Conglomeratusclera coerulea (May, 1898)

Benayahu, Yehuda, Ofwegen, Leen P. van & McFadden, Catherine S., 2018, Evaluating the genus Cespitularia MilneEdwards & Haime, 1850 with descriptions of new genera of the family Xeniidae (Octocorallia, Alcyonacea), ZooKeys 754, pp. 63-101 : 65-81

Conglomeratusclera coerulea (May, 1898) Figures 1 A–B, 2, 3, 4, 5 A–B, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25

Cespitularia coerulea May, 1898: 21; May 1899: 90, plate I, fig. 10; Kükenthal 1902: 659; Thomson and Henderson 1906: 414-415; Thomson and Mackinnon 1910: 173, plate 12, fig. 5; Hickson 1931: 162 (listed only); Thomson and Dean 1931: 32-33; Roxas 1933: 106, plate 4, fig. 6; Malyutin 1992: 2 (listed only); Benayahu et al. 2004: 551 (listed only).

Cespitularia taeniata May, 1899: 89-90; Kükenthal 1902: 659, Hickson 1931: 162; Utinomi 1950: 14-15, fig 3b, c; 1954: 102 (listed only); Thomson and Mackinnon 1910: 172, Thomson and Dean 1931: 33.

Material.

Syntypes: ZANZIBAR: ZMH C 2518, Kokotoni, two colonies and two fragments, Tumbatu (southern reef), 24 July 1885, coll. Stuhlmann; ZMB Cni 3671, two colonies, 1885, coll. Sander; types of Cespitularia taeniata ; MOZAMBIQUE: ZMH C 2519, three colonies and three fragments, coll. Philippi, 1884.

Other material.

