Colonies are small and soft with cylindrical stalks, undivided or branched, terminating in one or more domed polyp-bearing regions. Polyps are not retractile and are always monomorphic. Sclerites are oval spheroids, usually abundant in all parts of the colony, mostly up to 0.035 mm in maximal diameter, and comprised of a mass of minute corpuscle-shaped microscleres.

Holotype: RMNH Coel. 23539, Sudanese Red Sea, Sanganeb Atoll, 20 km off Port Sudan, southern-slope near jetty (19°21'33.81"N, 37°19'37.66"E), 6 m, April 1991, coll. G. B. Reinicke; paratype: RMNH Coel. 23540, same location, 5 m S- jetty, October 1992, coll. G. B. Reinicke; additional material: RMNH Coel. 23535, Red Sea, Gulf of Aqaba, Aqaba, Saudi Arabian border Bay (29°21'37.31"N, 34°57'39.48"E), October 1989, coll. G. B. Reinicke; NHMW 2250, Saudi Arabia; holotype of Xenia crassa SMF 39, Indonesia, Ternate island, 1894, coll. Kükenthal; holotype of Xenia ternatana SMF 43, Indonesia, Ternate island, 1894, coll. Kükenthal.

The holotype is 45 mm high; its stalk is 15 mm long and splits at the base into three branches, two of which split again into two, 22 and 18 mm above the colony base; the latter branches are 35 and 30 mm long, 8 and 10 mm wide at their base, 4 and 6 mm wide at their uppermost part, respectively. The third branch splits 20 mm above the base into three branches, and is 40 mm long and 7 mm wide at its base and 5-7 mm wide at the uppermost part. The polyp’s body is up to 10 mm long, and the tentacles are up to 5 mm long, featuring three rows of pinnules on each side. The pinnules are relatively slender, up to 1 mm long and 0.08 mm wide, 17-20 in the outermost row with a space of one to two pinnule widths between adjacent pinnules. The spheroidal sclerites, typical regular Ovabunda sclerites, are scarce in all parts of the colony, measuring 0.011–0.030 × 0.018–0.042 mm in diameter (n = 25), composed of a mass of corpuscle-shaped microscleres. The original description indicated non-pulsating polyps for the live colonies. The ethanol-preserved holotype is light yellowish-beige, almost transparent.

The paratype is 20 mm long; its stalk is 15 mm wide at its base, splitting into two branches, each 5 mm long and 10 and 8 mm wide at the base. The polyp’s body is up to 5 mm long, and the tentacles up to 5 mm long, bearing three rows of pinnules and 15–17 pinnules in the outermost row. The pinnules are 1.6 mm long and 0.16 mm wide, with a gap between adjacent pinnules ranging from one to three pinnule widths. The sclerites are Ovabunda vabunda-type, regular or irregular in shape (Fig. 3a, c), 0.012–0.026 × 0.02–0.04 mm in diameter (n = 21 sclerites). When two sclerites fuse they reach 0.039 mm in maximum diameter (Fig. 3b). The original description indicated non-pulsating polyps for live colonies. The ethanol-preserved colony is light beige.

RMNH Coel. 23535 features polyps with three rows of pinnules on each side of the tentacles and 16–19 pinnules in the outermost row. The sclerites are Ovabunda-type, measuring 0.016–0.026 × 0.022–0.030 mm in diameter (n =13).

Reinicke (1997) noted under the species Xenia ainex n.sp. (p. 44): “nec Xenia ternatana; Kükenthal 1913: 8 (partim. NHMW 2250)” and “Xenia crassa; Reinicke 1995: 43, Fig. 32”. The description of Xenia ternatana given by Kükenthal (1913) indicated two rows of pinnules, with 18 pinnules on average, and sclerites measuring 0.017 mm in diameter, thus differing from the features of Ovabunda ainex (see above). The NHMW 2250 specimen of Xenia ternatana was examined and found to match Ovabunda ainex, as stated by Reinicke (1997). Xenia crassa was suggested to be a synonym of Ovabunda ainex (Reinicke 1997). The current examination of the types of Xenia crassa and Xenia ternatana indicates that their sclerites distinctly differ from those of Ovabunda ainex, and thus those species’ original generic assignment should be retained.

