BILEWITCH , J.B.; COATES, K.A.*; Univ. of Toronto; Bermuda Biological Station for Research: A Morphometric Reanalysis of Gorgonian Sclerites: �Old Microscopy� Sheds New Light on Octocoral Phylogeny

Historically, taxonomic classifications of octocorals were based on morphology of sclerites without testing character homology in a phylogenetic framework. Recently, some inter- and intra- generic relationships have been elucidated with cladistic methods but the majority of octocoral relationships have not been examined in this way, despite the vast amount of sclerite descriptions and measurements accumulated over past decades. We have thus analyzed the shape and size distributions of sclerites in a number of holaxonian octocoral species from Bermuda and the Bahamas using discrete and morphometric distinctions of character states. Using digital images captured from a compound light microscope, we were able to reconstruct a cladogram that allows evaluation of common taxonomic indicators as well as the evolutionary relationships of octocorals, themselves. We found our morphology-based phylogeny inconsistent with historical taxonomy and identified several sclerites types and sizes useful in identification of species, genera, and families. Furthermore, we examined the variation in our continuous variables as an indicator of phylogeography by comparing mean sizes in Bahamian and Bermudian populations. Finally, we compared and combined our morphological characters to recent molecular data in both consensus and total evidence phylogenetic trees. Analyses combining both types of data appear more robust and implicate more useful characters for distinguishing the studied taxa. They also suggest a continuing need for morphological characters in an ever-increasing world of molecular phylogenetics.