JAPAN: ZMTAU Co 29285, Yonaguni Is., Ryukyu Archipelago, coll. Y. Benayahu, 13 November 1992, ten specimens; ZMTAU Co 29290, Nurugan, Yonaguni Is., Ryukyu Archipelago, 04°05'N, 122°57'E, 23 m depth, coll. Y. Benayahu, 11 November 1992, ZMTAU Co 31699, details as before, six specimens; ZMTAU CO 35129, West Point, Yonaguni Is., Ryukyu Archipelago, 11-22 m depth, coll. Y. Benayahu, 4 July 2010, two specimens; ZMTAU CO 35130, details as before; ZMTAU Co 35131, details as before, four specimens ZMTAU Co 35132, Co 35134, Co 35138, Co 35139, details as before; ZMTAU Co 35142, West Point, Yonaguni Is., Ryukyu Archipelago, 16-22 m depth, coll. Y. Benayahu, 5 July 2010, two specimens; ZMTAU Co 35153, details as before; KENYA: ZMTAU Co 31326, Nyali, off Mombasa, 10-16 m depth, coll. Y. Benayahu & S. Perkol, 1 February 2001; ZMTAU Co 31635, Turning Bouya, Shelly Reef, off Likoni, 04°05'S, 39°41.1'E, 15-28 m depth, coll. Y. Benayahu, 27 February 2002, two specimens; MADAGASCAR: ZMTAU Co 35982, Riva Be, 12°59.126'S, 48°34.453'E, 8-10 m depth, coll. Y. Benayahu, 27 November 2012, three specimens; ZMTAU Co 35990, Riva Be, 12°59.094'S, 48°34.622'E, 10-11 m depth, coll. Y. Benayahu, 27 November 2012, two specimens; ZMTAU Co 35991, details as before, four specimens; ZMTAU Co 36013, Ankaréa, 12°50.054'S, 48°34.563'E, 6-9 m depth, coll. Y. Benayahu, 29 November 2012; ZMTAU Co 36055, Co 36063, 4 Fréres, 12°59.655'S, 48°29.248'E, 4-15 m depth, coll. Y. Benayahu, 1 December 2012; ZMTAU Co 36101, Ronald Point, Nosy Be, 13°23.530'S, 48°00.143'E, 19-27 m depth, coll. Y. Benayahu, 3 December 2012, two specimens; ZMTAU Co 36129, Ronald Point, Nosy Be, 13°29.032'S, 47°58.721'E, 2-14 m depth, coll. Y. Benayahu, 3 December 2012, two specimens; USNM 54000 Nosy Be; USNM 54003 Nosy Be; MOZAMBIQUE: ZMTAU Co 31296, Ilha Sete Paus, 14°58.572'S, 40°47.389'E, 6 m depth, coll. M. Schleyer, 16 November 2000, two specimens; ZMTAU Co 31337, Ilha Caldeira, 16°38'22"S, 39°43'10"E, 4-16 m depth, coll. M. Schleyer, 2 June 2000, four specimens; TAIWAN: ZMTAU, Co 32988, Lomen yan, Green Is., 22°40'56"N, 121°30'06"E, 3-25 m depth, coll. Y. Benayahu, 12 July 2005; ZMTAU Co 33006, details as before, seven specimens, Co 33008, details as before; ZMTAU Co 33030, Dabaisha, Green Is., 22°38'25"N, 121°29'04"E, 10-25 m depth, coll. Y. Benayahu, 14 July 2005; ZMTAU Co 33036, Co 33043, 33045, Nanliao, Green Is., 22°39'40"N, 121°27'59"E, 10-25 m depth, coll. Y. Benayahu, 14 July 2005; ZMTAU Co 35693, Co 35699, Co 35708, Co 35709, Co 35712, Co 35714, Co 35716, Co 35717, (only molecular sample), Shihlang, Green Is., 22°39.425'N, 121°28.399'E, 8-12 m depth, coll. Y. Benayahu, 3 September 2012, ZMTAU Co 35692, details as before, three specimens; ZMTAU Co 35706, Co 35707, details as before, two specimens; ZMTAU Co 35725, Dabaisha, Green Is., 22°38.284'N, 121°29.457'E, 14-25 m depth, coll. Y. Benayahu, 4 September 2012; ZMTAU Co 35729, details as before, two specimens; ZMTAU Co 35731, details as before, three specimens; ZMTAU Co 35736, Co 35737, Dabaisha, Green Is., 22°38.284'N, 121°29.457'E, 11-15 m depth, coll. Y. Benayahu, 4 September 2012; ZMTAU Co 35742, details as before, two specimens; ZMTAU Co 35747, Co 35748, Co 35750, Co 35753, Iron Artificial Reef, Green Is., 22°38'33"N, 