Phyllodesmium kabiranum from Malaysia

Dear Mike,
Thanks for the photos. When you see this colour form alongside its soft coral food you can see just how well camouflaged it is - the dark basal part of the cerata matching the brown trunk of the xeniid polyp, and the wrinkled whitish tip looking like the retracted tentacles of the polyp. As Phyllodesmium will normally be 'disturbing' soft-coral colonies when it is near it, it is better for Phyllodesmium, if it trying to be camouflaged, to look like a xeniid colony with retracted polyps, than one with expanded tentacles.

In the bottom right corner of the photo alongside you can see part of a well camouflaged Phyllodesmium alongside a soft-coral colony. Phyllodesmium kabiranum is reported to feed only on the genus Heteroxenia but it seems the only way that species of Heteroxenia differ from species of Xenia is the presence of autozoids in Heteroxenia. However autozoids are small non-tentaculate polyps which appear as small, slightly raised pores on the surface of the colony between the normal polyps, and some researchers report that they only appear at some times of the year. Which means from photos, and most field identifications, it is impossible to differentiate between the two genera.

Best wishes,
Bill Rudman