A new genus of soft coral (Octocorallia, Malacalcyonacea, Cladiellidae) and three new species from Indo-Pacific coral reefs Author McFadden, Catherine S. https://orcid.org/0000-0002-8519-9762 Department of Biology, Harvey Mudd College, Claremont, CA 91711, USA mcfadden@hmc.edu Author Benayahu, Yehuda https://orcid.org/0000-0002-6999-0239 School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978, Tel Aviv, Israel Author Samimi-Namin, Kaveh https://orcid.org/0000-0002-7744-9944 Marine Evolution and Ecology Group, Naturalis Biodiversity Center, P. O. Box 9517, 2300 RA Leiden, Netherlands & Department of Biology, University of Oxford, Oxfordshire, Oxford OX 1 3 SZ, UK & Natural History Museum, Cromwell Road, London SW 7 5 BD, UK text ZooKeys 2024 2024-01-10 1188 275 304 http://dx.doi.org/10.3897/zookeys.1188.110617 journal article http://dx.doi.org/10.3897/zookeys.1188.110617 1313-2970-1188-275 528120A62EC04796B37B5E51FD1FE7AA 3ADC360B3D7D5B46BFD68CD765E7C3F0 Ofwegenum verseveldti (Benayahu, 1982) comb. nov. Figs 1 , 3F, G , 14 , 15 Material examined. Holotype . Egypt • Marsa Barieka , northern Red Sea , southern tip of Sinai Peninsula ; 27.7500°N , 34.2333°E ; 12 m depth ; 3 July 1978 ; coll. Y. Benayahu ; SMNHTAU_ Co _25554 (previously NS16770). Paratypes . Egypt • 33 colonies, same data as holotype ; SMNHTAU_Co_25544 (previously NS16771) • same data as holotype ; RMNH COEL. 13903. Other material. Israel • Eilat , northern Gulf of Aqaba , mesophotic reef across from the Inter University Institute for Marine Sciences (IUI); 60 m depth ; 20 September 2005 ; coll. S. Eibinder ; SMNHTAU_ Co _33097 . Re-description (modified after Benayahu 1982 ). The holotype is a capitate colony, 11 mm in diameter with stalk approximately 14 mm high (Fig. 3F ). The contracted polyps form conical or dome-shaped mounds, and the distal ends of some tentacles can be seen protruding from them. The coenenchyme sclerites are spindles and rods up to 0.80 mm long with low, simple tubercles or areas of thickening forming concentric, raised rings (Fig. 14A ). The polyp body contains similar but shorter sclerites, up to 0.45 mm long (Fig. 14A ), that appear to be arranged 'en chevron' when the polyp is extended. The size of the sclerites decreases along the polyp body towards the base of the tentacles. Figure 14. Ofwegenum verseveldti comb. nov., holotype SMNHTAU_Co_25554 A sclerites of the coenenchyme and polyp body B sclerites of the tentacles. The tentacles and pinnules include numerous crosses, flattened rods (i.e., finger-biscuits) and platelets up to 0.10 mm long (Fig. 14B ), arranged on the aboral side of the tentacles. Some of these sclerites have median constrictions, side notches, or depressions at one or both ends that resemble a figure-eight shape (Fig. 14B ). The platelets commonly have an asymmetrical outline and are wider at both ends (Fig. 14B ). Colour. In life the coenenchyme is uniquely dark blue. The expanded polyps are pale blue, with brown pinnules that reflect the presence of symbiotic algae. The ethanol-preserved colony is creamy yellow, and the tentacles are pale cream. Morphological variations. The paratype colonies and the other material vary in size; some colonies feature two separate polyparies on a common stalk (Fig. 3G ). RMNH COEL. 13903 has smoother spindles and rods in both the coenenchyme and polyp body (Fig. 15A ) and has fewer figure-eight platelets (Fig. 15B ) compared to the holotype. Figure 15. Ofwegenum verseveldti comb. nov., paratype, RMNH COEL. 13903 A sclerites of the coenenchyme and polyp body B sclerites of the tentacles. Remarks. Ofwegenum verseveldti comb. nov. is the only species with tentacle sclerites composed mainly of asymmetrical platelets resembling a figure-eight (Figs 14B , 15B ). Additionally, it has the longest spindles and rods among the congeners (Figs 14A , 15A ). The current findings correspond to the original description of M. verseveldti (see Benayahu 1982 ). The new high-quality SEM images of the sclerites (Figs 14 , 15 ) better present the species' diagnostic morphological characters. The tentacle sclerites reported as 'flattened rods with tiny pits' in the original description are referred to here as figure-eight platelets. The maximum length of these sclerites was erroneously presented by Benayahu (1982 : 198, up to 0.19 mm) and is now corrected to be up to 0.10 mm (Fig. 14B ). In the original description the species was described as having polyp sclerites arranged as a collaret and points, however further examination of additional material shows that is not the case. When polyps are extended the spindles and rods appear to be arranged 'en chevron' . Benayahu (1982) also did not mention anything about the presence or absence of zooxanthellae in specimens. Re-examination of the type material confirms that O. verseveldti is indeed zooxanthellate. It should be noted that despite the extensive soft coral research conducted in the Gulf of Aqaba and and other parts of the Red Sea, since the collection of the type material of O. verseveldti comb. nov. it has been found only once at a mesophotic depth on the Eilat reef (see above: SMNHTAU_Co_33097) and is also only infrequently observed by some professional divers in that region. This species should thus be considered as a rare soft coral in the Red Sea. Distribution. Northern Red Sea.