Noumea decussata Risbec, 1928

Noumea decussata was relatively common at Enewetak Atoll and is occasionally found at Kwajalein. Just how common is hard to tell, because for some time I was mistakenly considering these to be the same as another species, Noumea simplex. Finally I started noticing that specimens with a certain pattern of color were always on this yellow sponge, while the other consistent pattern was always on a pink sponge. A closer look at the patterns and anatomy revealed them to be different species. Twenty-four specimens measured after I finally got them straightened out ranged from 6 to 18mm in length, and they were nearly always under dead coral and aluminum storm debris on lagoon interisland reefs at depths of 3 to 5 meters.

Burrowing through its prey sponge.

Three individuals clustered on a tiny patch of yellow sponge. They'll soon have to find some more food.

This species usually shows a midlateral bulge in the body. That's this specimen's egg mass over to the right.

Created 18 December 2005
Updated 20 December 2008