Litophyton elfordensis sp. nov.

(Figs. 1 c-f, 2d-h, 8-11)

Material examined. Holotype, NTM C193, Queensland, Elford reef, 1 December 1976, coll. P. Alderslade ; paratypes: NTM C192, coll. P. Alderslade; NTM C4022, Queensland, Great Barrier Reef, Flinders Cay, depth 5-10 m, 24 November 1981, coll. Z. Dinesen; NTM C04135, Queensland, Great Barrier Reef, Davies reef, 10-15 m, 15 April 1981, coll. Z. Dinesen.

Description. The holotype NTM C193 is 5 cm high and 7 cm wide, the stalk is 3 cm high (Fig. 1c). The polyps are up to 0.80 mm wide and high, and are grouped in spherical catkins.

Polyps. With irregular arrangement of sclerites in eight points (Fig. 2 d-e). Abaxial and lateral point sclerites are spindles with simple tubercles, largest present abaxially, up to 0.40 mm long (Fig. 8a), with a leafy distal part; towards the adaxial points the spindles become smaller (Fig. 8b). Tentacles with curved scales up to 0.15 mm long (Fig. 8c). Adaxial side of the polyp stalk with straight rods up to 0.10 mm long (Fig. 8d). Supporting bundle composed of one or two spindles up to 2.00 mm long, with simple tubercles and a spiny tip projecting for a maximum distance of 0.40 mm (Fig. 8e). Many polyp sclerites have an optically black inner core.

Surface layer top stalk. Capstans, derivatives of capstans, spindles and unilaterally spinose spindles (Fig. 8 f-h), with complex tubercles and long spines. The spindles are up to 1.40 mm long.

Surface layer base stalk. Capstans, derivatives of capstans, spindles and unilaterally spinose spindles, up to 0.60 mm long, with complex tubercles (Figs 8i). The spines of the unilaterally spinose sclerites are very long.

Interior stalk. Branched spindles, mostly laterally, up to 2.00 mm long, with complex tubercles and pointed ends (Fig. 8 j-l).

Etymology. Named after the type locality.

Distribution. Great Barrier Reef: Elford reef, Flinders reef, Davies reef.

Remarks. This is the only species with projecting supporting bundle and leafy point spindles. The species shows a lot of variation regarding polyp armature (Fig. 2 d-h) and interior stalk sclerites, and therefore the colonies (Fig. 1 d-f) and sclerites (Figs. 9-11) of all paratypes are also presented. NTM C192 and NTM C4022 do not show branched internal spindles (Figs. 9j, 10g) but both specimens probably lack the base of the stalk (Fig. 1 d-e).

The unilaterally spinose sclerites with long spines are very distinctive in L. elfordensis but are also present in the group I species L. dipensis sp. nov., L. myrmidonensis sp. nov., and L. graafae sp. nov. The differences between these four species are discussed with L. dipensis .