Our findings confirm the original description of Reinicke (1997) of Ovabunda ainex, but the structure of its sclerites justifies the generic re-assignment of the species to Ovabunda.

Ovabunda ainex is most similar to Ovabunda macrospiculata. Although they both have three rows of pinnules, the number of pinnules in the outermost row ranges from 15–20 in Ovabunda ainex compared to 14–18 in Ovabunda macrospiculata. The major difference between them, however, is that Ovabunda macrospiculata has pulsating polyps in live colonies and Ovabunda ainex does not.

Red Sea: Gulf of Aqaba, Sudan.

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.

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.

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.

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.

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.

Red Sea: Gulf of Aqaba.

Holotype and two paratypes(the holotype is the largest colony): RMNH Coel. 19664, northern Red Sea, Gulf of Aqaba, Saudi Arabian border bay, 20 km south to Aqaba (29°21'37.31"N, 34°57'39.48"E), 21 m, 3 October 1989, coll. G. B. Reinicke; additional material: ZMTAU Co 26043, northern Red Sea, Gulf of Suez, Shag Rock (27°47'13.59"N, 34°0'22.61"E), 14 July 1987, coll. Y. Benayahu; ZMTAU Co 26044, northern Red Sea, Gulf of Suez, Southern tip of Sinai, Shaab el Utaf (27°45'9.00"N, 34°10'18.00"E), 10 m, 8 July 1986, coll. Y. Benayahu.

The holotype is 25 mm high; stalk is 10 mm long, 6 mm wide at colony-base, and 15 mm wide at the uppermost part. The polyp’s body is up to 4 mm long, and the tentacles up to 4 mm long, featuring a single row of 6–7 pinnules along each edge. The pinnules are short, up to 0.7 mm long and 0.4 mm wide with a 0.2–0.3 mm gap between adjacent pinnules. The sclerites are Ovabunda-type spheroids (Fig. 6a) and measure 0.019–0.035 × 0.027–0.041 mm in diameter (n = 22 sclerites). When two sclerites are fused they measure up to 0.043 mm in maximal diameter (Fig. 6b). The original description indicated non-pulsating polyps in live colonies. The ethanol-preserved colony is light brown-beige.

ZMTAU Co 26043, originally identified by Benayahu (1990) as Xenia nana, comprises 13 colonies up to 17 mm in height. Their stalks are not divided, and are up to 8 mm long, 8 mm wide at the base, and 10 mm wide at the uppermost part. Polyp’s body reaches up to 1.4 mm in length, tentacles up to 1.6 mm, featuring a row of 5–6 closely set pinnules, 0.4 mm long and 0.16 mm wide. Sclerites are Ovabunda-type spheroids (Fig. 7a), 0.016–0.029 × 0.020–0.039 mm in diameter (n = 34 sclerites); some are egg-shaped (Fig. 7c) and sometimes two spheroids are fused (Fig. 7b). ZMTAU Co 26044 comprises several disintegrated small colonies, similar in size to those of ZMTAU Co 26043. There are 5–7 pinnules in a single row on each side of the tentacles. The sclerites are Ovabunda-type, 0.015–0.031 × 0.022–0.039 mm in diameter (n = 34 sclerites). Polyp pulsation was not noted by Benayahu (1990). The colonies (ZMTAU Co 26043–26044) were misidentified as Xenia nana by Benayahu (1990) and should be reassigned to Ovabunda benayahui. The type of Xenia nana (BML 1939.6.12.9) was examined by the last author of the current paper and found to be of the genus Aldersladum Benayahu & McFadden, 2011.

The features of the holotype and paratypes of Ovabunda benayahui agree with the original description of the species, and the assignment to Ovabunda by Alderslade (2001) was confirmed in the current study.

