column spacer Diversity of reef organisms
A healthy reef supports a rich diversity of organisms.  CLICK ON a "hot" button to see some examples of Caribbean reef plants and animals. Throughout the VIRTUAL DIVE we’ll see these and many other reef-dwellers and will study what they do, how they behave, and how they interact.  hot buttons for diversity section of BIOLOGY OF CARIBBEAN CORAL REEFS website diversity of corals diversity of gorgonians diversity of sponges diversity of worms diversity of molluscs diversity of crustaceans diversity of echinoderms diversity of tunicates diversity of turtles diversity of fishes diversity of sharks/mammals
icon for mollusc-diversity section of BIOLOGY OF CARIBBEAN CORAL REEFS website


Molluscs seen commonly on a Caribbean SCUBA-dive include conchs and other snails, octopuses and squids and, more often during night dives, nudibranchs.

seahorse "dive leader" in BIOLOGY OF CARIBBEAN CORAL REEFS website photograph of the track of a conch taken from a video

"Hmmm, who could be making this track?  Oh, a conch!  Not many molluscs are out in the daytime, but I guess conchs are too big to hide away. Other molluscs, like octopuses and nudibranchs, are best seen on a night dive" - Little Cayman 2003

NOTE a queen conch Strombus gigas

  Here are some representative
Caribbean molluscs:
photograph of sea hare Aplysia dactylomela
Spotted sea hares Aplysia dactylomela usually come out from hiding places in late afternoon to begin nighttime foraging for algal foods and searching for copulatory partners 0.5X
Long-horn nudibranchs Facelina sp. Special projections on the head called rhinophores are used for long-distance perception of prey and danger, while the tentacles or “long horns” at the front allow close-up touch and chemical perception of food 2X. Photograph courtesy Ann Dupont, Florida photograph of a flamingo-tongue shell Cyphoma gibbosum
photograph of nudibranch Facelina sp. courtesy Ann Dupont, Florida
Flamingo-tongue shell Cyphoma gibbosum crawling on a fan gorgonian on which
it feeds. The colorful mantle can be
withdrawn to leave the shell bare 3X
seahorse dive-leader in BIOLOGY OF CARIBBEAN CORAL REEFS website photograph of an octopus in its den taken from a video

There's not much action in a video of an octopus in its den...maybe things start happening after dusk. Still, you can see the siphon on the left ventilating, and the eyes are unusual in that they seem to have a more forward field of view. Most octopuses look at you from one side or the other. The animal is upside-down with its anteriormost arms wrapped around the borders of its hole - St. Maarten,

NOTE Octopus sp.


photograph of squids Sepioteuthis sepioidea courtesy Ann Dupont, Florida
Reef squids Sepioteuthis sepioidea locomote by paddling or jet-propulsing 0.05X. Photo courtesy Ann Dupont, FL
photograph of conch Strombus
Head of conch Strombus sp. showing eyestalks and tentacles. The snail is facing down and to the right 1X
photograph of file clam Lima scabra
File clams Lima scabra can swim by clapping their shells together. Lift is generated by the tentacle mass 0.5X
seahorse dive-leader in BIOLOGY OF CARIBBEAN CORAL REEFS website photograph of limestone rock with chitons and snails at the back part of the reef

"We’re a little out of our depth here, not to make a pun, but...let’s not forget the shore molluscs, like bleeding-tooth shells and chitons. They feed on algal scum and diatoms that they scrape off the rock" - Cayman Islands 2003

NOTE Nerita sp.

NOTE Acanthopleura granulata


Chitons and snails are fairly common on most Caribbean islands both intertidally and subtidally. However, because of their inconspicuousness and habitation of shallow-water habitats (chitons), and nocturnal habits (snails), they are not commonly noticed by SCUBA-divers.

NOTE collections of chitons in Barbados reveal 17 species living in low intertidal and subtidal regions. Most are small in size and inconspicuous in the bottom algal fuzz. Ferreira 1985 Bull Mar Sci 36: 189.

photo composite of intertidal molluscs in the back-reef area