Litophyton dipensis sp. nov.

(Figs. 2c, 6-7, 12a)

Material examined. Holotype NTM C362, February 1978, coll. D. Schubot; paratype NTM C4141, Queensland, Great Barrier Reef, Dip reef, depth 5-10 m, 6 February 1981, coll. Z. Dinesen.

Description. The holotype NTM C362 is 7 cm high and 10,5 cm wide, the stalk is 2 cm high (Fig. 12a). The polyps are up to 0.65 mm wide and 0.50 mm high, and grouped in conical catkins.

Polyps. With irregular arrangement of sclerites in eight points (Fig. 2c). Abaxial and lateral point sclerites are spindles with simple tubercles and spiny distal part, largest present abaxially, up to 0.45 mm long (Fig. 6a), towards the adaxial points they become smaller (Fig. 6b). Tentacles with curved scales up to 0.10 mm long (Fig. 6c). Adaxial side of the polyp stalk with straight rods up to 0.12 mm long (Fig. 6d). Supporting bundle composed of one or two spindles up to 1.50 mm long, with simple tubercles and a spiny tip projecting for a maximum distance of 0.70 mm (Fig. 6e). Many polyp sclerites have an optically black inner core.

Surface layer top stalk. Capstans, derivatives of capstans, spindles and unilaterally spinose spindles. The spindles are up to 0.80 mm long, with simple and complex tubercles and long spines (Fig. 6 f-g).

Surface layer base stalk. Capstans, derivatives of capstans, spindles, and unilaterally spinose spindles, up to 0.60 mm long, with complex tubercles and very long spines (Fig. 7a).

Interior stalk. Spindles with pointed or blunt ends, up to 1.00 mm long and smaller irregular forms (Fig. 7 b-c), with simple and complex tubercles (Fig. 7d).

Etymology. Named after the locality of the paratype.

Distribution. Great Barrier Reef: Dip reef.

Remarks. This is the only species with projecting supporting bundle and blunt interior spindles. The unilaterally spinose sclerites with very long spines are very distinctive but in group I are also present in L. elfordensis sp. nov., L. graafae sp. nov., and L. myrmidonensis sp. nov. However, L. dipensis has many interior stalk spindles with blunt ends, in L. elfordensis they are branched, in L. graafae they are pointed with very coarse tubercles, and in L. myrmidonensis they are very slender.