mexico records and nine geographic range extensions of peracarid crustaceans within the Gulf are presented for the southwestern Gulf of Mexico. The new records were obtained from plankton samples collected in the inlets of three Mexican coastal lagoons: Río Soto la Marina, Tamaulipas; Camaronera Lagoon, Veracruz and Términos Lagoon, Campeche. The new records include seven amphipod species (Caprella penantis, Gammaropsis atlantica, Monocorophium insidiosum, Hartmanodes nyei, Metaharpinia floridana, Westwoodilla sp., Parametopella texensis), one cumacean (Cyclaspis sp.) and five isopods (Excorallana berbicensis, Anilocra abudefdufi, Sphaeroma walkeri, Armadilloniscus sp., Erichsonella attenuata).

The objective of this study was to describe the morphology of Clibanarius antillensis Stimpson, 1859 megalopae collected in the vicinity of Isla Sacrificios, Mexico, and compare it to previous descriptions originated from Brazilian and Panamanian specimens raised in laboratory conditions. We found four meristic differences between the Brazilian and the Panamanian and Mexican populations with the Brazilian population: the outer flagellum of antennule in the Panamanian and Mexican populations has more aesthetascs on the second, third, and fourth segments of the outer flagellum (0, 6, 5, 3, 0) than the Brazilian population (0, 4, 4, 2, 0); the maxilla has more setae on the scaphognathite in the Brazilian specimens (70) than in the Mexican and Panamanian specimens (49-62); the crista dentata of the third maxilliped is formed by only three denticles in the Brazilian specimens, while 4 or 6 denticles form the same structure in the Panamanian and Mexican populations; there are fewer number of setae on the endopod of the uropod in the Brazilian population. The differences may be explained by intraspecific variation.

A new species of Leptostraca, Nebalia villalobosi, is described from the Veracruz Coral Reef System, SW Gulf of Mexico. The new species was found associated with the sponge Ircinia fistularis (Demospongiae) from the Blanquilla reef at a depth of 12 m. It differs from the closely related species N. longicornis and N. lagartensis in the form of the eyes and rostrum, the number of articles in the antennular and antennal flagella, the inner border of article 3 on the mandible palp, the length of the exopod of maxilla 2, the rounded denticles on pleonite 6, the enlarged tip on pleopod 5, and the caudal furcae being slightly longer than the telson and pleonite 7 combined. This is the first record of a leptostracan associated with the sponge Ircinia fistularis.

Se presenta una lista de los isópodos bentónicos asociados al Área Natural Protegida Arrecife Tuxpan-Lobos, México. Se realizaron muestreos en 11 sitios, entre 5 y 25 m de profundidad, en los meses de junio y julio de 2011. Fueron identificados 1,159 organismos pertenecientes a los subórdenes Asellota Latreille, 1802; Cymothoida Wägele, 1989; Limnoriidea Poore, 2002 y Sphaeromatidea Wägele, 1989; 5 superfamilias, 13 familias, 20 géneros y 31 especies. En este estudio se documentan 10 registros nuevos de isópodos para el Golfo de México: Carpias bermudensis, Joeropsis personatus, Hansenium spathulicarpus, Anthomuda affinis, Mesanthura bivittata, Pendanthura hendleri, Natatolana gracilis, Excorallana oculata, Excorallana quadricornis y Limnoria insulte, así como 16 ampliaciones del ámbito geográfico para esta fauna de crustáceos.