Acropora sirikitiae Wallace, Phongsuwan & Muir, 2012

(Fig. 91)

Acropora sirikitiae Wallace, Phongsuwan & Muir, 2012: 119, figs 1, 2.

Type locality. Huyong Island, Similan Islands, Thailand.

MTQ Holdings. HOLOTYPE G55364; PARATYPES G55352–53, G55357, G55362, G55382, G55389, G55392–93, G59316, G55394, G63005 Thailand.

Species group: divaricata .

Description. Colony outline: indeterminate, arborescent. Branches: tertiary branching order absent; length: 50–100 mm; diameter: 2.5–4.9 mm, radial dominated, tapering; radial crowding: some touching; axial/radial ratio:>1:10. Axial corallites: three synapticular rings; not porous; outer diameter 1.4–2.5 mm; inner diameter 0.6–1.1 mm; primary septa to 1/3 R. Radial corallites: medium; three synapticular rings; one size or graded; inner wall developed; shape: appressed tubular; openings: oval-round- ed; primary septa to ¾ R. Coenosteum: same on and between radials: dense spinules; spinule shape: elaborate.

Taxonomic note. This species is the first recorded member of the A. divaricata species group with indeterminate colony growth.