Ten species of sea anemones (Anthozoa: Actiniaria) are documented in the Mexican Caribbean based on observations andcollections in 11 coral reef localities during 2006–2011; three of them are new records for Mexico. These species belongto families Actiniidae, Aiptasiidae, Aliciidae, Boloceroididae, Phymanthidae, and Stichodactylidae. Although these do notrepresent all species reported in the Mexican Caribbean, these are the most abundant and conspicuous. This work represents the first inventory of sea anemones of the Mexican Caribbean.

Seven sea anemone species from coral reefs in the southern Gulf of Mexico are taxonomically diagnosed and images from living specimens including external and in

This study compiles the diversity of sea anemones in different shallow habitats (i.e. rocky shores, coral reefs, mangroves and sandy bottoms) in several locations of Venezuela, including the most important marine reserves of Venezuela: Morrocoy National Park, Mochima National Park, Archipiélago de Los Roques National Park, Laguna de La Restinga National Park, Isla de Cubagua, and Chichiriviche de la Costa. Twenty-six species of sea anemones sensu lato were documented, from which only two actiniarian species are newly recorded in Venezuela. In addition, specimens of the scientific collection of the Museo Oceanológico Hermano Benigno Román, of Isla de Margarita, Venezuela, were examined and its taxonomic status updated. The diversity of sea anemones in Venezuela is updated to 44 species. An illustrated guide of living specimens and short descriptions of the external anatomy of the specimens is included to facilitate sea anemone species identification in the field and to provide a base line for ecological studies that require accurate identification to species level.

The shallow water sea anemone Phymanthus crucifer exhibits three distinct morphotypes, characterized by the presence or absence of protuberances on the marginal tentacles, as well as intermediate forms. The taxonomic status of the different morphotypes and the diagnostic value of protuberances on the tentacles have been debated for this species and the family Phymanthidae. We analysed the external and internal anatomy, cnidae and three mitochondrial molecular markers for representatives of each of the three morphotypes. In addition, we address the putative monophyly of the family Phymanthidae based on molecular data. With the exception of the protuberances, our morphological and molecular results show no differences among the three morphotypes; thus, we consider this feature to be intraspecific variability within P. crucifer. Furthermore, molecular data reveal that the family Phymanthidae is not monophyletic. In addition, we discuss several diagnostic morphological features of the family Phymanthidae.

The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (Na_V1.7), voltage-gated calcium channel (Ca_V2.2), the A-type transient outward (I_A) and delayed rectifier (I_DR) currents of K_V channels of the superior cervical ganglion (SCG) neurons of the rat. These results showed that the venom reversibly delays the inactivation process of voltage-gated sodium channels and inhibits voltage-gated calcium and potassium channels in this mammalian model. The compounds responsible for these effects seem to be low molecular weight peptides. Together, these results provide evidence for the potential use of zoanthids as a novel source of cnidarian toxins active on voltage-gated ion channels.