Cycloseris hexagonalis ( Milne Edwards & Haime, 1848 )

Lane, David J. W. & Hoeksema, Bert W., 2016, Mesophotic mushroom coral records at Brunei Darussalam support westward extension of the Coral Triangle to the South China Sea waters of Northwest Borneo, Raffles Bulletin of Zoology 64, pp. 204-212 : 207

Cycloseris hexagonalis ( Milne Edwards & Haime, 1848)

( Figs. 3A–D )

Fungia hexagonalis Milne Edwards & Haime, 1848: p. 89 , pl. 6 Figs. 2–2f

Cycloseris hexagonalis – Milne Edwards & Haime, 1851: p. 113; Veron, 2000 (partim.): p. 239, Fig. 4; Gittenberger et al., 2011: Table 7; Hoeksema, 2012a: Fig. 6; Hoeksema, 2014: 75.

Fungia (Cycloseris) hexagonalis – Hoeksema, 1989: p. 59–64, Figs. 123–135, 613; Hoeksema, 1993a: 5; Hoeksema & van Ofwegen, 2004: [4 Figs.]

Fungia hexagonalis – Hoeksema, 2008: Fig. 8.

Material examined. Five specimens, collected by DJWL 8 November 2014 at 32 m depth, South China Sea , Mampak Patches , North Patch : N05°02.305’ E114°26.449’. Habitat : reef top, silty sand and rock amongst gorgonian fan corals and whip corals. Monostomatous and free-living. Skeletal diameters (maximum) range from (1) 58 mm; (2) 62 mm; (5) 64 mm; (3) 65 mm; (4) 66 mm. Specimens are lodged with following Catalogue Numbers and Institutions : 1 & 5: RMNH Coel.42102 @ RMNH; 2: UBDM.6.201411.1 @ UBDRC; 3 & 4: ZRC.CNI.1008 & ZRC.CNI.1009 @ LKCNHM. All specimens are full-grown with the corallum outline irregularly circular or slightly oval, but with marked upwardly-directed undulations giving an irregularly concave shape to the thin corallum ( Figs. 3A–D ). In one specimen ( RMNH Coel.42102b) the under faces of two of the four corallum folds are completely fused ( Fig. 3D ). Septa tightly packed with lower order ones thick, exsert and solid. Thin, higher order septal fenestrations, if present, not visible due to dense packing of septa. Septal margins of lower series ornamented with fine conical or blunt dentations that grade into the dense granulations of the septal sides and are, in consequence, difficult to count. The marginal ornamentation of the fine septae shows coalescing expansions centrally. Small, pointed costal spines near the corallum margin generally number less than 50 per cm .

Figures

Fig. 3. A–D, Cycloseris hexagonalis [RMNH Coel.42102]; A, RMNH Coel.42102b photographed in situ, oral view; B, bleached skeleton, same specimen, oral view; C, underside of the same specimen, biofouled with serpulid polychaetes. D, RMNH Coel. 42102a. Corallum undulations are extreme and for two of them (upper and lower in the image) the undersurfaces of the corallum folds are fused. E, F, Lithophyllon spinifer [RMNH Coel.42103]. E, photographed in situ, oral view; F, bleached, oral view. Scale bars = 1cm.

Fig. 2. View of the benthic community at the top of Mampak Patches, Brunei Darussalam (32 m deep).