White Encrusting Zoanthid – Palythoa caribaeorum
The White Encrusting Zoanthid is a species in the order of the Zoantharia and thus belongs to the class of the Anthozoa. They are very toxic and should therefore not be touched under any circumstances. Palythoa caribaeorum was first described by Duchassaing & Michelotti in 1860.
Description, Anatomy & Characteristics
Palythoa caribaeorum has a circular shape. At the edge of the body disk are two rings with small tentacles. While the tentacles of the inner ring usually stand upright, they are flat on the outside.
Their colouring is light beige.
Single polyps reach up to 1.3cm in diameter, together they can take up several m² area.
Habitat & Distribution
The White Encrusting Zoanthid lives on rocky reefs with water movement up to 12m depth. Thereby it prefers coastal areas.
When scuba diving on the Canary Islands you can watch them from time to time. If you know the corresponding places, you can of course dive at them specifically.
It can also be found in the western Atlantic from the Bahamas via Florida, the Gulf of Mexico, the Caribbean, Brazil, to Puerto Rico. On http://www.naturalista.mx/ you will find a distribution map of Palythoa caribaeorum.
Biology, Feeding & Reproduction
Palythoa caribaeorum lives sessile in colonies. The biggest I’ve seen so far is about 10m².
Together with the White Encrusting Zoanthid you will find the Harlequin Crab.
They also feed on light and plankton.
White Encrusting Zoanthids can reproduce both sexually and asexually.
In Brazil, Cantherhines macrocerus, a species of the order of Tetraodontiformes, was observed to feed on the White Encrusting Zoanthids. I also found a report that the Hawksbill Turtle (Eretmochelys imbricata) is a predator, too.
Not much is known about the further biology of the White Encrusting Zoanthid. During night dives with blue light I could determine that they fluoresce.
Is it poisonous?
According to several sources, Palythoa are generally very toxic. However, on various aquaristic pages it is reported that no poisoning has occurred on contact. However, you should still be careful, as reasonable divers do. Allergic reactions are also possible.
The poison of Palythoa caribaeorum is also the subject of research, as it is thought to have healing effects.
Sources & Links
https://reefguide.org/ – Images of Palythoa caribaeorum