Porifera

Abstract

Poriferans (sponges) are sessile aquatic (largely marine) animals that are found in almost all benthic habitats. There are an estimated 15,000 species living today, although many have not been described (reviewed in Hooper and Van Soest 2002). The sponge body plan is amongst the simplest in the animal kingdom and lacks nerve and muscle cells and a centralised gut (reviewed in Simpson 1984; Ereskovsky 2010; Leys and Hill 2012). Their body plan and ecology, and thus their evolution, appear to be intimately associated with the diversity of microbial symbionts they harbour (reviewed in Hentschel et al. 2012; Thacker and Freeman 2012), as is the case with other metazoans. Show more