Litophyton brachiatum sp. nov.

(Figs. 69 a-c, 70a-c, 71-75)

Material examined. Holotype NTM C4154, Queensland, Great Barrier Reef, Davies reef, depth 5-10 m, 15 April 1981, coll. Z. Dinesen ; paratypes: NTM C1373, Queensland, Great Barrier Reef, Swain reefs, Sweet-lip reef, 15 November 1980, coll. P. Alderslade; NTM C1380-NTM C1385, Queensland, Swain reefs, Sanctuary reef, 13 November 1980, coll. P. Alderslade; NTM C 1473-1474, Queensland, Sanctuary reef, 13 November 1980, coll. P. Alderslade; NTM C3967, Queensland, Great Barrier Reef, Davies reef, depth 5-10 m, 16 April 1981; NTM C4139, Queensland, Great Barrier Reef, Davies reef, depth 5-10 m, 16 April 1981, coll. Z. Dinesen; NTM C4179, Queensland, Great Barrier Reef, John Brewer reef, depth 1-5 m, 7 February 1981, coll. Z. Dinesen; NTM C4283, Queensland, Great Barrier Reef, Dip reef, depth 5-10 m, 5 February 1981, coll. Z. Dinesen.

Description. The NTM C4154 holotype is 12 cm high and 9 cm wide (Fig. 69a). The colony consists of two main stalks fused at the base, one 4 cm long, the other 5 cm long. The polyps are up to 0.8 mm wide and 1 mm high, mostly with expanded tentacles, and grouped in conical catkins.

Polyps. With irregular arrangement of sclerites in eight points (Fig. 70a). Abaxial and lateral point sclerites are spindles with spines, largest present abaxially, up to 0.40 mm long (Fig. 71a), laterally they are up to 0.20 mm long (Fig. 71b). In the adaxial points there are small curved scales, similar to those of the tentacles, up to 0.10 mm long (Fig. 71c). Straight small rods are very abundant on the adaxial side of the polyp stalk, up to 0.05 mm long, many of them with enlarged ends (Fig. 71d). Spindles of the supporting bundle are up to 1.50 mm long, with simple tubercles (Fig. 71e), and not projecting beyond the polyp or only slightly so.

Surface layer top stalk. Capstans and derivatives of capstans, 0.05-0.10 mm long; spindles and unilaterally spinose spindles are also present, up to 0.7 mm long. The smaller sclerites with simple tubercles (Fig. 71f), the larger ones with complex tubercles (Fig. 71g).

Surface layer base stalk. Capstans, derivatives of capstans, and unilaterally spinose spheroids (Figs. 71h, 72a), and a few spindles and unilaterally spinose spindles (not depicted). Capstans 0.05-0.20 mm long; spindles up to about 0.70 mm long. The smaller sclerites with simple tubercles (Fig. 72a), the larger ones with complex tubercles (Fig. 71h)

Interior stalk. Spindles, many with side branches (Fig. 72c), up to 2 mm long with pointed ends and prickly complex tubercles (Fig. 72d). Smaller spindles are flattened with less tubercles (fig. 72b).

Etymology. The Latin brachiatum, branched, branchiate, refers to the branched interior stalk spindles.

Distribution. Queensland, Great Barrier Reef: Davies reef, Dip reef, John Brewer reef.

Remarks. The microscope slides of NTM C1373, NTM C1473 (Figs. 69b, 70b), and NTM C4139, and the SEM images of the latter two (Figs. 73-74) showed less branched interior stalk spindles. Extra temporary slides of the interior stalk of NTM C1473 and NTM C4139 showed them. NTM C1473 shows some supporting bundle spindles with smooth tip (Fig. 73e)

NTM C1380-NTM C1385 were checked with temporary slides only.

NTM C4179 (Fig. 69c) is with some doubts included in this species. The sclerites of the interior of the base of the stalk did not show a single branched spindle (Fig. 75i), extra temporary slides also did not show them. Furthermore, no clear view of the arrangement of the polyp sclerites could be achieved (Fig. 70c). Notably, its sclerites (Fig. 75) are not different from the other specimens belonging to this species; especially the polyp rods with enlarged ends are strikingly similar (Fig. 75d).

L. bayeri (Verseveldt, 1966) from the Moluccas, Indonesia, (Figs. 69d; 70d) resembles this species. It has similar shaped polyp sclerites (Fig. 76 a-c) but far fewer polyp stalk rods (Fig. 76d). The surface stalk sclerites are also different (Fig. 76 f-g), mostly spindles and unilaterally spine spindles. Also the interior stalk sclerites differ (Fig. 76 h-j), but this could have been caused by the missing basal part of the stalk of L. bayeri .

L. debilis (Kükenthal, 1895) (Ternate) (Figs. 69e, 77) resembles this species even more, but differs by having much smaller interior stalk spindles, only up to 1 mm long (Fig. 77l).