Ovabunda benayahui is most similar to Ovabunda verseveldti. Although they both have one row of pinnules, the numbers of pinnules in the outermost row ranges from 6–7 in Ovabunda benayahui compared to 12–18 in Ovabunda verseveldti.

Red Sea: Gulf of Aqaba, Southern tip of Sinai Peninsula; Seychelles (see Janes 2008).

Holotype and five paratypes: HUJ I Co. 72, northern Red Sea, Gulf of Aqaba, Marsa Murach (29°25'34.44"N, 34°50'10.46"E), 1–4 m, 15 September 1969, coll. Y. Cohen; holotype of Ovabunda obscuronata HUJ I Co. 120, northern Red Sea, Gulf of Aqaba, Ras el Muqebla (29°24'1.20"N, 34°48'41.99"E), 12 m, 16 August 1971, coll. Y. Cohen; holotype of Xenia ternatana SMF 43, Indonesia, Ternate island, 1894, coll. Kükenthal.

The holotype is 28 mm high, stalk is 15 mm long, 11 mm wide at its base and 10 mm wide at the uppermost part; it is attached to the skeleton of a stony coral. Polyp’s body reaches up to 8–10 mm, and the tentacles 6–7 mm, bearing pinnules up to 1 mm long and 0.24 mm wide, separated by less than a pinnule-width. Two rows of pinnules are aligned along each of the tentacles margins, with 13–15 pinnules in the outermost row. There are numerous sclerites, abundant in all parts of the colony except for the mid-line of the oral side of the tentacles, where they are scarce. The sclerites are Ovabunda-type (Fig. 8), measuring 0.013–0.029 × 0.018–0.039 mm in diameter (n = 100 sclerites). Rarely, two sclerites are fused, reaching a maximum diameter of 0.048 mm and occasionally 0.060 mm. The paratypes are of similar size to the holotype, featuring tentacles with two rows of pinnules and 13–16 pinnules in the outermost row. The stalk of the smallest paratype is divided into two branches; the paratype tentacles bear two rows of pinnules with 10–12 pinnules in the outermost row. The sclerites of all paratype colonies are Ovabunda-type, ranging 0.018–0.025 × 0.023–0.039 mm in diameter. The original description of the species indicated non-pulsating polyps in live colonies. The preserved colonies are yellowish-light beige in colour.

In general the original description of the species corresponds to the current findings. SEM micrographs of the holotype sclerites (Fig. 8) indicate that they are indeed Ovabunda-type, and therefore further confirm the previous assignment to that genus (Alderslade 2001; Aharonovich and Benayahu 2011). The number of rows of pinnules, the number of pinnules in the outermost row, and the dimensions of the holotype colony of Ovabunda obscuronata (HUJ I Co. 120) correspond to the original description by Verseveldt and Cohen (1971). The sclerites are oval spheroids, Ovabunda-type, ranging 0.012–0.026 × 0.018–0.041 mm in diameter (Fig. 9, n = 61 sclerites). Rarely, two sclerites are fused, reaching a maximal diameter of 0.060 mm. The original description indicated a maximum diameter of 0.045 mm for the stalk sclerites, 0.060 mm for those of the anthocodiae and “irregular spicules” in the tentacles (Verseveldt and Cohen 1971: 60). The latter probably referred to fused sclerites, which were not identifiable under light microscopy. The original description of Ovabunda obscuronata indicated non-pulsating polyps in live colonies, similar to Ovabunda biseriata. The ethanol-preserved holotype is light brown in colour.

Reinicke (1997) noted under the description of Xenia obscuronata (p. 33): “nec Xenia ternatana; Kükenthal 1913: 8 (in part)”. The type of Xenia ternatana was examined during the present study and its features do not agree with those of Ovabunda obscuronata. Xenia ternatana features platelets composed of dendritic rods, measuring up to 0.022 mm in maximal diameter. It should be noted that the description of Xenia ternatana by Kükenthal also does not correspond to the features of Ovabunda obscuronata.

