''Amphimedon compressa'', the erect rope sponge, red tree sponge, red tubular sponge, or red sponge is a

demosponge Demosponges or common sponges are sponges of the class Demospongiae (from + ), the most diverse group in the phylum Porifera which include greater than 90% of all extant sponges with nearly 8,800 species A species () is often de ...

found in southern

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

, the

Caribbean Sea The Caribbean Sea is a sea of the Atlantic Ocean, North Atlantic Ocean in the tropics of the Western Hemisphere, located south of the Gulf of Mexico and southwest of the Sargasso Sea. It is bounded by the Greater Antilles to the north from Cuba ...

, and the

Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. ...

. It can be deep red, orange, brown, or black.

Taxonomy

The erect rope sponge used to be classified as ''Haliclona rubens'', but this was determined to be a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''Haliclona compressa''. This name, however, is no longer accepted, and the World Porifera Database lists this species as ''Amphimedon compressa'' – Duchassaing & Michelotti, 1864.

Description

''Amphimedon compressa'' can grow to a length of and a diameter of , but it is usually smaller in shallow water. The tree-like curved branches grow from a basal encrusting mass, but very occasionally this sponge grows as a small, unbranched, flattened hemisphere. Many small osculi are found on the branches. It is usually a dull dark red, but the colour varies and it is sometimes black, dark brown, greyish-brown, bright red, or orange. In dark positions under overhangs, it grows in mats and its colour is weak.

Distribution

The erect rope sponge grows as part of the coral reef community. It occurs in Florida, the Caribbean Sea, and the Bahamas at depths to about . It occurs on the crests and sides of the reef growing on rock, and on vertical surfaces, it protrudes sideways.

Biology

The erect rope sponge feeds on plankton and tiny organic particles suspended in the water. To do this, the sponge draws in water through small pores called ostia, filters out particles in the

choanocyte Choanocytes (also known as "collar cells") are cells that line the interior of asconoid, syconoid and leuconoid body types of sponges that contain a central flagellum, or ''cilium,'' surrounded by a collar of microvilli which are connected by ...

tissue, then moves the water through the

spongocoel A spongocoel (), also called paragaster (or paragastric cavity), is the large, central cavity of sponges. Water enters the spongocoel through hundreds of tiny pores ( ostia) and exits through the larger opening ( osculum). Depending on the body pl ...

or central cavity before pumping the water out through the osculi.

Ecology

''Amphimedon compressa'' is part of a sponge community in a belt at depths between off the Cayman Islands, and often grows out horizontally from rock faces. It often has the sponge brittle star (''

Ophiothrix suensoni ''Ophiothrix suensoni'', Suenson's brittle star or the sponge brittle star, is a species of marine invertebrate in the Order (biology), order Ophiurida. It is found in the Caribbean Sea and Gulf of Mexico. It is included in the subgenus ''Acantho ...

'') living on its surface. Sponges are often eaten by

sea stars A sea is a large body of salt water. There are particular seas and the sea. The sea commonly refers to the ocean, the interconnected body of seawaters that spans most of Earth. Particular seas are either marginal seas, second-order section ...

, but the red tree sponge contains certain

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

s which deter feeding by the common Caribbean starfish ''

Echinaster echinophorus The orange knobby star, ''Echinaster echinophorus'', is a species of sea star found in the Caribbean Sea and along the Atlantic coast of South America. Description It is a small species with a diameter of up to . It has a small central disc and ...

''.

References

{{Taxonbar, from=Q2036623 Chalinidae Sponges of the Atlantic Ocean Sponges described in 1864