Urn ascidians

Scientific name : Didemnidi spp.

Many unidentified didemnids are observed in North Sulawesi seas. Species photographed in this page share urn-like colonial organization, with oral siphons opening at different levels around a common cloacal siphon.
Urns can stand alone or be grouped together. Sometimes colour is very brilliant.
Many Didemnid species are similar between them. All can be identified by the urn-shaped colony and by the oral siphons opening at all levels around a common cloaca.
At a first glance, confusion is possible with an encrusting sponge: putting a hand close, gently, if siphons close this must be an ascidian (sponges can not close their pores).

Associated organisms
Many didemnids live in association with other filter feeders, like solitary ascidians, sponges, hard corals.