We present an integrative study with molecular phylogenetic reconstructions and morphological assessment across the three Ceriantharia families: Arachnactidae, Botrucnidiferidae and Cerianthidae. The Arachnactidae specimens (Isarachnanthus spp.) form a well-supported clade, whereas Cerianthidae and Botrucnidiferidae are not recovered as monophyletic. Consequently, the validity of the suborder Spirularia is questioned. Cerianthus was recovered as polyphyletic and Ceriantheomorphe may prove to be a junior synonym of Cerianthus. The taxonomic position of Cerianthus cf. mortenseni is also discussed. All specimens identified on morphology as belonging to Pachycerianthus are recovered as a clade. Further revision of taxa within Ceriantharia is necessary. Molecular phylogenetic analyses based on six mitochondrial or nuclear loci place Ceriantharia as sister to Hexacorallia s.s., but with no significant support relative to an alternative hypothesis that it is the sister taxon to Octocorallia. Further molecular sequence data and taxon sampling will be needed to resolve the position of Ceriantharia.
Bibliographical noteKAUST Repository Item: Exported on 2021-02-09
Acknowledgements: The authors acknowledge the Integrative Systems Biology Laboratory [King Abdullah University of Science and Technology (KAUST)] and Biosciences Core Laboratory (KAUST) for support and assistance. This research was undertaken in accordance with the policies and procedures of KAUST. Permissions relevant for KAUST to undertake the research were obtained from the applicable governmental agencies in the Kingdom of Saudi Arabia. We thank Frine Cardone from the Università Degli Studi di Bari for her support and effort during the collection of cerianthids in Taranto, Italy. Thanks go also to Michèle Loneux (MZULG), Ole Tendal (ZMUC), Leen van Ofwegen (Naturalis), Stephen Cairns and Geoff Keel (Smithsonian Institution) and Eric Laso-Wasem (Peabody Museum) for allowing the study of type material of Ceriantharia and to Charlotte Seid (SIO) for accessioning specimens. This research was partly performed in the framework of the state assignment of FASO Russia (theme number 0149-2019-0009) (T.M., identification of voucher specimens). Financial support was obtained from the faculty of Science of Uppsala University to C.Ö. We also thank Andrea Travaglini, Professor Marzia Bo, Simonepietro Canese, Federico Betti, Roberto Arrigoni, Marija Kupresanin, Professor Danwei Huang, Professor Marco Bertolino, Professor Riccardo Cattaneo, Marco Segre and Phil Zerofski for their help during the collection of the cerianthids from Gulf of Naples, Capo Noli, Al-Fasal, north Sulawesi, La Jolla and San Clemente Island. We thank Bernhard Ruthensteiner for his help with the museum collection at the Zoologische Staatssammlung München. We are grateful to Robert Vrijenhoek (MBARI) for inviting G.W.R. on a cruise to the Del Mar methane seep. Thanks also to the crews of the RV Western Flyer and the pilots of the ROV Doc Ricketts for their expertise. The authors also thank the reviewers of this manuscript