Spirastrella coccinea

Spirastrella coccinea is found in the Caribbean Sea, the Gulf of Mexico and the tropical western Atlantic Ocean as far south as Brazil. It grows on hard substrates, coral reefs and coral rubble at depths down to about 15 m (50 ft), and has been found in a submarine cave as well as among mangrove roots.^[2][3]

Being soft-bodied, sessile organisms that lack physical defences, sponges have developed chemical defences to protect them from predation. Many of these compounds are bioactive and are of interest in pharmaceutical research.^{[citation needed]} A novel mitotic inhibitor macrolide known as "Sprirastrellolide A" has been isolated from Spirastrella coccinea. The methyl ester of Sprirastrellolide A has the unusual biological property of causing cells to start dividing when they are at other stages of the cell cycle, before stopping them dividing partway through the process.^[4] Another macrolide, "Sprirastrellolide B", has also been isolated and its structure elucidated.^[5] Since then, five further macrolides, "Sprirastrellolide C to G" have been found in extracts of the sponge, their structures being elucidated by spectroscopic analysis and chemical means.^[6]