Examination of the holotype of Ovabunda biseriata and Ovabunda obscuronata revealed certain similarities, as already noted in the original description (Verseveldt and Cohen 1971): two rows of pinnules, with 12–15 vs. 14–16 pinnules, respectively, in the outermost row. The original description noted differences in the size of sclerites; 0.018–0.035 mm in Ovabunda biseriata vs. 0.045 mm in the stalk and anthocodiae and 0.060 mm in the tentacles of Ovabunda obscuronata. The current examination revealed a similar size range in the two species (0.013–0.029 × 0.018–0.039 vs. 0.012–0.026 × 0.018–0.041, respectively). Therefore, it is concluded that Ovabunda biseriata and Ovabunda obscuronata are in fact synonyms, giving alphabetical priority to the former.

Ovabunda biseriata is most similar to Ovabunda impulsatilla and Ovabunda faraunensis. Although they all have two rows of pinnules and non-pulsating polyps in living colonies, the number of pinnules in the outermost row ranges from 13–16 in Ovabunda biseriata compared to 8–11 in Ovabunda impulsatilla and 17–24 in Ovabunda faraunensis.

Red Sea: Gulf of Aqaba, Gulf of Suez, Sudan.

Holotype: RMNH Coel. 23538, Sudanese Red Sea, Sanganeb Atoll, 20 km off Port Sudan, S-slope near jetty (19°21'33.81"N, 37°19'37.66"E), 10 m, April 1991, coll. G.B. Reinicke; additional material: RMNH Coel. 23517, Sudanese Red Sea, Sanganeb Atoll, lagoon slope, TQ II station, 8 m, March 1991, coll. G.B. Reinicke; type of Xenia viridis SMF 42, Indonesia, Ternate island, 1894, coll. Kükenthal; type of Xenia blumi SMF 44, Indonesia, Ternate island, 1894, coll. Kükenthal.

The holotype is 30 mm high and 10 mm wide at its base. The stalk splits into two branches. The first is 15 mm long, 6 mm wide at its base and 10 mm wide at its uppermost part; the second splits further into two branches, 15 and 7 mm long, each 5 mm wide at the base, and 10 and 7 mm wide at the upper part, respectively. Polyp’s body is up to 5 mm long and the tentacles up to 5 mm long. The pinnules are mostly arranged in two rows, with an occasional third row. There are 12–16 pinnules in the outermost row, 1 mm long and 0.14 mm wide, with a 0.2 mm space between adjacent pinnules. Sclerites are very scarce in all parts of the holotype; they are Ovabunda-type spheroids, measuring 0.012–0.028 × 0.018–0.036 mm in diameter (n = 35 sclerites). Occasionally, two sclerites are fused, reaching 0.050 mm in maximal diameter. SEM micrographs of sclerites were obtained only from the additional material due to low density of sclerites in the holotype. Reinicke (1997) recorded non-pulsating polyps for the species. The ethanol preserved holotype is light beige.

RMNH Coel. 23517 is similar in size to the holotype. Polyp’s body is up to 2 mm long, with 2 mm long tentacles, mostly bearing two rows of 1 mm long and 0.1 mm wide slender pinnules on each of the tentacle sides, and, rarely, a third row. The outermost row features 12–15 pinnules, up to one pinnule-width apart. Sclerites are of the Ovabunda-type, varying in shape from regular (Fig. 10a), egg-shaped (Fig. 10c) and more rectangular (Fig. 10d), ranging 0.016–0.026 × 0.028–0.040 mm (n = 25 sclerites) in diameter. Occasionally, two sclerites are fused, reaching 0.047 mm in maximal diameter (Fig. 10b).

Reinicke (1997) noted under the description of Xenia crenata sp. n. (p. 41): “?Xenia blumi Schenk 1896; Gohar 1940: 98, Plate 5” and “Xenia blumi Schenk 1896 sensu Gohar – Reinicke 1995: 42, Fig. 31”. Reinicke (1997) also noted: “?Xenia viridis Schenk 1896; Benayahu 1990: 115 (listed)”. The description of Xenia blumi according to Gohar (1940) does not match Ovabunda crenata features. Examination of the types of Xenia blumi and Xenia viridis during the current study (see Table 1) revealed them to have platelet-shaped sclerites composed of dendritic rods, and to differ from Ovabunda crenata.

