Zoanthus sansibaricus Carlgren, 1900

Reimer, James D., Poliseno, Angelo & Hoeksema, Bert W., 2014, Shallow-water zoantharians (Cnidaria, Hexacorallia) from the Central Indo-Pacific, ZooKeys 444, pp. 1-57 : 6

Taxon classification Animalia Zoantharia Zoanthidae

2. Zoanthus sansibaricus Carlgren, 1900 Figures 2B, 3

Specimens examined

(n=1). RMNH Coel 40476, Rumphius Biohistorical Expedition station 27, Leitimur, south coast, Hutumuri, Ambon, Moluccas, depth = intertidal, collected November 26, 1990 by M.S.S. Lavaleye.

Photographic records

(n=9). Southeast Siberut, West Sumatra (01°44'S, 99°15'E), December 15, 1996; east Menjangan Island, West Bali (08°05'25"S, 114°31'40"E), May 21, 1998; west Pulau Lumu Lumu, Spermonde Archipelago, South Sulawesi (04°58'30"S, 119°12'30"E), October 8, 1997; west Pulau Kudingareng Keke, Spermonde Archipelago, South Sulawesi (05°06'20"S, 119°17'03"E), May 29, 1997; northwest Pulau Barang Lompo, Spermonde Archipelago, South Sulawesi (05°02'35"S, 119°19'10"E), July 21, 1998; south Pulau Samalona, Spermonde Archipelago, South Sulawesi (05°07'45"S, 119°20'25"E), October 27, 1997; west Pulau Lae Lae Besar, Spermonde Archipelago, South Sulawesi (05°08'15"S, 119°23'10"E), November 12, 1997; northwest Pulau Lae Lae Keke, Spermonde Archipelago, South Sulawesi (05°07'10"S, 119°23'25"E), October 11, 1997; Station BER.26, northeast Buliulin (south of Samama Island), Berau Islands, East Kalimantan, (02°07'07"N, 118°20'32"E), October 15, 2003.

Description.

Can form colonies of up to 1 m2, but often forming much smaller colonies in cracks and small overhangs in intertidal and shallow waters (<5 m). with polyps well clear and free of the coenenchyme ( “liberae”) ( Pax 1910, Reimer et al. 2006b). Adult polyps 2-12 mm in diameter when open, up to 20 mm in length but usually shorter, particularly in locations with strong currents or waves. The sole specimen (RMNH Coel 40476) in this study has small polyps (height average 2.8 mm, range 2-5 mm; width average 2.4 mm, range 1.5-4 mm) within the reported range of this species. External polyp surface generally uniform, light to dark gray-blue with no significant markings or patterns. Tentacles 40-58, mesenteries 48-54. Wide variation in oral disk colors, patterns, and in colors of tentacles (Figure 2B) ( Reimer et al. 2004, 2006a) (partially adapted from Reimer and Hickman 2009).

Distribution.

Regions recorded in this study (Figure 3). West Sumatra (1), West Bali (4), Spermonde Archipelago (9), Moluccas (14), Berau Islands (19).

Previous records. This species has previously been reported from Zanzibar (type locality), Singapore ( Reimer and Todd 2009), Taiwan ( Reimer et al. 2011c, 2013a), Palau ( Reimer et al. 2014a), southern Japan ( Reimer et al. 2004, 2006a, Kamezaki et al. 2013), and is considered to have a very wide Indo-Pacific distribution.

Remarks.

Based on its wide Indo-Pacific distribution, it is very likely that this zooxanthellate species is much more common within the CIP than reported here. One possible reason for the lack of records from the CIP is that this species is most commonly found in the intertidal zone, which is under-sampled during SCUBA surveys. However, this species is also found to depths of 52 m ( Kamezaki et al. 2013), although below the shallow littoral zone it rarely forms colonies>100 polyps.

Additionally, as preserved specimens of Zoanthus are notoriously hard to identify to species level, the large number of unidentified Zoanthus specimens in this study undoubtedly include some Zoanthus sansibaricus colonies. This is also likely one important reason explaining the presence of comparatively more photographic records of this species in this study, as in situ identification of colonies with expanded oral polyps is easier than preserved specimen identification.

This species may be the same as Zoanthus coppingeri Haddon & Shackleton, 1891b from the Great Barrier Reef, Australia, based on molecular data (Reimer, data not shown), which has been reported to be a senior synonym of Zoanthus jukesii Haddon & Shackleton, 1891b, Zoanthus macgillivrayi Haddon & Shackleton, 1891b, Zoanthus annae Carlgren, 1937, Zoanthus mantoni Carlgren, 1937, Zoanthus fraseri Carlgren, 1937, all described from the Great Barrier Reef based on nematocyst data ( Burnett et al. 1997).