Lucanicum concatenatum is a chain-forming araphid pennate, assigned to Cyclophorales: Cyclophoraceae on the basis of morphological characters and DNA sequences, resembling Neosynedra, but with platelike plastids and striae mostly undivided by vimines. So far it has only been found growing on blue coral, Heliopora coerulea, but we do not suggest that it is restricted to this habitat. Its phylogenetic position, near Cyclophora, Florella and Astrosyne, requires amendment of the diagnosis of Cyclophorales, which included characters unique to C. tenuis, the only species in the order at that time. The question of the scope and description of the Cyclophoraceae remains unresolved.