The original description of the holotype indicated three rows of pinnules, whereas the present examination revealed mostly two rows, with an indication of a third one. There is agreement between our findings and the original description regarding the number of pinnules in the outermost row of the tentacles (12–16 vs. 12–15, respectively). Sclerites correspond to the original description in size but are Ovabunda-type spheroids; therefore, it is concluded that the species should be assigned to Ovabunda.

Ovabunda crenata is most similar to Ovabunda biseriata. Although they both have overlapping number of pinnules in the outermost row, 12–16 and 13–16, respectively, Ovabunda biseriata has two rows of pinnules and Ovabunda crenata occasionally presents a third row. They both have non-pulsating polyps in live colonies.

Red Sea: Gulf of Aqaba, Sudan.

Holotype: HUJ I. Co. 140, northern Red Sea, Gulf of Aqaba, opposite Gezirat Fara’un (Coral Island) (29°27'46.95"N, 34°51'27.38"E), 18 m, 15 October 1969, coll. Y. Cohen.

The holotype is 16 mm high; its stalk is 6-10 mm long, 4 mm wide at the base and 7 mm wide at its uppermost part. Polyp’s body is up to 2-4 mm long and the tentacles 3-5 mm long, featuring two rows of pinnules on each side with 17-24 pinnules in the outermost row. The sclerites are Ovabunda-type spheroids (Fig. 11a), measuring 0.013–0.028 × 0.019–0.033 mm in diameter (n = 46 sclerites). Occasionally, two sclerites are fused, reaching up to 0.044 mm in maximal diameter (Fig. 11b). Verseveldt and Cohen (1971) recorded non-pulsating polyps for this species. Colour of the ethanol-preserved holotype is beige.

At the time of examination the holotype was dry, and therefore precise dimensions of the pinnules could not be obtained. The original description (Verseveldt and Cohen 1971: 62) indicated that: “The colony is 25 mm high. The stem is 15 mm high and 5–6 mm wide at the base, then narrows to 3–4 mm and widens again to 7 mm or more at the beginning of the polyparium. The anthocodiae are up to 10 mm long... the tentacles are 5–6.5 mm long”. It is evident that the dimensions of the dried holotype are smaller than those of the original. The other features of the holotype recorded correspond to the original description, including two rows of pinnules, 17–24 pinnules in the outermost row, and sclerite diameter up to 0.044 mm (vs. 17–23 and 0.042 mm, in the original description). Reinicke (1997) presented a SEM micrograph of a single sclerite of Ovabunda faraunensis which later led Alderslade (2001) to assign it to the genus Ovabunda.

The current examination of the holotype (Fig. 11) along with the examination of the holotype by Aharonovich and Benayahu (2011), further confirmed the previous assignment.

Ovabunda faraunensis is most similar to Ovabunda arabica. 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 17–24 in Ovabunda faraunensis compared to 24–29 in Ovabunda arabica.

Red Sea: Gulf of Aqaba, Sudan (see Reinicke 1997).

Holotype: RMNH Coel. 23435 and a paratype: RMNH Coel. 23436 northern Red Sea, Gulf of Aqaba, 10 km south to Aqaba, Nature Reserve (Agaba) (29°26'29.03"N, 34°58'0.50"E), 10 m, November 1991 and 3 December 1991, respectively; coll. G. B. Reinicke.

The holotype is 25 mm high; the stalk is 15 mm long, 10 mm wide at its base and 20 mm wide at its uppermost part and is divided into two. Polyp’s body reaches 5 mm and the 11 mm long tentacles mostly feature a single row bearing 19–22, 3 mm long and 0.2 mm wide pinnules. The gap between the pinnules is up to twice their width; occasionally a second row exists and then the outermost row bears 19–22 pinnules. The gap between adjacent pinnules in the outmost row is almost twice their width, as in the case of a single row. The sclerites are Ovabunda-type spheroids, measuring 0.028–0.045 mm in diameter (Fig. 12).

