This year a very peculiar solitary stony coral called Dactylotrochus was described from small colonies collected from the deep sea. What makes Dactylotrochus cervicornis special is that unlike the large meaty solitary deep sea corals which we are familiar with in the Flabellidae and Caryophyllidae families, the new species is from the family Agariciidae. What this means for Dactylotrochus is that it is more closely related to Pavona and Leptoseris than the fleshy stony corals we usually think of coming from the ocean abyss.
Like the newly discovered Leptoseris troglodyta, Dactylotrochus is also non-photosynthetic since it lives beyond the direct reach of the sun at depths of 230 to 2800 feet! Dactylotrochus was originally described as Tridacophyllia cervicornis way back in 1881 but just this year the coral was re-evaluated with genetics and morphology to determine its close relation to more familiar shallow-water stony corals that we know and love.
The transfer of Dactylotrochus into the family of Pavona, Leptoseris and Agaricia sheds some light on the potential evolutionary path that members of this family have taken, perhaps beginning as azooxanthellate corals and then specializing for the low-light reef niches which often requires some dependence on feeding on particulate foods. Although we only have skeleton pictures to go from the unique branching shape of Dactylotrochus borders on the astounding. Could you imagine if Dactylotrochus carried some of the genetics for coloration similar to Leptoseris and some specimens existed with green, orange or red pigmentation? So many cool corals, so little time.