REASSESSING EVOLUTIONARY RELATIONSHIPS OF SCLERACTINIAN CORALS

The widely accepted family tree of Scleractinia published by Wells, ba sed on a combination of morphological coral taxonomy and the fossil re cord, has recently been revised by Veron. It is now possible to test t he validity of some of the conclusions reached by these and other auth ors by the use of molecular techniques. This paper reviews the results to date. Studies of ribosomal DNA have shown that the Scleractinia ar e monophyletic, i.e. derived from the same ancestral taxon. Extensions of this same data set now indicate that the Poritidae and Dendrophyll iidae, with their fossil antecedents, may each warrant separate subord er status. They further suggest (a) that the Suborder Faviina (faviids , mussids and their allies) should probably be retained as a monophyle tic group and (b) that Wells' original account of the isolated positio n of the Pocilloporidae and Astrocoeniidae is correct. These conclusio ns all accord with Veron's family tree. However, the Fungiina, even af ter removal of the Poritidae, are unlikely to be a monophyletic group at suborder level. The molecular data further show that externally obs ervable morphological characters used in the taxonomy of extant corals distinguish families more reliably than do internal micro-skeletal ch aracters frequently used in coral palaeontology.