Litophyton brachiatum, Van, 2020

Van Ofwegen, Leen P., 2020, The genus Litophyton Forskål, 1775 (Octocorallia: Alcyonacea: Nephtheidae) from Australia, Zootaxa 4764 (1), pp. 1-131 : 80-84

publication ID	https://doi.org/ 10.11646/zootaxa.4764.1.1
publication LSID	urn:lsid:zoobank.org:pub:53C5289A-156C-4AF1-B84A-73099A332C05
DOI	https://doi.org/10.5281/zenodo.3803604
persistent identifier	https://treatment.plazi.org/id/03BCB717-236E-FF83-FF35-86CEFC85F8E8
treatment provided by	Carolina
scientific name	Litophyton brachiatum
status	sp. nov.

Treatment

Litophyton brachiatum View in CoL sp. nov.

( Figs. 69 View FIGURE 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 View FIGURE 69 ). 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 View FIGURE 70 ). Abaxial and lateral point sclerites are spindles with spines, largest present abaxially, up to 0.40 mm long ( Fig. 71a View FIGURE 71 ), laterally they are up to 0.20 mm long ( Fig. 71b View FIGURE 71 ). In the adaxial points there are small curved scales, similar to those of the tentacles, up to 0.10 mm long ( Fig. 71c View FIGURE 71 ). 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 View FIGURE 71 ). Spindles of the supporting bundle are up to 1.50 mm long, with simple tubercles ( Fig. 71e View FIGURE 71 ), 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 View FIGURE 71 ), the larger ones with complex tubercles ( Fig. 71g View FIGURE 71 ).

Surface layer base stalk. Capstans, derivatives of capstans, and unilaterally spinose spheroids ( Figs. 71h View FIGURE 71 , 72a View FIGURE 72 ), 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 View FIGURE 72 ), the larger ones with complex tubercles ( Fig. 71h View FIGURE 71 )

Interior stalk. Spindles, many with side branches ( Fig. 72c View FIGURE 72 ), up to 2 mm long with pointed ends and prickly complex tubercles ( Fig. 72d View FIGURE 72 ). 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 View FIGURE 69 , 70b View FIGURE 70 ), and NTM C4139, and the SEM images of the latter two ( Figs. 73-74 View FIGURE 73 View FIGURE 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 View FIGURE 73 )

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

NTM C4179 ( Fig. 69c View FIGURE 69 ) 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 View FIGURE 75 ), extra temporary slides also did not show them. Furthermore, no clear view of the arrangement of the polyp sclerites could be achieved ( Fig. 70c View FIGURE 70 ). Notably, its sclerites ( Fig. 75 View FIGURE 75 ) are not different from the other specimens belonging to this species; especially the polyp rods with enlarged ends are strikingly similar ( Fig. 75d View FIGURE 75 ).

L. bayeri ( Verseveldt, 1966) from the Moluccas, Indonesia, ( Figs. 69d View FIGURE 69 ; 70d View FIGURE 70 ) resembles this species. It has similar shaped polyp sclerites ( Fig. 76 View FIGURE 76 a-c) but far fewer polyp stalk rods ( Fig. 76d View FIGURE 76 ). The surface stalk sclerites are also different ( Fig. 76 View FIGURE 76 f-g), mostly spindles and unilaterally spine spindles. Also the interior stalk sclerites differ ( Fig. 76 View FIGURE 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 View FIGURE 69 , 77 View FIGURE 77 ) resembles this species even more, but differs by having much smaller interior stalk spindles, only up to 1 mm long ( Fig. 77l View FIGURE 77 ).