The paratype is 18 mm long. Its stalk is divided into two branches, 8 mm and 4 mm long; each branch is 3 mm wide at its base, and 5 and 4 mm wide at the uppermost part, respectively. Polyp’s body is up to 3 mm long, and tentacles 5–8 mm long, each have one row of 18–21 pinnules on each side; some small polyps have only 11–13 pinnules. The pinnules are up to 3 mm long and 0.24 mm wide at the base and the gap between the pinnules is up to twice their width. The sclerites (Fig. 12a) measure 0.015–0.035 × 0.028–0.055 mm in diameter (n = 30 sclerites). Occasionally, two sclerites are fused, measuring up to 0.060 mm in maximal diameter; the fusion of sclerites can be partial or almost complete (Fig. 12b). The sclerites are more abundant at the base of the pinnules along the tentacle midline compared to their distal part, and similarly at the aboral side of the tentacles compared to their oral side. The original description indicated non-pulsating polyps in live colonies. The ethanol-preserved colony is light yellowish, beige.

The current study confirmed the number of rows of pinnules and number of pinnules of the original description. Sclerite dimensions of the latter are larger than our findings, probably due to measurements that included fused sclerites.

The sclerites are Ovabunda-type spheroids and justify assignment to that genus.

Ovabunda gohari is most similar to Ovabunda faraunensis. Although they both have overlapping number of pinnules in the outermost row, 18–22 and 17–24, respectively, Ovabunda gohari has mostly one row of pinnules and Ovabunda faraunensis presents two rows of pinnules. They both have non-pulsating polyps in live colonies.

Red Sea: Gulf of Aqaba, Sudan (see Reinicke 1997).

Holotype: RMNH Coel. 23904, Sudanese Red Sea, Sanganeb Atoll, off Port Sudan, reef flat (19°21'33.81"N, 37°19'37.66"E), 6 April 1991, coll. G. B. Reinicke; paratypes: RMNH Coel. 23902, same data as above, April 1991; RMNH Coel. 25906, same locality SW corner, 15 m; RMNH Coel. 23553, Sudanese Red Sea, Sanganeb Atoll, lagoon slope near TQ II, 12 m, October 1992, coll. G. B. Reinicke; additional material: RMNH Coel. 23552, same locality, W-slope, TQ IV, 12 m, April 1991, coll. G. B. Reinicke; RMNH Coel. 25903, same locality, SE corner, reef flat; RMNH Coel. 25905 SW corner, 15 m; RMNH Coel. 23907, near southern jetty, 10 m; all April 1991, all coll. G. B. Reinicke; RMNH Coel. 23908, Indian Ocean, Madagascar, 1960, coll. M. Cherbounier, MNHN Oct.A.1993.16; holotype of Xenia grasshoffi SMF 2616, northern Red Sea, Gulf of Aqaba, Elat, 1 January 1968, coll. Grasshoff M.

The holotype is 25 mm high and its stalk is 18 mm long, 15 mm wide at its base and 12 mm wide at its uppermost part. Polyp’s body reaches up to 2 mm long; tentacles 5 mm long featuring three rows of 1 mm long and 0.16 mm wide pinnules, 19-21 in the outermost row. An incomplete fourth row is occasionally present. The pinnules are separated by a two-pinnule width space. The sclerites are Ovabunda-type (Fig. 13a), 0.015–0.025 × 0.016–0.035 mm in diameter (n = 25). Occasionally, two sclerites are partially fused, reaching 0.034 mm in maximal diameter (Fig. 13b). The tentacles of the paratypes (RMNH Coel. 25902, 23533, 25906) bear three rows of pinnules on each side, with 19–22, 19–21 and 17–22 pinnules in the outermost row, respectively, and all feature Ovabunda-type sclerites. The original description indicated non-pulsating polyps in live colonies. The ethanol-preserved colony is light beige.

