Atriolum robustum (Robust sea squirt)


The colonies are composed of several small urns often contiguous and elongated egg-shaped, each measuring at most 15 mm in height and connected by a encrusting common basis.
The body wall is perforated by a number of pore-like buccal siphons, each raised on a slight elevation, giving the zooid a pine cone-like appearance.
The tunic has a red pigment that is visible on the inside of the common atrial siphon and the level of oral openings.. This pigment is often masked by the presence of green algae symbiotic (Prochloron sp.) contained in the coat, giving a yellow-green color to the whole colony.


Not yet been assessed for the IUCN Red List.


Found in the tropical western and central Indo-Pacific, range extends from Madagascar to Australia and Papua New Guinea and includes Reunion, Mayotte and New Caledonia.
Depth range between 12 and 300 metres, on hard substrate.


Sexual reproduction involves sperm being drawn into the body cavity with the inflowing water current and eggs being fertilised internally.
The developing embryos are brooded at first.


Prey / Predation

Feeds on phytoplankton, zooplankton and detritus.
This animal is a filter microphagous and feed on small particles.
It generates a stream of water (by individual inhalant holes) to capture airborne particles.
Digested waste particles then exit through the big exhalant siphon.

Eaten by various predators including the Egyptian sea star (Gomophia egyptiaca) and the sea snail, (Gyrineum gyrinum).

Special features