Briareum hamrum (Gohar, 1948)

Samimi-Namin, Kaveh & van Ofwegen, Leen P., 2016, Overview of the genus Briareum (Cnidaria, Octocorallia, Briareidae) in the Indo-Pacific, with the description of a new species, ZooKeys 557, pp. 1-44 : 7-11

Taxon classification Animalia Alcyonacea Briareidae

Briareum hamrum (Gohar, 1948) Figures 8, 9, 10, 2 E–F, 11 A–B, 26 A–B

? Sympodium punctatum May, 1898: 11 (Tumbatu, Zanzibar); Thomson and Henderson 1906: 408, pl. 29 fig. 9 (Chuaka, Tanzania); Tixier-Durivault 1966: 104, figs 96-97 (Madagascar).

? Sympodium splendens Thomson & Henderson, 1906: 409, pl. 29 fig. 8 (Chuaka, Tanzania).

? Alcyonium (Erythropodium) contortum Kükenthal, 1906: 50, pl. 7 figs 34-36, pl. 8 figs 37-38 (Red Sea, Tor, Jimschi).

? Solenopodium contortum Kükenthal, 1919: 41; Stiasny 1937: 10, fig. B (re-examination type).

Clavularia hamra Gohar, 1948: 4, figs 1-5 (Hurghada, Red Sea); Verseveldt 1970: 209 (Eilat).

Solenopodium violaceum Broch & Horridge, 1956: 157 (Hurghada, Red Sea).

Briareum hamrum ; Alderslade 2000: 246; Benayahu et al. 2003: 51 (Bazaruto Island, Mozambique).

Briareum hamra [sic]; Alderslade and McFadden 2007: 42.

Material examined.

RMNH Coel. 6809, Red Sea, coll. L.F. Fishelson, NS 6468, det. J. Verseveldt; RMNH Coel. 41406, Madagascar, Tuléar, coll. Nicole Gravier-Bonnet (179), 1967-69, don. H. Zibrowius, Centre d’Oceanologie de Marseille, Station Marine d’Endoume; RMNH Coel. 41407, Iran, Persian Gulf, north of Kish Island, 26°34.512'N 53°59.320'E, 10 m depth, coll. K. Samimi-Namin, 1 October 2009; RMNH Coel. 41408, Iran, Strait of Hormuz, Persian Gulf, north of Larak Island, 26°53.304'N 56°23.769'E, depth 12 m, coll. K. Samimi-Namin, 17 February 2009; RMNH Coel. 41409-41411, Oman, Daymaniyat Islands, 23°51.965'N 58°5.606'E, coll. K. Samimi-Namin; RMNH Coel. 41412, Persian Gulf, north of Farur Island, depth 12-15 m, 10 February 2010, coll. K. Samimi-Namin; RMNH Coel. 41413, Oman, Daymaniyat Islands, 23°51.720'N 58°6.253'E, depth 18 m, coll. K. Samimi-Namin, 23 April 2011; RMNH Coel. 41414, Oman, Daymaniyat Islands, 23°51.720'N 58°6.253'E, depth 18 m, coll. K. Samimi-Namin, 23 April 2011; RMNH Coel. 41415, Oman, Daymaniyat Islands, 23°51.720'N 58°6.253'E, depth 18 m, coll. K. Samimi-Namin, 23 April 2011.

Diagnosis.

Calyx with straight spindles containing small tubercles arranged in transverse rows and flattened spindles (Figure 8A). Cortex with straight or bent spindles with complex tubercles (Figure 8B). Coenenchymal sclerites 0.10-0.35 mm long. Medulla additionally has branched sclerites with simple or complex tubercles (Figure 8C). These sclerites are slightly shorter, up to 0.30 mm long. Sclerites of the surface layer are colourless; interior sclerites are magenta.

Remarks.

Alderslade (2000) referred Clavularia hamra Gohar, 1948 to Briareum , consequently the species name had to be changed to hamrum .

Gohar (1948: 10) compared his Clavularia hamra with both Sympodium punctatum May, 1898 and Sympodium splendens Thomson & Henderson, 1906, and noticed their close resemblance. According to Gohar (1848), Sympodium punctatum differs in having sclerites up to 0.266 mm long while they are up to 0.35 mm long in Clavularia hamra . Sympodium splendens differs in having two rows of pinnules on either side of the tentacles, each row consisting of 20-24 pinnules, while in Clavularia hamra there is only one row of 16-22 pinnules, which are much longer. However, an odd second row of 1-3 pinnules can be present in Clavularia hamra . Furthermore, Clavularia hamra has no triradiate or tetraradiate sclerites, described for Sympodium splendens . Next to the radiates Thomson and Henderson (1906) described the sclerites to be straight and curved spindles, up to 0.4 mm long. From our material and findings of Prof. Y. Benayahu (see Alderslade 2000: 246) it seems only one Briareum species is present in the Red Sea and the western Indian Ocean. Consequently, the correct name should be the oldest available, Briareum punctatum May, 1898, but the type material of Briareum punctatum is missing. As we had no material from its type locality, Zanzibar, we could not designate a proper neotype yet. As the species was never again found in Zanzibar we still have some doubts about its identity and thus defer to Briareum hamrum for the moment. Notably, also the type material of Sympodium splendens , Alcyonium (Erythropodium) contortum and Briareum hamrum seems to be missing.

This is the first record of a Briareum species from the Persian Gulf, and Oman Sea (see Samimi-Namin and van Ofwegen 2009, 2012).

Morphological variation.

RMNH Coel. 41407 (Figure 2F) from the Persian Gulf differs from the above described Red Sea specimen. It has longer sclerites (up to 0.40 mm long; Figure 9B) and more slender interior branched bodies (Figure 9C). RMNH Coel. 41410 (Figure 11A) from Oman has even longer sclerites than the Persian Gulf specimen (up to 0.45 mm long; Figure 10); it is the only specimen having long calyces. RMNH Coel. 41409 (Figure 11B), also from Oman, has sclerites (Figure 9 D–F) with the same size as the Red Sea specimen, but the slender interior branched bodies as the Persian Gulf and other Oman specimen. RMNH Coel. 41412 has completely colourless sclerites, however, the colour of live specimens was similar to others. The shape of the colonies in the examined material showed variation, from completely encrusting to somewhat having branches and an undulated surface.

Colour.

The living colonies were cream with magenta tints in some parts of the colony. Polyps were dark green to brown, brown pinnules, white oral disk and white line that continues along the tentacles (Figure 26 A–B)

Distribution.

Red Sea, East Africa, Oman Sea, Arabian Sea, Persian Gulf.