The colonies RMNH Coel. 25905, 23907, 23908 feature three rows of pinnules with 17–22 pinnules in the outermost row. The tentacles of RMNH Coel. 23552 have four rows of pinnules and 18–21 pinnules in the outermost row; RMNH Coel. 25903 has three rows of pinnules with an indication of a fourth row, and 19–22 pinnules in the outermost row. All colonies feature Ovabunda-type sclerites.

Janes (2008) described Ovabunda hamsina from the Seychelles and the current findings confirm the assignment of Ovabunda hamsina to the genus Ovabunda based on sclerite microstructure.

Reinicke (1997) noted under the description of Xenia hamsina sp. n. (p. 49): “Xenia aff grasshoffi Reinicke, 1995: 59, Fig. 33”. The type of Xenia grasshoffi was examined by us (see Table 1), and found to have the type of sclerites found in Xenia and clearly different from Ovabunda hamsina.

Similar species. Ovabunda hamsina is most similar to Ovabunda ainex. Although they both have overlapping number of pinnules in the outermost row, 17–22 and 15–20, respectively, Ovabunda ainex has three rows of pinnules and Ovabunda hamsina presents three and sometimes four rows of pinnules. They both have non-pulsating polyps in live colonies.

Distribution. Sudanese Red Sea, Madagascar, Seychelles (see Janes 2008).

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

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 areOvabunda-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.

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.

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.

Neotype: ZMTAU Co 25635, northern Red Sea, Gulf of Suez, Shag Rock (27°47'1.48"N, 33°59'23.17"E), <5m, 11 July 1986, coll. Y. Benayahu. Paratypes: ZMTAU Co 35789 (field number A69) northern Red Sea, Gulf of Aqaba, Underwater Restaurant (29°32'49.43N, 34°57'14.51"E), 5 m, 3 May 2010, coll. A. Halász; ZMTAU Co 35790 (field number A70) northern Red Sea, Gulf of Aqaba, The Interuniversity Institute of Marine Sciences in Eilat (IUI) (29°30'6.54"N, 34°55'4.44"E), 22 m, 4 May 2010, coll. A. Halász; ZMTAU Co 35791 (field number A72), collection details as above, 9 m.

The neotype is 20 mm high. Its stalk is 10 mm wide at its base, splitting into three branches, 7, 5 and 5 mm long; 5, 4 and 4 mm wide at the base and 10, 6 and 7 mm wide at the uppermost part, respectively. Polyp’s body reaches up to 2 mm and tentacles up to 5 mm, bearing three, occasionally two, rows of pinnules. The pinnules are 1 mm long and 0.2 mm wide, with less than a pinnule-width space between them, and there are 15–17 pinnules in the outermost row on each side of the tentacle. The sclerites are Ovabunda-type, both regular and pear-shaped, measuring 0.015–0.025 × 0.023–0.041 mm (n = 34, Fig. 17a, b). Occasionally two sclerites are fused, reaching 0.041 mm in maximal diameter (Fig. 17c).

The other specimens (ZMTAU Co 35789, 35790, 35791) are of similar size to the neotype; all with three rows of pinnules aligned on both sides of the tentacles, and 14–18, 14–17 and 14–17 pinnules in the outermost row, respectively. Their sclerites are of the Ovabunda-type and vary in shapes from regular to irregular, pear-shaped or fused. Their size ranges through 0.016–0.025 × 0.023–0.043 mm; 0.014–0.03 × 0.019–0.043 mm (Fig. 18) and 0.015–0.027 × 0.022–0.046 mm (Fig. 19) in diameter, respectively (n = 21 for each colony).

Xenia macrospiculata was originally described by Gohar (1940) from Ghardaqa, Egyptian Red Sea, as having pulsating tentacles, bearing three, occasionally two, rows of pinnules, with 12–16 pinnules in the outermost row (and 10–14 pinnules on the middle row, 0–10 on the oral one). That study did not indicate the museum in which the type was deposited. The last author of the current study searched in the museums listed in the Methods and found no trace of it; over time this type was probably lost. The designation of a neotype in this revision is thus necessary. The purpose of the designation is to clarify the species’ taxonomic status and its assignment to Ovabunda. Although the sclerites were described quite accurately in the original description (0.024–0.036 mm in diameter, and “spicules fused in pairs”), SEM micrographs of the sclerites are essential as in the other species of the revision.

