Palythoa mutuki (Haddon & Shackleton 1891)

Originally described from the Torres Strait, Australia, this species was redescribed in detail in Ryland and Lancaster (2003). Although all specimens in this grouping match with previously reported Palythoa mutuki based on sizes (average polyp height 9.6 mm, range 3–31 mm, average width 4.8 mm, range 2–8 mm, n=12 specimens) and overall morphology (‘intermediae’ or ‘liberae’ [Pax 1910]; visible capitulary ridges on closed polyps [Ryland and Lancaster 2003]) (Figure 6B), we have identified all specimens in this study as “cf.”. Recent work has shown the presence of more than two closely related species groups within Palythoa mutuki (Reimer et al. 2006b, 2013a) that are exceedingly difficult to distinguish without molecular data. For this reason, we have preliminarily assigned “cf.” to these specimens.

Regions recorded in this study (Figure 7). West Bali (4), eastern Bali (5), Komodo Island (8), Spermonde Archipelago (9), Taka Bone Rate (11), Maisel Islands (13), Moluccas (14), Cebu (21). Previous records. Ryland and Lancaster (2003) in their treatment of Palythoa mutuki also mentioned records from Fiji, and synonymized records of other species from Tuvalu (Gemmaria willeyi Hill & Whitelegge, 1898), eastern Australia (Gemmaria arenacea Wilsmore, 1909; Palythoa yongei Carlgren, 1937; Palythoa australiensis Carlgren, 1950) and Singapore (Palythoa singaporensis Pax & Müller, 1956) with this species. However, asides from the specimens directly examined by Ryland and Lancaster, there is much confusion over the true identity of these species. For example, Ryland and Lancaster (2003) themselves state that Gemmaria willeyi is likely a Zoanthus species based on the figures in the original description. Ryland and Lancaster state “Probably only the use of genetic methods, so successfully applied by Burnett et al. (1997), will settle identities over wide geographic areas”. However, in the Pacific, records of this species with phylogenetic confirmation have previously been reported from the Great Barrier Reef in Australia (Burnett et al. 1997), Singapore (Reimer and Todd 2009), to the south Pacific coast of Japan (e.g. Reimer et al. 2006b, 2007b), New Caledonia (Sinniger 2006), and across to the Galapagos (Reimer and Hickman 2009), and thus it is known that this species has a very wide Indo-Pacific distribution.