Search for mesophotic octocorals (Cnidaria, Anthozoa) and their phylogeny: I. A new sclerite-free genus from Eilat, northern Red Sea Author Benayahu, Yehuda Author McFadden, Catherine S. Author Shoham, Erez text ZooKeys 2017 680 1 11 http://dx.doi.org/10.3897/zookeys.680.12727 journal article http://dx.doi.org/10.3897/zookeys.680.12727 1313-2970-680-1 578016B2623B4A7584294D122E0D3279 Altumia gen. n. Diagnosis. Clavulariinae with a thin and soft encrusting base, sometimes resembling a short stolon. Polyps erect when expanded, separate from each other; the stolon may feature a few polyps, occasionally only one. Polyps fully retractile into base of the colony, forming low truncated dome-shaped mounds. No sclerites in any part of the colony. Colonies lack symbiotic algae (zooxanthellae). Type species: Altumia delicata sp. n. by original designation and monotypy. Etymology. The generic name is derived from the Latin 'altum' , deep, referring to the habitat of the new genus at MCE depths and beyond. Gender female. Molecular results. Maximum likelihood and Bayesian analyses yielded identical tree topologies that both support the phylogenetic placement of Altumia n. gen. as the sister taxon to Acanthoaxis wirtzi ( Acanthoaxiidae ), within a larger well-supported clade that also includes the Clavulariidae genera Carijoa F. Mueller , 1867 and Cryptophyton Williams, 2000 (Figure 1). Pairwise genetic distances (Kimura 2-parameter) between Altumia n. gen. and Acanthoaxis (mtMutS: 9.4%, COI: 2.9%) are comparable to values among different genera and some family-level clades of octocorals ( McFadden et al. 2011 ). Figure 1. Phylogenetic relationships among species of octocorals that lack sclerites (red asterisks) and members of family Clavulariidae (blue labels), including Altumia delicata gen n. sp. n. (red label). Solid circles at nodes indicate strong support from both maximum-likelihood (bootstrap value>70%) and Bayesian (posterior probability>0.90) analyses; split circles indicate strong support from one analysis only (left half solid: supported by ML; right half solid: supported by Bayesian analysis). Strongly supported clades that include no clavulariid or sclerite-free species have been collapsed. Hexacorallian outgroup taxa used to root tree are not shown. For a comprehensive list of taxa and sequences included in the analyses see McFadden and Ofwegen (2012) .