A review of carnivorous sponges (Porifera: Cladorhizidae) from the Boreal North Atlantic and Arctic

Abstract

Family Cladorhizidae, comprising the carnivorous sponges, represents a unique innovation within the phylum Porifera. Rather than filter feeding, carnivorous sponges have developed the ability to passively capture small invertebrates such as crustaceans using filaments or other appendages, coupled with an adhesive surface and the ability of sponge cells to migrate to and envelop prey items. Cladorhizids are most commonly deep-sea species and are found worldwide, with around 150 species currently described. The boreal Atlantic and neighbouring Arctic areas have a species-rich cladorhizid fauna, including many of the first cladorhizids described from early marine biological investigations. While a number of records exist for parts of these areas, other areas, such as the North-west Atlantic, are less well known, and species descriptions are scattered and in many cases lacking necessary information. Using a large set of specimens from newly collected material and multiple museum collections, and integrating this with previously published records from the area, we provide an overview of the cladorhizid fauna of the boreal Atlantic and adjoining Arctic Oceans. In all, we provide updated descriptions of 25 species, of which four, Asbestopluma (Asbestopluma) ruetzleri sp. nov., Cladorhiza kenchingtonae sp. nov., Lycopodina novangliae sp. nov. and L. tendali sp. nov., are previously undescribed. We also provide an overview of the known distribution and depth ranges of each species as well as a key for identification to species level. Finally, we provide some general discussion on the boreo-Atlantic and Arctic cladorhizid fauna and its relationship to neighbouring areas.