Phylogenetics and taxonomy of the scleractinian coral family Euphylliidae

<p>The family Euphylliidae consists of reef-building zooxanthellate scleractinian corals distributed across the Indo-Pacific. Seven extant genera comprising a total of 22 valid species are currently recognised. Recent studies have re-organised the taxonomy of the family at the genus level based on molecular and morphological data, including a comprehensive revision of <em>Euphyllia</em> and the resurrection of <em>Fimbriaphyllia</em>. Here, three mitochondrial loci (COI, 12S rRNA, and 16S rRNA) were sequenced and morphological examinations were conducted at three scales (macro/micromorphology and microstructure of the skeleton, and polyp morphology) to study the phylogeny and taxonomy of Euphylliidae. We analysed a total of 11 valid species collected from seven Indo-Pacific localities. The monotypic genus <em>Coeloseris</em>, currently in Agariciidae, was also investigated since previous molecular data suggested a close relationship with the Euphylliidae. Molecular and morphological phylogenetic trees were broadly concordant in the definition of genus-level clades. All analysed genera, i.e., <em>Ctenella</em>, <em>Euphyllia</em>, <em>Fimbriaphyllia</em>, <em>Galaxea</em>, and <em>Gyrosmilia</em>, were reciprocally monophyletic based on molecular results. <em>Coeloseris</em> was nested within the family and, therefore, is formally moved into Euphylliidae. Updated morphological diagnoses are provided for each investigated genus. This study further demonstrated that a phylogenetic classification of scleractinian corals can be achieved by applying a combined morpho-molecular approach. Finally, we encourage phylogenetic and taxonomic studies of the euphylliid taxa not yet analysed molecularly, such as the monotypic genera <em>Montigyra</em> and <em>Simplastrea</em>. </p>