Azooxanthellate Scleractinia (Cnidaria, Anthozoa) from South Africa Author Filander, Zoleka N. https://orcid.org/0000-0002-6905-4440 Biodiversity and Coastal Research, Oceans and Coasts, Department of Environment, Forestry, and Fisheries, Cape Town, South Africa & Zoology Department, Nelson Mandela University, Port Elizabeth, South Africa zfilander@gmail.com Author Kitahara, Marcelo V. Universidade Federal de Sao Paulo, Departamento de Ciencias do Mar, Santos, Brazil & Centro de Biologia Marinha, Universidade de Sao Paulo, Sao Sebastiao, Brazil Author Cairns, Stephen D. Department of Invertebrate Zoology, Smithsonian Institution, Washington DC, USA Author Sink, Kerry J. South African National Biodiversity Institute, Cape Town, South Africa & Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa Author Lombard, Amanda T. Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa text ZooKeys 2021 2021-10-28 1066 1 198 http://dx.doi.org/10.3897/zookeys.1066.69697 journal article http://dx.doi.org/10.3897/zookeys.1066.69697 1313-2970-1066-1 133CE040A5AF44F1BC9A558C2F06A8AA BD84F4C3157550C9B64120B2BE53F01A Dendrophyllia dilatata van der Horst, 1927 Fig. 8M, N Dendrophyllia dilatata van der Horst, 1927: 2-3, figs 2-4. - Zibrowius and Gili 1990 : 44. - Cairns and Keller 1993 : 278-279 . -Cairns 1994 : 89. - Cairns 2001 : 34. Type locality. Off Richards Bay, South Africa (RV 'Pieter Faure' stn. 12103: ca. 28°47'00.0"S , 32°20'00.0"E ); 97 m ( van der Horst 1927 ). Type material. The holotype is deposited at the ZMA ( Creuwels 2020 ). Material examined. SAMC_A073016 ( 2 specimens ): Eastern margin, 31 km from Richards Bay / 46 km Mlalazi Estuary , 29°00'54.00"S , 32°15'35.99"E ; 500 m . SAMC_A073068 ( 1 specimen ): Eastern margin, 47 km from Cape Vidal / 28 km off Mgobezeleni Estuary , 27°43'11.99"S , 32°40'36.11"E ; 100 m . Description. Colony unattached and arborescent, with sympodial branching formed by extra-tentacular budding. Corallum ceratoid to sub-cylindrical, straight to slightly curved. Largest specimen examined (SAMC_A073016) 105.5 mm in H, with ≤ 30 corallites. Calice elliptical (GCD:LCD = 0.9-1.2), with serrated calicular margin. Epitheca absent. Costae well developed at upper corallum, rounded, granular, non-perforate, and separated by thin, porous, intercostal striae. Corallum white. Septa hexamerally arranged in four complete cycles according to the formula: S1-2> S4> S3 (48 septa). S1-2 both independent, reaching the columella with straight axial margins, which may also be finely serrated. S1 most exsert, followed by S2. S3 ~ 1/3 the width of S2. S4 slightly wider than flanked S3, arranged in Pourtales plan: in each half-system a pair of S4 fuses before S3 with jaggedly dentate axial margins. Fossa deep, containing a large, and slightly raised spongy columella. Distribution. Regional: Eastern margin of South Africa, off Richards Bay towards Cape Vidal; 97-500 m. Elsewhere: Mozambique ( Cairns and Keller 1993 ); 97-132 m. Remarks. Dendrophyllia dilatata resembles Dendrophyllia sp. 1 in its growth form: i.e., large, dendroid colonies with fairly regular sympodial arranged corallites (Cairns 1994 ). However, it can be distinguished by having four cycles of septa as compared with three ( Dendrophyllia sp. 1), a well-developed Pourtales plan development (poorly developed in Dendrophyllia sp. 1), lacking P2 which is present in Dendrophyllia sp. 1, and a larger columella (smaller in Dendrophyllia sp. 1).