Towards a revision of the bamboo corals (Octocorallia): Part 4, delineating the family Keratoisididae.

The systematics of bamboo corals of the Family Keratoisididae are evaluated using both DNA sequences and morphological data. Sequence data were obtained from 398 specimens, from which 77 unique haplotypes representing the mtMutS and 18S gene regions were identified. These were aligned with sequences downloaded from GenBank from an additional 12 keratoisids and 6 octocoral outgroups. Phylogenetic analyses recovered seven well-supported major clades, the most recently derived of which consists of several subclades. Each clade and subclade can be characterized by a suite of morphological characters that include axis construction, branching pattern, polyp form, and sclerite type and arrangement. This analysis also shows that keratoisid genera described >100 years ago are paraphyletic and need revision and that a large number of new genera will need to be described.

Toward a revision of the bamboo corals: Part 3, deconstructing the Family Isididae.

Bamboo corals are distinguished from most other octocorals by an articulated skeleton. The nodes are proteinaceous and sclerite-free while the internodes are composed of non-scleritic calcium carbonate. This articulation of the skeleton was thought to be unique and a strong synapomorphy for the family Isididae. Our phylogeny, based on the amplification of mtMutS and 18S, shows an articulating skeleton with sclerite-free nodes has arisen independently at least five times during the evolutionary history of Octocorallia rather than being a synapomorphy characteristic of a monophyletic bamboo coral clade. The family Isididae is currently composed of four subfamilies (Circinisidinae, Isidinae, Keratoisidinae, and Mopseinae). Not only is the family polyphyletic, but our genetic analyses suggest also the subfamily Isidinae is polyphyletic based on current taxonomic classifications, and Mopseinae is not monophyletic. The type, Isis, is found outside of the well-supported Calcaxonia Pennatulacea clade where the other members of Isididae cluster. The current classification of the family Isididae does not reflect the evolutionary history of an articulated skeleton. To better reflect the evolutionary history of these taxa we propose that three of the four the subfamilies, the genus Isidoides, and genera within the subfamily Isidinae, be elevated to family level to produce a classification with five families with a bamboo-like skeleton: Chelidonisididae, Isididae, Isidoidae, Keratoisididae, and Mopseidae.