Ovabunda impulsatilla (Verseveldt & Cohen, 1971)

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 : 24-28

Ovabunda impulsatilla (Verseveldt & Cohen, 1971) Figs 14 ,15 ,16

Xenia impulsatilla Verseveldt & Cohen, 1971: 59-60, table 1; Verseveldt 1974: 2 listed only; Benayahu 1990, listed only; Reinicke 1997: 32, plate 19.

Xenia miniata Reinicke, 1997: 39-40 figs 17a-b, plate 24, syn. n.

Ovabunda aldersladei Janes, 2008: 613-614, figs 9-10, syn. n.

Ovabunda impulsatilla ; Janes 2008: 611-613, fig. 8; Aharonovich and Benayahu 2011.

Material.

Holotype: HUJ I Co. 84 northern Red Sea, Gulf of Aqaba, near Solar Pond (Sinai), (29°25'44.43"N, 34°49'50.31"E), 2 m, 15 August 1969, Coll. Y. Cohen. Eight colonies on a sponge, one of them is the holotype. Additional material: the holotype of Xenia miniata : RMNH Coel. 23514, Sudanese Red Sea, Sanganeb Atoll, 20 km off Port Sudan, W-slope, TQ IV, (19°21'33.81"N, 37°19'37.66"E), 12 m, March 1991; paratypes of Xenia miniata : RMNH Coel 25412, RMNH Coel 25413, details as above, RMNH Coel. 25411, same location, SW-corner slope, TQ I, 12 m, March 1991, coll. G. B. Reinicke; RMNH Coel. 6848, northern Red Sea, gulf of Suez, El Tur (28°14'10.99"N, 33°36'51.06"E), 6 July 1969, coll. L. Fishelson; RMNH Coel. 6847, same details; RMNH Coel. 8938, same details, Abu Durbah (28°28'27.56"N, 33°19'30.13"E); the holotype of Ovabunda aldersladei RMNH Coel. 38681, Indian Ocean, Seychelles, northern coast of Bird Island (03°42'S, 55°12'E), <30 m, 21 December 1992, Tyro expedition; type of Xenia ternatana SMF 43, Indonesia, Ternate island, 1894, coll. Kükenthal; type of Xenia garciae BML 1921.11.18.1, Indian Ocean, Chagos Archipelago, coll. Diego Garcia; RMNH Coel. 8938 Red Sea, Gulf of Suez, Abu Zanima; RMNH Coel. 6847, Red Sea, Gulf of Suez, El Tur, 6 July 1969, coll. L. Fishelson; RMNH Coel. 6848, same location, misidentified as Xenia miniata

Description.

The now dry holotype is 18 mm high. The stalk is divided into two branches, 10 and 8 mm long, 6 and 4 mm wide at the base, and 8 and 4 mm wide at the uppermost part, respectively. Polyp’s body is up to 2-2.5 mm long, and tentacles up to 1.5-2 mm, featuring two rows of pinnules on each side, with 8-11 pinnules in the outermost row. The sclerites are Ovabunda -type ( Fig. 14a ) and are almost evenly distributed in all parts of the colony, measuring 0.013-0.028 × 0.019-0.039 mm in diameter (n = 36 sclerites). Occasionally, two sclerites are fused, measuring up to 0.045 mm in maximal diameter ( Fig. 14b ). The original description stated that polyp pulsation in this species occurs in live colonies. The ethanol-preserved colony is light brown.

Remarks.

At the time of examination the type was dry and, therefore, the dimensions of the pinnules are lacking and the current measurements do not reflect the original ones given by Verseveldt and Cohen (1971), who stated that "The colonies are 8-15 mm high and 10-15 mm wide. Three to four branches arise from a short stem 1-2 mm high. These branches, 2-3 mm high and 3-4 mm wide... The anthocodiae are 2 mm high and 1.2 mm wide, and tentacles are up to 2 mm long". We encountered three colonies, one with a branched stalk and two with undivided stalks. It is possible that they originally belonged to a colony that disintegrated. The current findings in general agree with the original description, although the maximal diameter of sclerites noted in the original description is larger than our findings (0.030 vs. 0.044 mm, respectively). A colony from the Seychelles was also assigned to Ovabunda impulsatilla by Janes (2008). The SEM micrographs of the holotype sclerites given by Aharonovich and Benayahu (2011), along with the current ones ( Fig. 14 ), confirm that the species should be assigned to the genus Ovabunda .

