Acropora arafura, Wallace & Done & Muir, 2012

Wallace, Carden C., Done, Barbara J. & Muir, Paul R., 2012, Revision and catalogue of worldwide staghorn corals Acropora and Isopora (Scleractinia: Acroporidae) in the Museum of Tropical Queensland, Memoirs of the Queensland Museu Nature 57, pp. 1-258 : 18

Acropora arafura sp. nov.

( Fig. 7)

Type locality. Australia: Northern Territory: Gove, Arafura Sea.

Material examined. HOLOTYPE: MTQ-G60418, Gove, Arafura Sea, Northern Territory, Australia, 12°10.6’S, 136°4.0’E, depth 0.5–2.5 m, C.C. Wallace, 30.07.2005.

PARATYPES: MTQ-G60419, Gove, Arafura Sea, NT, 12°10.6’S, 136°43.0’E, depth 0.5– 2.5 m, C.C. Wallace, 30.07.2005. MTQ-G60420, Gove, Arafura Sea, NT, 12°11.0’S, 136°40.2’ E, depth 1–3 m, C.C. Wallace, 30.vii.2005. MAGNT-C48136, reef off Gunn Point, Darwin, NT, 12°14’S, 130°0’E, depth and date unknown (MTQ-G61777 is a fragment of this paratype). MAGNT-C625 2, Dudley Point, Darwin, Northern Territory, 12°25’S, 130°49’E, depth and date unknown, (MTQ-G61778 is fragment of this paratype).

OTHER MATERIAL: MTQ-G63138, Turban I., Bonaparte Archipelago, West Kimberley, Western Australia, 14°28.30’S, 124°59.36’E, depth 1–7 m, C.C. Wallace, 28.10.2007. MTQ-G63145, Albert Is, Bonaparte Archipelago, West Kimberley, WA, 14°32.5’S, 124°55.7’E, depth 1–7 m, P. Muir, 29.10.2007. MTQ-G64399, Turban I., Bonaparte Archipelago, West Kimberley, WA, 14°29.30’S, 124°59.36’E, depth 1–7 m, C.C. Wallace, 30.10.2007.

Species group: not determined.

Skeletal characteristics of holotype: part of colony, 112 mm greatest width and 90 mm height. Corallum is caespitose, consisting of numerous terete branches, 5.0 to 20 mm length (final branch), 4.5 to 5.5 mm in diameter, that give off shorter branches at regular intervals along their length. Corallites: axial corallites outer diameter 1.8 to 2.3 mm, inner diameter 0.8 to 1.1 mm, primary septa all present up to ¾ R, secondary septa absent or a few present up to 1/3 R; radial corallites rounded appressed tubular with round openings; all of similar size, regularly arranged, mostly not touching, primary septa all present up to 2/3 R, directives longer; secondary septa: some present as points. Coenosteum the same on and between radial corallites: reticulate with regularly arranged, slightly elaborated spinules.

Variations shown in paratypes: G60420 and G60419 branches are 4.5 to 6.5 mm in diameter; corallites with slightly thickened outer walls.

Description. Colony outline: indeterminate, predominantly caespitose. Branches: tertiary branching order absent; length:>25 mm; diameter: 4.5–6.5 mm, radial-dominated, terete; radial crowding: some touching; axial/radial ratio:>1:10. Axial corallites: three synapticular rings; porous; outer diameter 1.8–2.3 mm; inner diamer 0.8–1.1 mm; primary septa to ¾ R. Radial corallites: medium; two synapticular rings; one size or graded; inner wall not developed; shape: rounded appressed; openings: ovalrounded; primary septa to 2/3 R. Coenosteum: same on and between radials: reticulate; spinule shape: elaborated.

Field characteristics. Colour cream to pale brown, colonies caespitose, spreading to around 0.5 m diameter.

Habitat. Intertidal, sandy reef flats between 0.5 and 7 m depth.

Distribution. Eastern Indian Ocean: Western Australian coast, Kimberley region; north Australia: Arafura Sea.

Etymology. Named for the type locality, the shallow sea to the north of Australia.