Actinocyclus verrucosus at Kwajalein seems to prefer seaward reefs in channels and on the top of the reef slope, where it can occasionally be found under rocks feeding on a somewhat shiny brown sponge. It can occasionally be on lagoon reefs and pinnacles. Often it closely resembles the sponge and blends in very well. Hallaxa sp. e467 was also found on the same sponge, suggesting that species could be a smooth form of A. verrucosus. The one below was under a rock on a shallow lagoon reef on 20 May 2013.
It comes in a lighter colored form.
A specimen with an egg mass found under a rock on 29 June 2014.
The small specimen below was making a trail, grazing through a thin light gray sponge.
Created 15 December 2006
Updated 16 December 2021