121°28'31"E, 20-26 m depth, coll. Y. Benayahu, 5 September 2012; ZMTAU Co 35752, details as before, three specimens, ZMTAU Co 35756, Co 35758, Co 35760, Co 35763, Co 35765, Co 35774, Shihlang, Green Is., 22°39.425'N, 121°28.399'E, 7-10 m depth, coll. Y. Benayahu, 5 September 2012; ZMTAU Co 35759, details as before, two specimens; ZMTAU Co 36232, Co 36235, Shihlang, Green Is., 22°39'17.91"N, 121°28'26.41"E, 6-11 m depth, coll. Y. Benayahu, 26 August 2013; ZMTAU Co 36247, details as before, four specimens; ZMTAU Co 36255, Gueiwan, Green Is., 22°38'41"N, 121°28'26"E, 10-18 m depth, coll. Y. Benayahu, 27 August 2013, two specimens; MAYOTTE: ZMTAU Co 37403, Glorioso Is., 11°34.880'S, 47°16.862'E, 10-11.5 m depth, coll. M. Schleyer, 20 November 2016, two specimens; ZMTAU Co 37430, Saziley, 12°59.138'S, 45°10.947'E, 3-4 m depth, coll. M. Schleyer, 26 June 2011; ZMTAU Co 37431, Station East Bouzi, 12°48.739'S, 45°14.543'E, 5-10 m depth, coll. M. Schleyer, 24 June 2011; MAURITIUS: BMNH 1912.2.24.65; BMNH 1912.2.24.66; Cargados Carajos, 20-25 m depth; BMNH 1933.3.13.175, Cargados Carajos, 20-25 m depth, coll. J.A. Thomson; BMNH 1933.3.13.176, Cargados Carajos, 20-30 m depth, Percy Sladen Trust Expedition, coll. J.A. Thomson; BMNH 1933.5.3.301, Port East Africa, Sir J.A. Thomson Expedition, 11 November 1907; MALAYSIA: BMNH 1985.4.17.20, NE Borneo, Sabah, Semporna, Pulau-Pulau Mantanani. AUSTRALIA: USNM 60795, Great Barrier Reef, Myrmidon Reef, Northern Reef, 17°00'S, 146°00'E Queensland, 1982; INDONESIA: RMNH Coel 42158, SW Sulawesi, Spermonde Archipelago, west of Lumu-Lumu Is.; RMNH Coel 42159, N Sulawesi, Bunaken park, ESE Siladen Is.; RMNH Coel 42161, Snellius II Exp. Station 4.139, NE Taka Bone Rate (Tiger Is.), S. of Tarupa Kecil, edge of reef flat, 06°30'S, 121°08'E, SCUBA, snorkeling on sea grass bed, 30 m depth, 25-26 September, 13 and 17 October 1984; RMNH Coel 42162, N. Sulawesi, Selat Lembeh, Pulau Lembeh, N of Pulau Burung, 01°29'N, 125°15'E; sandy bay merging to the north in stony boulders beach, stony and soft corals, SCUBA, 22 October 1994, 2-25 m depth, coll. L.P. van Ofwegen; RMNH Coel 42163 N. Sulawesi, Selat Lembeh, Pulau Lembeh, Air Bajo, near Kereko, Nusu Dua; SUL 13, 01°29'N, 125°15'E; sandy bay between rocks, N-exposed, gently sloping bottom with large boulders, snorkeling 5 m depth, 21 October 1994, coll. J.C. Den Hartog; RMNH Coel 42165, Buginesia Prog. UNHAS-NNM, SW Sulawesi. Spermonde Archipelago N of Kudingareg Keke (=14 km WNW of Makassar), 5°06'S, 119°17'E, SCUBA, 5-25 m depth, 1994 Sul. KK SW, 14 October 1994, coll. B.W. Hoeksema; RMNH Coel 42166, Buginesia Prog. UNHAS-NNM, SW Sulawesi, Spermonde Archipelago N of Langkai Is. (=37 km WNW of Makassar), 5°02'S, 119°05'E, coral reef, SCUBA, 24 June 1994, coll. B.W. Hoeksema; RMNH Coel 42167, Buginesia Prog. UNHAS-NNM, SW Sulawesi, Spermonde Archipelago N of Langkai Is. (=37 km WNW of Makassar), 5°02'S, 119°05'E, coral reef, SCUBA, 24 June 1994, coll. B.W. Hoeksema; RMNH Coel 42170, Buginesia Prog. UNHAS-NNM, SW Sulawesi, Spermonde Archipelago, N of Kudingareng Keke (=14 km WNW of Makassar), 5°0'S, 119°17'E, SCUBA, 1994 Sul. KK SW, 5 September 1994, coll. B.W. Hoeksema; PHILIPPINES: RMNH Coel 42160, Cebu strait Expedition, Station CEB. 13.

