There are a great number of Protopalythoa species, but few of them have been classified.
Sea Mat, Button Polyps, Zoanthids.
Captive Care Notes:
These soft corals multiply rapidly under strong lighting and can overgrow other corals without adequate defense mechanisms. Protopalythoa also do well in lower lighting conditions, but will not multiply as rapidly. Medium to strong water current seems to help provide them with food as well as flush them of rejected material.
While most of these corals are brown to dark brown in color, a fair number of them contain elements in their tentacle tips, which fluoresces beautifully under actinic blue lighting.
Some of these Zoanthids feed on large food items, rapidly enclosing and swallowing the item, in a manner similar to that of many anemones. In an aquarium, they will consume just about whatever falls on them (uneaten foods, detritus), with the rejected food being washed away by water current.
See "What Do I Feed My Corals?" for more feeding information.
Palythoa and Protopalythoa species produce a chemical called palytoxin, which is a potent toxin and can be deadly to humans. Some indigenous Pacific tribes have used this neuromuscular toxin on spear tips to paralyze animals and their enemies.