New species of Zyzzya, Cornulella, Damiria, and Acheliderma (Porifera: Poecilosclerida), with a review of fistular genera of Iophonidae

New sponge species belonging to the closely related fistular genera Zyzzya, Cornulella, Damiria, and Acheliderma are described from reef habitats off the coasts of Colombia, Bonaire and Curaçao in the southern Caribbean. With very few exceptions these sponges are small to tiny specimens inhabiting crevices and other cryptic habitats; some may be excavating. For comparison both published and unpublished material belonging to these genera from other parts of the world was examined, and this yielded several nomenclatorial changes and a further three new species from the Indian Ocean. The new species are: Zyzzya invemar (Caribbean), Cornulella santamartae (Caribbean), C. tyro (Seychelles), C. amirantensis (Seychelles), Damiria leonorae (Caribbean), D. toxifera (Seychelles) and Acheliderma lisannae (Caribbean). All species belonging to these genera, as well as to the closely related Indo-Pacific genus Paracornulum, are briefly diagnosed. The genera and species of this group are found to be distributed over tropical and subtropical waters of all three oceans. The five genera were so far of controversial systematic allocation, although their close relationship with Cornulum was generally accepted. The recently revived family Iophonidae is demonstrated to be the likely assemblage for them. A brief survey of Iophonidae genera is presented and a preliminary phylogenetic analysis of the fistular genera is attempted. Although several parts of the phylogenetic relationships remain unsolved, it is nevertheless clear that in all genera the closest relatives are not found in adjacent areas, but are often disjunct.