Family Isididae (Bamboo corals)

Bamboo corals are colonial octocorals characterized by an internal skeleton that alternates white internodes comprised of solidified calcite crystals with black or brown joints or nodes of nearly pure proteinaceous material (lacking sclerites).

The family was erected in 1812 by J.V.F. Lamouroux for the genera Isis and Melithaea (now classified in the Melithaeidae Gray, 1870, which also have proteinaceous nodes). There have been many revisions of the family and subfamilies since that time (see Grant [1976] and Alderslade [1998] for discussions of the history of Isididae classification), but no comprehensive work on the family since the monographs of Kukenthal (1919, 1924). The most recent systematic treatment is that of Alderslade (1998), who thoroughly revised the subfamilies Mopseinae and Circinisidinae.

A white skeleton and two dark-colored nodes (lower center and upper left) can be seen through a thin layer of tissue in this in situ close-up photo taken at 1889 meters depth. This species belongs to the subfamily Keratoisidinae, and the branches arising from the nodes would classify it in the genus Isidella, given current classification schemes.

Image copyright of the Deep Atlantic Stepping Stones Research Team; IFE-URI; and NOAA