Field Guide to Venomous and Medically Important Invertebrates ...

Figure 244. Unidentified sea fan, Africa. Photo: Democratic Republic of Congo.
Corals
Corals are a diverse group of marine sessile coelenterates who secrete calcareous, rock-like
shelters that can occur in such densities as to create islands and atolls. The Great Barrier Reef of
Australia is composed of the calcareous limestone deposits of dead and living corals. Wherever
corals occur they can pose two potential threats to people. Many corals both dead and alive are
very sharp and can produce serious cuts to unprotected areas of the body. These types of corals
are especially dangerous in tropical regions of the Pacific Ocean. Precaution should be taken in
areas where these corals occur and signs posted on beaches warning of dangerous corals should
be taken seriously. The other type of dangerous corals produce stings when accidentally
contacted. Such stings feel like burns and generally produce reddened inflamed patches on the
skin where the contact occurred. Local anesthetic ointment is effective as a pain reliever, but
victims may require additional medical treatment in severe cases. One of the most common fire
corals distributed in warm oceans around the world is Millepora complanata.
Figure 245. Beach sign warning of sharp coral. Photo: Hawaiian Lifeguard Association.
Figure 246. Fire coral (Millepora complanata). Photo: Henderson State University.
Bryozoans
Bryozoans (Phylum Ectoprocta) are colonial animals found in both freshwater and marine
habitats. A single marine species, Alcyonidium gelatinosum (Family Alcyonidiidae), widely
distributed in both Atlantic and Pacific oceans, can produce irritating erythematous dermatitis
(Dogger’s Bank itch) when contacted. This species occurs commonly among European coastal