The holotype of Xenia miniata (RMNH Coel. 23514) features two rows of pinnules on each side of the tentacles, with 8-13 pinnules in the outermost row. The sclerites are Ovabunda -type, some regular ( Fig. 15a ), some pear-shaped ( Fig. 15b ) measuring 0.017-0.034 × 0.022-0.053 mm in diameter (n = 30 sclerites). Occasionally, two sclerites are fused, reaching 0.059 mm in maximal diameter ( Fig. 15c ). The paratypes of that species (RMNH 25411, 25412, 25413) feature tentacles with two rows, 11-13 pinnules in the outermost row and Ovabunda -type of sclerites, measuring 0.018-0.030 × 0.024-0.034 mm in diameter (n = 24 sclerites). Although the original description of Xenia miniata indicated three rows of pinnules in the holotype and paratypes, we found only two rows. The original description of the species indicated non-pulsating polyps in live colonies. Colour of the ethanol preserved colony is beige. Consequently, we conclude that Xenia miniata should be synonymised with Ovabunda impulsatilla .

We also examined additional colonies that were identified by Reinicke (1997) as Xenia miniata . Specimen RMNH Coel. 6848 has two rows of pinnules, with 12-14 pinnules in the outermost row; its sclerites are Ovabunda -type, reaching up to 0.051 mm in maximal diameter. Based on sclerite size, number of pinnule rows and number of pinnules in the outermost row, this specimen should be reassigned to Ovabunda biseriata . Specimen RMNH Coel. 6847 has two rows of pinnules, with 10-11 pinnules in the outermost row; and its sclerites are also of the Ovabunda -type, reaching up to 0.045 mm in maximal diameter. RMNH Coel. 8938 has two rows of pinnules, but with only 8-9 in the outermost row; its sclerites are Ovabunda -type, reaching up to 0.047 mm in maximal diameter. Based on the number of rows of pinnules on the tentacles, the number of pinnules in the outermost row, and the size and microstructure of sclerites, the latter two colonies also belong to Ovabunda impulsatilla .

Our measurements of the dimensions of the holotype of Ovabunda aldersladei (RMNH Coel. 38681) agree with those of the original description. It features 3 mm long polyp’s body, 2 mm long tentacles, with two rows of pinnules on each side, and 8-12 pinnules in the outermost row. The densely set pinnules are up to 0.6 mm long and 0.2-0.3 mm wide and with almost no gap between adjacent pinnules. The sclerites are Ovabunda -type spheroids ( Fig. 16 ), measuring 0.012-0.030 × 0.018-0.042 mm in diameter (n = 46 sclerites). Janes (2008) did not mention polyp pulsation for that species. The ethanol-preserved colony is light beige. The features of the holotype match the original description of Ovabunda aldersladei , except for sclerite size, which was found to be larger in our examination (up to 0.042 mm vs. up to 0.026 mm). The sclerites are indeed Ovabunda -type ( Fig. 16 ), similar to those depicted by Janes (2008: fig. 10). Based on similarity between Ovabunda aldersladei and Ovabunda impulsatilla in number of rows (two in both), number of pinnules in the outermost row (8-12 and 8-11, respectively), and the size and microstructure of the sclerites it is concluded that the junior species Ovabunda aldersladei should be synonymized with Ovabunda impulsatilla , giving priority to the latter.

Reinicke (1997) noted under the description of Xenia miniata n.sp. (p. 39): " Xenia ternatana Schenk, 1896; Cohn 1908: 238 (ZMB 4991)" as well as: "nec Xenia ternatana ; Kükenthal 1913: 8 (partim, NHMW C.16618)". These two colonies were not examined in the current study. However, the type of Xenia ternatana was examined (see Table 1 ) and found to have Xenia type sclerites. Moreover, Reinicke 1997 noted: " Xenia garciae ; Verseveldt 1970: 210 (RMNH Coel. 6846-6848); Verseveldt 1974: 2 (RMNH Coel. 8934, 8935, 8938); Reinicke 1995: 37, Fig. 30". Several of the above mentioned colonies were found to be Ovabunda impulsatilla (see above), whereas the type of Xenia garciae presents Xenia type sclerites and thus is not a synonym of Ovabunda impulsatilla .

Similar species.

Ovabunda impulsatilla is most similar to Ovabunda biseriata . Although they both have two rows of pinnules and non-pulsating polyps in living colonies, the numbers of pinnules in the outermost row ranges from 8-11 in Ovabunda impulsatilla and 13-16 in Ovabunda biseriata .

Distribution. Red Sea: Egypt, Sudan; Seychelles.

Figures

Figure 14. Scanning electron micrographs of polyp sclerites of Ovabunda impulsatilla (Verseveldt & Cohen, 1971) holotype (HUJ I Co. 84). a Regular sclerites b Fused sclerites. Scale bar 10 µm.

Figure 15. Scanning electron micrographs of polyp sclerites of Xenia miniata Reinicke, 1997 holotype (RMNH Coel. 23514). a Regular sclerites b Pear-shaped sclerite c Fused sclerites. Scale bar 10 µm.

Figure 16. Scanning electron micrographs of polyp sclerites of Ovabunda aldersladei Janes, 2008 holotype (RMNH Coel. 38681). Arrow indicates surface crest. Scale bar 10 µm.