are members of the family Clionaidae
. They are efficient excavators of calcareous materials including corals and shells. Boring (burrowing) sponges create a canal system by chemically etching out coral or shell material for shelter and during the process simultaneously create sediment (Holmes 2000). Cliona
spp. are not predators and do not derive any nutrients from their host, however they are competitors for space on appropriate substrata (Lopez-Victoria and Zea 2005). This is a highly adaptable genus of sponge that not only excavates, but is also capable of encrusting the surface and smothering the host. There is evidence of Cliona
spp. in the fossil record as early as the Lower Cambrian (Ward and Risk 1977). Boring sponges range in color from yellow to dark-brown to black brown with a yellow oscula (Leidy 1889, Zea and Weil 2003, Vacelet et al. 2008). Many species are host to symbiotic zooxanthellae (Mariani et al. 2000, Vacelet et al. 2008).