Notes to previous description.

The original description of C. coerulea by May (1898) referred to a colony from Kokotoni, Zanzibar. Later, May (1899) repeated the description, referring to colonies collected from that location in 1889 by Stuhlmann and from Zanzibar in 1885 by Sander, deposited in Hamburg and Berlin museums, respectively. During a visit by the senior author to ZMH two colonies were found labeled as the type of C. coerulea , both collected in Kokotoni, Zanzibar, 24 July 1895 (leg. Stuhlman). Similarly, in a subsequent visit to ZMB two colonies were found, labeled as syntypes of C. coerulea , collected in Zanzibar, 1895 (leg. Sander). Both ZMH and ZMB colonies are considered to be the original syntypes of that species and are re-described below.

Description.

ZMH C 2518 consists of two colonies; the first is 8.5 cm high by 4.2 cm wide and the second 5 cm high by 4 cm wide (Figure 1A). The polypary of these colonies is branched and their tips are bent. They bear non-retractile polyps, with some occurring towards the upper part of the colony’s base. The polyp body is up to 8 mm long and the tentacles are up to 3 mm long; the latter bear one row of pinnules and 16-18 pinnules along each edge. The pinnules are short, pointed and evenly placed along the tentacle, with a narrow space of less than a pinnule width between adjacent ones. The preserved colonies are pale gray- almost white. Sclerites could not be found in the upper part of the branches or in the polyps. However, the lower part of the branches, including the base of the colonies, feature conglomerates, comprised of spherules and small dumbbell-like sclerites, mostly cemented (Figure 2). The spherules are about 0.002-0.006 mm in diameter (Figures 2A, E–G), with a rather rough surface-texture. The abundance of the dumbbells (Figures 2 B–D, F) may exceed that of the spheroids. The former vary in size, with a length of 0.003-0.006 mm. The conglomerate nature of the sclerites exhibits a large morphological variation as demonstrated in Figure 2. The syntype ZMB Cni 3671 (Figure 1B) resembles syntype ZMH 2518, except for the size of the colonies. Most of the polyps of the former are expanded, well-preserved, and thus recognizable on the branches of the colony. The sclerites are similar, conglomerated spheres and spherules along with some double-heads (Figure 3), but are less common in the tissues compared to ZMH C 2518. Under the light microscope wet preparations of the tentacles removed from ZMB Cni 3671 revealed some conglomerates along with spheres of various sizes.

The type material of Cespitularia taeniata (ZMH C 2519) comprises two flaccid colonies and two additional fragments (Figure 1C). The colonies are 3-4.5 cm high by 2-2.5 cm wide. Their polyparies consist of short branches bearing non-retractile polyps; some polyps were also found on the upper part of the stalk. The tentacles feature one row of 16-18 pointed pinnules, evenly placed along the edges with a free space between adjacent ones. Sclerites were found in the base of the colonies and the branches (Figure 4) but none in the polyps. They are conglomerates comprised mainly of spherules (Figure 4A) and some predominantly of spheres (Figure 4B), the latter measuring up to 0.018 mm in diameter. In addition, some cylinder-like small sclerites featuring round tips are also found, measuring 0.002-0.003 mm (Figure 4C). It should be noted that the aggregates tend to disintegrate during the sclerite preparation and therefore their actual dimensions cannot be determined.

A colony labeled as ZMH C 2375 (Figure 1D) features tentacles with 12-14 pinnules and sclerites similar to ZMH C 2519. ZMH C 2375 is listed in the museum’s catalog as the "Typus von Ammothea bauiana May, 1898" along with a note that Gohar had corrected the identification in 1938 to C. taeniata . Both colonies, ZMH C 2519 and ZMH C 2375, are light gray-beige. Conglomeratusclera taeniata was described by Thomson and Dean (1931: 33) as being "near to but distinct from Cespitularia coerulea ". The current findings indicate that there are only some small morphological differ ences in the colony and polyp dimensions between the two species, and therefore, the above statement appears reasonable. Utinomi (1950) described the C. taeniata specimen identified by him as having 10-12 pinnules, slightly lower in range compared to the 12-14 pinnules of C 2375. The current examination of the types of both C. coerulea and C. taeniata revealed that despite the erroneous statement that they have no sclerites, they feature quite similar sclerites. It is therefore suggested that the similarity between the two species indicates that the above-reported morphological differences in the number of pinnules of the two types represent intra-specific variation. The sequencing results obtained in the current study along with the morphological findings further substantiate this conclusion, as colonies with a single row of 8-22 pinnules share similar DNA sequences (see ahead). Therefore, it is concluded that C. coerulea and C. taeniata sensu stricto should be synonymized, and both are now designated under Conglomeratusclera coerulea .

Remarks.

The original descriptions of Cespitularia coerulea by May (1898, 1899) indicated an absence of sclerites in the colony. In contrast, the current findings dem onstrate the presence in the syntypes of a novel type of sclerite, depicted here for the first time. These sclerites are composed of agglomerated calcite-constructed minute substructures of various morphologies, mostly spherules, spheres, and double heads appearing in different arrangements. They were probably overlooked in previous stud ies due to their minute size and also occasional low abundance. Moreover, the unusual irregular sclerite morphology with almost no definite structure (Figures 2-4), may have caused the misinterpretation concerning their potential as octocoral sclerites to be used as diagnostic characters for taxonomic purposes.

