Scolymia lacera

Lore & Background

Scolymia lacera is a coral with a single, solitary polyp and does not increase in size by budding as do colonial species of coral. It is a small species with a diameter of up to 6 centimetres. The radially-running ridges in the stony cup which it secretes can be seen through the fleshy body of the polyp. Its colour is variable and is usually some shade of greenish-brown. Scolymia lacera is very similar in appearance to Scolimia cubensis which occupies much the same range. The differences are mostly in the layout of the septa, the miniature ridges in the calcareous calyces in which the polyps sit. S. lacera tends to occupy better lit positions while S. cubensis is in less well lit locations. Where the two come in contact, S. lacera is more aggressive.

Scolymia lacera is found in the Caribbean Sea, the southern half of the Gulf of Mexico, the Bahamas and southern Florida. It grows on reefs, rocky outcrops and steep reef slopes at depths of between 15 and 80 metres. It contains single-celled symbiotic algae called zooxanthellae in its tissues. These are photosynthetic and use energy from the sun to produce organic compounds from which the coral also benefits. Much of its energy needs are supplied in this way but it also extends its ring of short tentacles to catch plankton, feeding mostly at night. Scolymia lacera is an aggressive coral that attacks neighbouring corals that might deprive it of light. It does this by extruding filaments several centimetres long from its mesenteries. When these come in contact with another coral they secrete enzymes that in the course of several hours digest its soft tissues. Smaller corals may be killed by this attack while larger individuals may have the part within reach stripped back to the skeleton.

Reader's Guide

Scolymia lacera is significant as a solitary, non-colonial stony coral that demonstrates aggressive competitive behavior for light access on reefs. Its method of attack—extruding digestive filaments from its mesenteries to digest the soft tissues of neighboring corals—is a notable adaptation in the family Mussidae. The species relies heavily on symbiotic zooxanthellae for energy, but also supplements its diet by nocturnal plankton capture. Its conservation status is critically endangered according to the IUCN Red List, with threats including a rise in sea temperature and consequent coral bleaching, increased severity of storms, ocean acidification, coral disease, and various human impacts. The species is distinguished from the similar Scolimia cubensis primarily by septal layout and a preference for better-lit positions, and where they meet, S. lacera is the more aggressive. Its restricted distribution in the Caribbean, Gulf of Mexico, Bahamas, Bermuda, and southern Florida, combined with its vulnerability to environmental stressors, underscores its precarious status.

Did You Know?

• Scolymia lacera is a solitary polyp and does not reproduce by budding like colonial corals.
• It attacks neighboring corals by extruding filaments that secrete enzymes to digest soft tissues.
• The species is listed as critically endangered on the IUCN Red List.
• It contains symbiotic zooxanthellae that provide much of its energy through photosynthesis.