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 Rhizotrochus typus Milne-Edwards & Haime, 1848 Fig. 12E-H Rhizotrochus typus Milne-Edwards & Haime, 1848a 282, pl. 8, fig. 16 . - Pourtales 1871 : 13. - Studer 1881 : 28. - Moseley 1881 : 131. -von Marenzeller 1907: 23, pl. 2, fig. 5. - Yabe and Sugiyama 1936 : 346-348, figs 3, 3A. - Cairns 1989a : 79-81, pl. 41, figs F, J . -Cairns 1994 81, pl. 35, figs A-C, pl. 40, figs H, I. - Cairns and Zibrowius 1997 : 161, figs 22D, E. - Cairns 1999a : 127, fig. 22A. - Cairns et al. 1999 : 31 . -Tachikawa 2005 : 10-11, pl. 4, figs E-H. - Cairns 2009 : 21. - Kitahara and Cairns 2021 : 234-236, figs 120F-G, 121. Flabellum rubrum . -Gardiner 1902 a: 125-152, pl. 4, fig. 34 . -Gardiner 1902 b: 464-471. Flabellum harmeri . - Boshoff 1981 : 35. Monomyces sp. - Boshoff 1981 : 35. Type locality. Singapore, depth unknown (Cairns 1994 ). Type material. Two syntypes are deposited at the MNHNP (Cairns 1994 ). Material examined. ORI_DIIb3 (in part: 1 specimen ): Locality data unknown, 27 m . ORI_DIIc1 ( 4 specimens ), SAMC_A072990 ( 1 specimen ): Locality data unknown. SAMC_A073048 ( 1 specimen ): Locality data unknown; SAMC_A073194 ( 2 specimens ): Southern margin, 5 km from Gonubie / 3 km off Gqunube Estuary , 32°57'11.87"S , 28°02'48.12"E ; 30 m . SAMC_A073247 ( 3 specimens ): Eastern margin, 34 km from Coffee Bay / 7 km off Ntlonyane Estuary, 32°15'11.99"S , 28°57'41.99"E ; 160 m . SAM_ A90094 ( 2 specimens ): Eastern margin, 34 km from Coffee Bay / 16 km from Ntlonyane Estuary , 32°16'59.99"S , 29°03'59.99"E ; 160 m . UCTES_SCD39B ( 3 specimens ): Eastern margin, 34 km from Coffee Bay / 16 km from Ntlonyane Estuary, 32°16'59.99"S , 29°03'59.99"E ; 160 m Imagery data. BMNH 1939.7.20.816-833 (1 specimen), BMNH 1950.1.10.34 (1 specimen), BMNH 1950.10.97-102 (1 specimen), BMNH 1950.1.11.63 (1 specimen): Cape of Good Hope, other locality data unknown. Description. Corallum conical, robust, and attached to substrate by a slender and non-reinforced pedicel (<3 mm in D). Calice irregularly elliptical (GCD:LCD = 1.2-1.5), with thin, smooth, and flared calicular margin. Largest specimen examined (SAMC_A072990) 14.4 x 9.8 mm in CD, and 21.1 mm in H. Theca thin and usually encrusted, lower theca bears numerous (> 5) hollow rootlets that improve corallum anchoring (rootlets of examined specimens broken). Costae equally wide but poorly developed. Intercostal striae shallow. Transversal chevron-shaped growth lines present from calicular margin towards pedicel. Corallum predominantly white, becoming light-beige from lower theca towards base. Septa hexamerally arranged in six cycles, last being incomplete, according to the formula: S1-2> S3> S4> S5> S6. However, specimens examined also have fifth cycle incomplete (totalling 78-89 septa). S1-2 equal in width and have straight and vertical axial margin, which become slightly sinuous deeper in the fossa. Higher cycle septa (S3-5) progressively smaller, and bearing slightly sinuous axial margins. S6 if present rudimentary, but, if absent, then S5 rudimentary. Septal faces finely granulated. Fossa deep, with rudimentary or absent columella. Distribution. Regional: Southern and eastern margin of South Africa, off Gonubie extending Coffee Bay; 30-160 m. Elsewhere: Andaman Islands; Bay of Bengal ( Alcock 1893 ); Red Sea (von Marenzeller 1907); Japan ( Cairns 1989b , 1994); South China Sea; Philippines; Indonesia ( Cairns and Zibrowius 1997 ); Vanuatu ( Cairns 1999a ); New Caledonia ( Kitahara and Cairns 2021 ); 20-1048 m. Remarks. Although Rhizotrochus typus was collected off the South African margin (Cape of Good Hope) in the early 20th century, it was incorrectly identified by Gardiner (1902 a, 1902b) as Flabellum rubrum . Subsequently, Boshoff (1981) misidentified R. typus as two other flabellids ( F. harmeri [ORI_DIIb3] and Monomyces sp. [ORI_DIIc1]). Rhizotrochus has long been synonymiszed with Monomyces , however historical accounts have outlined the difference in the number and placement/pattern of their rootlets, in which Rhizotrochus has> 2 rootlets that are not fused to pedicel as compare with Monomyces Ehrenberg, 1834, which displays <2 rootlets fused to the pedicel ( Cairns 1989a ). Despite the examined specimens having broken rootlets (thus not showing whether they join pedicel or not), we herein provide the first reliable record for the species within South African localities by use of the number of rootlets (> 5) observed.