Since the original description of C. coerulea a number of studies have assigned specimens to that species. Thomson and Henderson (1906) identified a multi-branched colony from Zanzibar, with one row of pinnules and no sclerites. Later, Thomson and Mackinnon (1910) described a similar colony from Cargados Carajos (Mauritius), noting that when alive the colony was "vivid grass green, but after preservation it faded to cream", a feature that has been widely observed in the current study (see below). Thomson and Dean (1931) identified C. coerulea from Kawas sang, Indonesia, obtained in the course of the Siboga Expedition, featuring a single row of pinnules and no sclerites, with no mention of the number of pinnules in the polyps. Next, Roxas (1933) identified the same species from Sabang, near Puerto Galera, Mindoro, Philippines, with one row of 14-18 pinnules and no sclerites. Interestingly, that study of Roxas’s study was the first to indicate number of the pinnules in that species. In general, the above octocoral samples are in agreement with the original description by May (1898), but all the above authors nonetheless failed to detect any sclerites.

Color.

When alive, the color of colonies ranges from vibrantly bluish-purple, light green, light yellow-beige, light cream to almost white (see Figure 5A, B). The alcohol-preserved colonies lose their vibrant colors and mostly become pale cream, gray, or beige.

Morphological variation.

In the current study, examination of the colonies from Green Is., Yonaguni Is. and Madagascar was based on both morphological characters (colony shape, pinnule count, and sclerite features), along with DNA sequencing; the latter enabled us to construct a phylogenetic tree (Figure 6). In general, the colony shape of all the colonies listed in Material Examined was in agreement with the syntypes shown above, except for colony size. All colonies exhibited one row of pinnules along the margins of the polyp tentacles, with a variable number of pinnules, ranging from 8 to 22 per row. In some colonies the tentacles were partially or completely withdrawn or the pinnules fully contracted, probably due to the preservation process. In several cases the polyps were fully expanded and in others partially or fully contracted.

The following findings denote the number of pinnules found in some of the sequenced colonies (Figure 6), demonstrating the variability in pinnule count. The respective colonies from Green Island are ZMTAU Co 35717: 8, Co 35747: 8, Co 35774: 8, Co 35742: 8-9, Co 35750: 8-9, Co 35753: 8-9, Co 35714: 10-11, Co 35712: 11-12, Co 33045: 11-16, Co 35692: 11-16, Co 35707: 11-16, Co 35699: 12-15, Co 35709: 15, Co 35758: 15, Co 35693: 15-16, Co 35729: 15-18, Co 35693: 16, Co 35725: 16-17, Co 35748: 16-18, Co 35763: 18-20, Co 35756: 20, Co 35760: 20, Co 35736: 21-22 and Co 35737: 21-22; colonies with fully contracted pinnules Co 35706, Co 35708, Co 35710, Co 35731, Co 35752, Co 35765, and Co 35766. Colonies from Yonaguni Is are ZMTAU Co 35131: 9-12 pinnules, Co 35132: 12-14 and Co 35134: 11-13. Colonies from Madagascar: ZMTAU Co 36013: 10-13 pinnules and Co 36129: 12-13.

The sclerites of the colonies noted above featured the full array of morphologies, mostly corresponding to that of the syntypes (Figures 2-3). To demonstrate the vast variation in shape and size of the sclerites, SEM images of sclerites of several sequenced colonies are presented for the Taiwan material: ZMTAU Co 35692 (Figure 7), Co 35737 (Figure 8), Co 35765 (Figure 9), Co 35709 (Figure 10), Co 35707 (Figure 11), Co 35710 (Figure 12), and Co 35712 (Figure 13), Yonaguni: ZMTAU Co 35131 (Figure 14) and Madagascar Co 36129 (Figure 15), and Co 36013 (Figure 16). Figures 7-16 demonstrate the morphological variability of the sclerites, with all being conglomerates comprised mainly of spheres and spherules and occasionally dumbbells. The SEM images revealed that their outer surface is sometimes bristly (Figures 7 B–D, 8B, 13 A–B, 14, 15A, 17) but commonly rather smooth (Figures 8A, 10 A–B, 11 A–B, 15B, 16). It is interesting to note that the spheres are sometimes embedded in a calcareous lamella-like structure (Figure 7A). Dumbbells were revealed in some colonies (Figures 8B, 12B, 14, 15C, 17) as well as twisted dumbbells (Figures 9, 11C, 12B). Similarly, as noted above for the syntypes, the above SEM images indicate that the aggregates tend to disintegrate during sclerite preparation and therefore their actual dimensions cannot be determined.

