*Sporal psephos*. A moiety (two paired species) of a sponge and a coral. Possibly a single chimeric organism.
1. Reefbuilding Reefbuilding on this world seems to be carried out by a range of sponge-coral pairings. In hard corals, the sponge has lost its ability to feed independently and provides a hard shell for the corals. In this organism, the relationship is reversed: the coral polyps grow a hard surface shell, while the sponges continue to pump water. Because the hard shell blocks the sponges' pores, they work in pairs, with one inhaling through its osculum and one exhaling.
2. Dome coral association Frequently found on the surface of the larger dome coral, blocking patches of its surface from receiving sunlight. This may be an opportunistic/parasitic relationship.
3. Confusing genetics Both coral polyps and sponge cells seem to carry the full genome of both organisms, blurring the definition of a species. It is unknown how a single organism can contain genomes for two biologically distinct species; the two cannot reproduce sexually to combine their genes.
Assessment: interesting data point.