Meeting Abstract
Corals are vital to many marine environments that depend on their diversity to sustain other marine organisms. Of the coral classes, Octocorallia is the most diverse, housing over half of all coral species diversity, but little is known of their phylogenetic relationships. Our objective for this study was to build a phylogeny for Pacific Basin octocoral families to understand their evolutionary relations. We sampled octocorals found in the deep-sea California waters and Pacific coral reefs as these regions contain a high abundance of octocoral species. We first surveyed the morphological diversity of sclerites, the skeletal scale-like components of corals, through scanning electron microscopy (SEM). We then used Sanger methods to sequence the ND6, ND2, and msh1 genes of 16 octocorals from a range of different families. Sequences were then aligned and concatenated within Mesquite and then used to build Bayesian and maximum likelihood trees. The topography and bootstrap values of these trees strongly suggest the order Pennatulacea and family Ellisellidae, which is placed in the suborder Calcaxonia, are sister taxa. We conclude that the designation of Pennatulacea as a separate order does not reflect evolutionary history and that the pennatulacean axis was likely derived from a calcaxonian ancestor. Future directions would include the addition of more samples from Ellisellidae and Pennatulacea to determine whether the support for our hypothesis remains strong. Our analysis would also benefit from a thorough comparison of the morphology of Pennatulacea and Ellisellidae. On a broader scale, sampling more species from other octocoral groups (scleraxonians, alcyoniinans, and holaxonians) could result in findings of other paraphyletic taxa within Octocorallia.
