Ovabunda arabica (Reinicke, 1995)

Halasz, Anna, McFadden, Catherine S., Aharonovich, Dafna, Toonen, Robert & Benayahu, Yehuda, 2014, A revision of the octocoral genus Ovabunda Alderslade, 2001 (Anthozoa, Octocorallia, Xeniidae), ZooKeys 373, pp. 1-41 : 9-12

Ovabunda arabica (Reinicke, 1995) Figs 4 ,5

Xenia arabica Reinicke, 1995: 37, figs 47-49; 1997: 36, fig. 14.

Ovabunda arabica ; Alderslade 2001: 51.

Xenia crista Reinicke, 1997: 38, figs 16a-b, plate 23, syn. n.

Material.

Holotype: RMNH Coel. 18673, northern Red Sea, Gulf of Aqaba, Saudi Arabian border bay, 20 km South of Aqaba (29°21'37.31"N, 34°57'39.48"E), 15 m, 12 November 1991, coll. G. B. Reinicke. Paratypes: RMNH Coel. 18675, northern Red Sea, Gulf of Aqaba, Nature Reserve (Aqaba), Marine science station (MSS), 10 km South of Aqaba (29°27'27.33"N, 34°58'24.19"E), 15 m, 4 November 1991, coll. G. B. Reinicke; RMNH Coel. 18676, location as above, 12 m, 5 November 1991, coll. G. B. Reinicke; additional material: holotype of Xenia crista RMNH Coel. 18677, northern Red Sea, Gulf of Aqaba, Nature Reserve (Aqaba), Marine science station (MSS), 10 km South of Aqaba (29°27'27.33"N, 34°58'24.19"E), 12 m, October 1989, coll. G. B. Reinicke; paratype of Xenia crista RMNH Coel. 18678, location as above, 15 m, October 1990, coll. G. B. Reinicke.

Description.

The holotype is 45 mm high; its stalk is 15 mm long, 7 mm wide at its base and 7 mm wide at its upper part. The polyp’s body is 12 mm long, and tentacles up to 11 mm long. The pinnules are 2 mm long and 0.2 mm wide at the base; the gap between adjacent pinnules is one pinnule wide. There are two rows of pinnules on each side and 24-25 pinnules in the outermost row. The sclerites are spheroids of the Ovabunda -type, measuring 0.028-0.036 mm at largest diameter.

One paratype (RMNH Coel. 18675) has a total height of 20 mm; its stalk is 16 mm long, 10 mm wide at the base, and 18 mm wide at its uppermost part. The polyp’s body is 9 mm long; the tentacles are 6 mm long, featuring two rows of pinnules 2.2 mm long and 0.2 mm wide on each side, and 24-29 pinnules in the outermost row. The pinnules mostly feature a one pinnule width gap. Sclerites are Ovabunda -type, regular and pear- shaped ( Fig. 4a, c ), measuring 0.016-0.030 × 0.022-0.038 mm in diameter (n = 27 sclerites). Occasionally, two sclerites are fused ( Fig. 4b ), measuring up to 0.048 mm in diameter. The sclerites are more abundant on the aboral side of the tentacles than the oral one. The second paratype (RMNH Coel. 18676) has 2 rows of pinnules on each side of the tentacles, 24-27 in the outermost row. The sclerites are Ovabunda -type, measuring 0.026-0.036 mm at maximal diameter. The original description indicated non-pulsating polyps for live colonies. Colour of the ethanol-preserved holotype is light brown.

Remarks.

The number of rows of pinnules and pinnules in the outermost row correspond to the original description of the holotype and paratypes of Xenia arabica . Their sclerites are Ovabunda -type ( Fig. 4 ) and, therefore, the species should be reassigned to that genus. Sclerite sizes given for the holotype and paratype in the original description exceed those obtained by us, as follows: holotype 0.043-0.053 mm vs. 0.028-0.036 mm at the larger diameter, and paratypes (RMNH Coel. 18675) 0.039 × 0.043 vs. 0.016-0.030 × 0.022-0.038 mm and (RMNH Coel. 18676) 0.043 × 0.051 vs. 0.026-0.036 mm, respectively. The larger size of 0.053 and 0.051 mm indicated by Reinicke (1997) falls within that of other Ovabunda species, such as Ovabunda crenata for the fused sclerites and Ovabunda gohari for larger and rare individual sclerites.

The holotype of Xenia crista (RMNH Coel. 18677) is 50 mm high and its stalk is 27 mm long, split into two branches 17 mm above its base. The branches are 10 mm long and 8 mm wide at their base and uppermost part. The polyp’s body is up to 10 mm long. The tentacles are up to 10 mm long; pinnules up to 1.5-2 mm long and 0.2 mm wide, featuring one pinnule-width gap between adjacent pinnules. The tentacles have two rows of pinnules on each side, with 22-30 pinnules in the outermost row. Sclerites are Ovabunda -type ( Fig. 5a ), measuring 0.014-0.030 × 0.017-0.037 mm in diameter (n = 48 sclerites). Occasionally, two sclerites are fused, reaching a maximal diameter of 0.042 mm ( Fig. 5b, c ).

The paratype of Xenia crista (RMNH Coel. 18678) features tentacles with two rows of pinnules and 26-29 pinnules in the outermost row. The sclerites are Ovabunda -type, 0.025-0.036 mm in maximal diameter. The original description of the species indicated non-pulsating polyps in live colonies.

Conclusions.

Both the original description of Xenia crista and the current examination revealed two rows of pinnules; however, we found 22-30 pinnules in the holotype and 26-29 in the paratypes, compared to 29-33 and 28-32, respectively, in the original description. The taxonomic features of Xenia crista overlap those of Ovabunda arabica and, therefore, they should be considered as synonyms, giving an alphabetical priority to Ovabunda arabica .

Similar species.

Ovabunda arabica is most similar to Ovabunda faraunensis . Although they both have two rows of pinnules and both have non-pulsating polyps in living colonies, the number of pinnules in the outermost row ranges from 24-29 in Ovabunda arabica compared to 17-24 in Ovabunda faraunensis .

Distribution.

Red Sea: Gulf of Aqaba.

Figures

Figure 4. Scanning electron micrographs of polyp sclerites of Ovabunda arabica (Reinicke, 1995) paratype (RMNH Coel. 18675). a Regular sclerites b Fused sclerites c Pear-shaped sclerite. Arrow indicates surface irregularity, might represent the fusion area of two individual sclerites. Scale bar 10 µm.

Figure 5. Scanning electron micrographs of polyp sclerites of Xenia crista Reinicke, 1997 holotype (RMNH 18677). a Regular sclerites b-c Fused sclerites d White rectangle in c indicates magnified area. Scale bar 10 µm.