''Cliona delitrix'' is a species of burrowing

demosponge Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include 76.2% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). They are sponges with a soft body that covers a har ...

belonging to the family Clionaidae. It is found in shallow water in the Caribbean Sea and the Gulf of Mexico.

Description

''Cliona delitrix'' is a burrowing sponge that is also encrusting. It usually grows on a massive coral, not only covering its surface but also burrowing into its interior, but is sometimes found on some other calcareous

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

such as a shell or a limestone rock. It does not normally grow on branching corals. It can grow to a diameter of up to a metre (yard) and has several large openings called osculi, wide, surrounded by projecting rims and many small raised papillae wide. The colour is usually red or dark orange.

Distribution and habitat

''Cliona delitrix'' is found in the Caribbean Sea and Gulf of Mexico at depths down to . Its range extends from Cuba and Mexico south to Venezuela and Brazil. It is abundant in some areas especially where there is organic pollution.

Biology

The main corals on which ''Cliona delitrix'' grows are ''

Siderastrea siderea ''Siderastrea siderea'', commonly known as massive starlet coral or round starlet coral, is a stony coral in the family Siderastreidae. It is found in shallow parts of the western Atlantic Ocean as solid boulder-shaped or domed structures. Desc ...

'', '' Diploria labyrinthiformis'' and ''

Montastraea cavernosa ''Montastraea'' is a genus of colonial stony coral found in the Caribbean seas. It is the only genus in the monotypic family Montastraeidae and contains a single species, ''Montastraea cavernosa'', known as great star coral. It forms into massiv ...

''. The sponge is a filter feeder, removing bacteria and other organic particles from the current of water sucked in through its many pores by the movement of flagella. There are channels and chambers inside the sponge and the water finds its way through them and exits through the osculi. The

zoanthid Zoanthids ( order Zoantharia also called Zoanthidea or Zoanthiniaria) are an order of cnidarians commonly found in coral reefs, the deep sea and many other marine environments around the world. These animals come in a variety of different coloniz ...

coral ''

Parazoanthus parasiticus ''Umimayanthus parasiticus'', commonly known as the sponge zoanthid, is a species of coral in the order Zoantharia which grows symbiotically on several species of sponge. It is found in shallow waters in the Caribbean Sea and the Gulf of Mexico. ...

'' is often found growing on the surface of this sponge. ''Cliona delitrix'' is a

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

. The male gametes are produced first and get swept out by the water current. If they are sucked into another sponge, fertilisation can take place. The larvae may be

brooded Egg incubation is the process by which an egg, of oviparous (egg-laying) animals, develops an embryo within the egg, after the egg's formation and ovipositional release. Egg incubation is done under favorable environmental conditions, pos ...

for a while inside the sponge but then leave through the osculi and become planktonic. They drift with the current before settling on the seabed. Each one then starts to grows over the surface of whatever it has landed on. It needs calcium to flourish and if it settles on something calcareous like a massive coral, it will secrete acid to dissolve it as well as continuing to grow over the surface. The interior of the coral may be riddled with holes filled with orange spongy material. The sponge kills the part of the coral close to its growing edge. It is an aggressive species and large corals may have the greater part of their surface covered while small individuals may be completely engulfed. When a massive coral is already dead, the sponge excavates the interior while it colonises the surface, but if encrusting algae are already established on the surface, the sponge's growth is slowed down. In a study off the coast of Colombia, the most favoured host for the sponge was the starlet coral (''Siderastrea siderea'') and between 6% and 9% of individuals of this species were affected. It is such an aggressive sponge that it is considered likely that, in areas where it is present, branching and foliose corals may come to out-number massive corals in the long term. When a colonised coral dies and crumbles, parts of the sponge in the excavated tunnels may break up and detached pieces may become established in a new location, a form of

asexual reproduction Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the fu ...

References

{{Taxonbar, from=Q2668040 Hadromerida Animals described in 1973