The neotype was collected in proximity to the collection site of the original specimen collected by Gohar. The neotype is located at ZMTAU, and available upon request for future examination.

Ovabunda macrospiculata was also described by Verseveldt (1971: 64–65, fig. 39) from Nosy Be, Madagascar, referring to three and sometimes four rows of pinnules with 12–16 pinnules in the outermost row, and sclerites 0.020–0.042 mm in maximal diameter. Examination of RMNH Coel. 6702 from that study revealed that its tentacles have mostly four, rarely three rows of pinnules, and 14–16 pinnules in the outermost row (Reinicke 2013, pers. comm.). During our study the sclerites were examined and they are indeed Ovabunda-type, measuring up to 0.043 mm in maximum diameter, while fused sclerites are 0.055 mm in diameter. Based on the number of rows of pinnules and the number of pinnules at the outermost row, we conclude that it does not agree with Ovabunda macrospiculata.

Ovabunda macrospiculata is most similar to Ovabunda ainex. Although they both have three rows of pinnules, the numbers of pinnules in the outermost row ranges from 14–18 in Ovabunda macrospiculata compared to 15–20 in Ovabunda ainex. The major difference between them is that Ovabunda macrospiculata presents pulsating polyps in live colonies and Ovabunda ainex does not.

Red Sea: Gulf of Aqaba, southern tip of Sinai Peninsula.

Holotype: ZMTAU Co 26048 and four paratypes: ZMTAU Co 31625 northern Red Sea, Gulf of Aqaba, Dahab (28°30'34.21"N, 34°31'18.26"E), 1 m, 9 November 1979, coll. Y. Benayahu.

The holotype is 18 mm high; its stalk is 9 mm long, 5 mm wide at its base and 13 mm wide at its uppermost part. Polyp’s body is 1–4 mm long, and the tentacles 6 mm long, bearing 1.8 mm long and 0.2 mm wide pinnules separated from each other by a small gap, less than one pinnule width. A single row of 14–18 pinnules is aligned on each side of the tentacles. There are numerous sclerites in all parts of the colony, densely packed in the pinnules and scarce in the mid-line of the tentacles’ oral side. The sclerites are Ovabunda-type, varying in shape from regular spheroids (Fig. 20b) to egg-shaped (Fig. 20a) and more rectangular forms (Fig. 20c), measuring 0.014–0.033 × 0.022–0.046 mm in diameter (n = 45). Rarely, two sclerites are fused, reaching a diameter of up to 0.051 mm (Fig. 20d).

The four paratypes (ZMTAU Co 31625) are smaller than the holotype, 12–17 mm high; the stalk is 10–15 mm long, 4–6 mm wide at the stalk base and 6–8 mm wide at the upper part. Polyp’s body is up to 5 mm long, and tentacles up to 3 mm long, featuring one row of 12–17 pinnules on each side. The pinnules are 1.2 mm long and 0.2 mm wide at their base, densely set in each row, almost touching each other. The sclerites are Ovabunda-type, measuring 0.018–0.030 × 0.022–0.049 mm in diameter (n = 38). Occasionally, two sclerites are fused, reaching a maximum size of 0.049 mm. The original description did not mention polyp pulsation. The ethanol-preserved colonies are light brown.

The features of the holotype and paratypes agree with the original description of the species. The species was assigned by Alderslade (2001) to Ovabunda (see Introduction) and this is confirmed in the current study.

Ovabunda verseveldti is most similar to Ovabunda benayahui. Although they both have one row of pinnules the numbers of pinnules in the outermost row ranges from 12–18 in Ovabunda verseveldti compared to 6–7 in Ovabunda benayahui.

Red Sea: Gulf of Aqaba, southern tip of Sinai Peninsula.