New records of sponges of the genera Petrosia and Xestospongia (Demospongiae: Haplosclerida: petrosiidae) from the Colombian Caribbean

Sponges (Porifera) are important constituents of littoral habitats in the Caribbean Sea. The knowledge of their biodiversity is fundamental to carry out ecological, managerial and utilitarian research. Their taxonomy is complex, but in the Caribbean in general, and in Colombia in particular, there are important advances. With this work, some sponge species of the genera Petrosia and Xestospongia are recorded and described for the first time from the Colombian Caribbean. Petrosia (Strongylophora) davilai, Xestospongia arenosa, Xestospongia deweerdtae and Xestospongia purpurea are described and illustrated. The number of records of Petrosia and Xestospongia for the Colombian Caribbean are now three and four species, respectively. In all species, the specimens from continental localities had larger spicule sizes than those from insular localities, apparently owing to a greater availability of dissolved silicon in the former. The existence in Xestospongia deweerdtae of free-living and Plakortis associated lifestyles was documented for new areas of the Caribbean