The molecular results indicate that despite the differences in pinnule count and sclerite morphology, all the colonies should be assigned to the same species (Figure 6). Consequently, the pinnule count is of no diagnostic value for species delineation within Conglomeratusclera . C. coerulea thus accommodates colonies with one row of pinnules on the margins of the polyp tentacles, but featuring a remarkable range of pinnule numbers (see above). In addition, the variable sclerite morphologies found in the different colonies (Figures 7-16) both encompass and exceed the range observed among the syntypes of C. coerulea (Figures 2 A–B). The current results provide further support for the recent findings of McFadden et al. (2017) who argue that the pinnule count used in the taxonomy of Xeniidae , explicitly in the genus Ovabunda (see references in Halàsz et al. 2014), is not indicative of species boundaries. It should be noted that in contrast to the relatively uniform morphology of Ovabunda sclerites recorded across the four genetic clades presented by McFadden et al. (2017), colonies of C. coerulea exhibit an unprecedented and bewildering array of sclerite morphologies (Figures 2A, B, 7-16).

Material that was examined, but not sequenced, comprised both freshly collected colonies and museum specimens. Their colony and polyp morphologies, including the pinnule counts, are in agreement with the findings presented above. Noteworthy are some colonies for which SEM or light microscopy could not detect any sclerites. There are several suggested reasons for this: (1) actual lack of sclerites; (2) their low incidence which led to a failure to detect them by SEM; or (3) preservation procedures, such as acidic conditions that may have caused sclerite dissolution.

The museum material examined included colonies from the BMNH, all collected from the western Indian Ocean (see above). Some of the colonies were originally identified by L.M.I. Macfadyen as Cespitularia coerulea (BMNH 1912.2.24.66 and 1933.3.13.175; Figure 17), C. mollis (BMNH 1933.313.177), C. taeniata (BMNH 1912.2.24.65, 1933.5.3.301 and 1933.3.13.176) and Cespitularia wisharti Hickson, 1931 (BMNH 1934.3.28.10). These BMNH colonies feature one row of 8-13 pinnules along each side of their tentacles and the morphology of their sclerites corresponds to that of Conglomeratuscslera coerulea [e.g., BMNH 1912.2.24.65 (Figure 18), 1912.2.24.66 (Figure 19), 1912.2.24.67 (Figure 20)]. The morphological examination therefore indicates that the BMNH material should be assigned to the above species. The sclerites of the colony from the Great Barrier Reef, Australia, USNM 60795 (Figure 21), as well as those of USNM 54000 and 54003 (sclerites not shown), collected in Madagascar, similarly confirmed them to be C. coerulea . The RMNH material too revealed colonies that have now been assigned by us to C. coerulea , featuring one row of 8-16 pinnules along each side of their tentacles as well as sclerites: RMNH Coel 42160 (Figure 22), Coel 42161 (Figures 23-24) and RMNH Coel 42162 (Figure 25). These images reveal spheres, either in a conglomerated form or individuals (Figures 22-25), and in other colonies mostly twisted dumbbells, either aggregated or individual (Figure 22). Interestingly, some crystalline bundles were noted among the spheres (Figure 24).

Distribution.

Kenya; Zanzibar; Tanzania; Glorioso Islands; Mauritius; Seychelles; Mayotte; Taiwan; Philippines; Japan (Tanabe, Wakayama, Shikoku); Ryukyu Archipelago; Indonesia.