Fifteen species of sea anemones (Cnidaria, Actiniaria) have been recorded so far in the Colombian Caribbean, comprising approximately 28% of the total number of known species in the Caribbean Sea. Most species recorded are associated with coral reef communities. However, in the region, no records of sea anemones are known from areas with high sedimentation conditions as is characteristic along the coastline of the Atlántico Department, in Colombia. In this area, organisms are exposed to a high degree of turbidity and sedimentation (~143.9x10 6 t year -1 ) as a result of their proximity to the Magdalena River mouth and the 26 micro-basins that fl ow along its coastline. Several observations and collections were made on soft bottoms, rocky, and artifi cial substrates in the sectors of Puerto Velero and Caño Dulce to determine the fauna that exist under these conditions. Four species of sea anemones were found belonging to the families Actiniidae and Aiptasiidae, and images from living specimens and cnidae are provided.Bunodosoma cavernatum and Exaiptasia diaphana are here recorded for the fi rst time from the Colombian Caribbean. An updated list of sea anemones in the Colombian Caribbean, now comprising 34 taxa (i.e., 21 species and 13 identifi ed at supra-specifi c levels), is provided.

Sea anemones have developed various strategies for interspecific interaction with other organisms and their own ability to obtain food, due to their coevolutionary history, ranging from mutualistic (e.g. clownfish, crustaceans, etc.) and symbiotic associations (zooxanthellae or zoochlorellae) to depredation (e.g. sea slug). This study aims to record some observations on feeding habits and interspecific interactions of Actinostella flosculifera (Le Sueur, 1817) in the locality of Pedra da Sereia in Vila Velha, Espírito Santo, Brazil, and to describe the hunting strategy of the sea slug Spurilla braziliana MacFarland, 1909 and the escape strategy of A. flosculifera. We found that the habitat of A. flosculifera is characterized by shallow pools ~10 cm deep at low tides, and this functions as a trap for many organisms and some biowaste (e.g. bones or fish drifting in from nearby populations) that fall into the oral disc. This is the first report of S. braziliana predating on A. flosculifera. We also report interspecific relationships between A. flosculifera with four species of crustaceans: Omalacantha bicornuta (Latreille, 1825), Menippe cf. nodifrons Stimpson, 1859, Alpheus cf. angulosus McClure, 2002, and Alpheus cf. carlae Anker, 2012.

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ResumenEl subfilo Medusozoa (clases Cubozoa, Hydrozoa y Scyphozoa) se caracteriza por un esquema corporal predominantemente medusoide. El subfilo agrupa organismos con características pelágicas, lo que en cierta medida ha dificultado su conocimiento y estudio. En el Caribe colombiano se han registrado 25 de las 130 especies presentes en el mar Caribe, pero se considera que aún debe ahondarse en el conocimiento en torno a su diversidad local y regional. En este trabajo se registró la composición de las especies de Medusozoa presentes en algunas localidades del departamento del Atlántico, con énfasis en el sector turístico de Puerto Velero. Los registros se obtuvieron entre agosto de 2016 y diciembre de 2017. Las muestras se recolectaron de diversas formas: manualmente, utilizando arrastres superficiales con una red rectangular (1 mm de apertura de malla), o durante actividades de pesca. Se observaron siete especies: una de Hydrozoa, una de Cubozoa y cinco de Scyphozoa. Aurelia aurita y Chrysaora sp. fueron las más frecuentes en el sector de Puerto Velero. Aunque la mayoría de las especies son de distribución amplia o cosmopolita y ocasionalmente llegan a las costas del Caribe colombiano, en el Atlántico solo se tenía registro de una de ellas, por lo que estas observaciones amplían la información sobre su diversidad y frecuencia de aparición en esta zona del país, lo cual es de importancia para gestión y conservación en los lugares que desarrollan actividades turísticas. © 2018. Acad. Colomb. Cienc. Ex. Fis. Nat. Palabras clave: Caribe colombiano; Zona turística; Medusas. Contribution to the knowledge on jellyfishes (Cnidaria: Medusozoa) in the department of Atlántico, Colombia AbstractThe Medusozoa subphylum (Cubozoa, Hydrozoa, and Scyphozoa classes) is characterized mainly by a medusoid body scheme. The subphylum groups together organisms with pelagic characteristics, which to some extent has hindered their knowledge and study. Twenty five of the 130 species found in the Caribbean Sea have been recorded for the Colombian Caribbean, but new efforts are required to understand their diversity at local and regional level. In this study we registered the composition of subphyla species in some localities of the department of Atlántico, with an emphasis in the Puerto Velero tourist area. We collected the material between August 2016 and December 2017. Samples were collected manually, using a rectangular surface net (1 mm mesh opening), or during fishing activities. We recorded seven species: One from the Hydrozoa subphylum, one from the Cubozoa, and five from the Scyphozoa. Among these, Aurelia aurita and Chrysaora sp. were the most frequent in the Puerto Velero area. Although most of these species are widely distributed or cosmopolitan, and occasionally reach the Colombian Caribbean coasts, only one of them was previously recorded in the department of Atlántico. This new register increases the knowledge regarding their diversity and frequency of occurrence in this area of the country, and it is of particular interest...

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