(Fig. 30 C, D)
Pomatoceros tetraceros Schmarda, 1861: 30, plate 21 fig. 179 [NSW, Australia].
Pomatoceros tetraceros.— Beesley et al. 2000: 8, Fig. 1.6B [reproduction of Schmarda’s original figure].
Pomatoceros elaphus Haswell, 1885: 663 –665, pl. 31 fig. 7, pl. 32 figs 9–10 [Port Jackson, NSW].
Spirobranchus semperi.— Augener 1913: 82 [Sharks Bay, WA; extensive description]; 1914: 148 – 142 [same]; Straughan 1967 b: 246 –247 [Qld, Australia; diagnosis].
Spirobranchus tetraceros. — Johansson 1918: 7 –10, fig. 2 [Cape Jaubert, WA]; ten Hove 1970: 3 –13, 47– 49, figs 1–25 [synonymy, in part; see Remarks]; Imajima & ten Hove 1984: 51–52 [Truk Islands, Ponape and Majuro Atoll; Lizard Island, Qld and Capes Farquhar and Jaubert, WA]; Pillai 2009: 158 –162, fig. 44 A–C, 45 A–I, 46 A–K [Kimberley, WA, Australia].
Spirobranchus giganteus not (Pallas, 1766).— Dew 1959: 45, fig. 17 [at least in part, see Remarks].
Spirobranchus tricornis.— Straughan 1967 a: 39 [Qld; diagnosis]; 1967 b: 244, fig. 14 b–d [NSW, Qld, Australia; diagnosis].
Spirobranchus coutierei.— Straughan 1967 c: 224, fig. 1 a–d [NT, Australia; diagnosis].
Material examined. AM W. 28328 (6), stn. 16, North Point, 14 ° 40 'S, 145 ° 28 'E, sloping reef with mainly dead & thinly silted corals, 17 m, coll. H. ten Hove, P. Hutchings & M. Reid, 1 Mar 1986; AM W. 41819 (2), Yonge Reef, back reef patch, 14 ° 36 'S, 145 ° 37 'E, coll. R. Smith, 11 Nov 1985; AM W. 41830 (4), Yonge Reef, back reef bommie, 14 ° 36 'S, 145 ° 37 'E, in Stylophora pistillata, coll. R. Smith, 7 Nov 1985; AM W. 42352, Yonge Reef, back reef, 14 ° 36 'S, 145 ° 37 'E, coll. R. Smith, 7 Nov 1985; AM W. 45073, MI QLD 2417; AM W. 47304, North Direction Island, Fore Reef, 14 ° 44 ' 48 "S, 145 ° 30 ' 18 "E, coral rubble, 12 m, coll. M. Blazewicz-Paskowycz, 24 Feb 2009; AM W. 47349, inter-reef sand, 14 ° 23 ' 24 "S, 145 ° 16 ' 24 "E, artificial substrate, 10 m, coll. M. Timmers, 9 Feb 2009; MAGNT W025492, North Point, Fore Reef, 14 ° 38 ' 42 "S, 145 ° 27 ' 12 "E, coral rubble, 2 m, coll. C. Watson, 12 Apr 2008; SAM E 3609, Ser 91, stn.G 231, Coconut Beach, 14 ° 41 'S, 145 ° 28 'E, scuba, coll. G. Rouse & E. Kupriyanova, 26 Oct 2005; ZMA V.Pol. 4883 (as Sp. oligotrema, juvenile), North Reef, 14 ° 40 'S, 145 ° 27 'E, underside of boulders on rock, low tide, little sand, coll. H. ten Hove, 22 Jun 1983; ZMA V.Pol. 4897 (10), stn. 18, lagoon near east entrance, sheltered side of reef, near sandy bottom, 2–20 m, coll. H. ten Hove, 3 Mar 1986; ZMA V.Pol. 4911 (9), Turtle Beach, from underside of dead & living corals, generally fairly cryptic, about 6 m, coll. H. ten Hove, 22 Jun 1983; ZMA V.P o l. 5317, stn.G 247, channel near Bird Islet, 10 m, coll. G. Rouse & E. Kupriyanova, 3 Nov 2005; ZMA V. Pol 5322, stn.G 237, Patch Reef near Palfrey Island, 6 m, coll. G. Rouse & E. Kupriyanova, 30 Oct 2005.
Diagnosis. Opercular plate mostly flat, sometimes conical; basally carrying 1 medio-ventral spine and 2 laterodorsal spines (“ tricornis ”); alternatively the medio-ventral spine appears as two fully separate spines which with the two latero-dorsal spines leads to 4 primary spines (“ tetraceros ”). All spines are at least split once, generally twice or three times resulting in 6–14 spine tips. Completely conical opercula just with 3 rudimentary spines or without. Peduncular wings with finger-like processes distally (rarely without).
Remarks. We have refrained from giving an exhaustive list of synonyms and given some “trusted” Australian records only. This taxon is regarded to be a complex of species in recent years (e.g., Smith 1985: 51–61; Fiege & ten Hove 1999: 362; ten Hove & Kupriyanova 2009: 12, 98; Ben-Eliahu & ten Hove 2011: 91). Its synonymy is very complicated and far from settled. WoRMS (http://www.marinespecies.org/polychaeta/aphia.php?p=taxdetails &id= 131055)—based mainly on ten Hove (1970) as last revision and not fully taking into account Pillai (2009) — lists for this species 33 combinations (including spelling errors) of names, under essentially 8 generic and 17 specific names, as well as 4 more likely synonyms in the remarks. This does not even take into account the frequent misidentifications of Indo-West Pacific material ranging from Pomatoceros triqueter (Linnaeus, 1758) to Spirobranchus giganteus (Pallas, 1776). Ben-Eliahu & ten Hove (2011: 91) give an extensive discussion. The (certainly partly anthropogenic) distribution is very unlikely for a single species in our present view: circumtropical, Lessepsian migrant to the Levantine Mediterranean and in Australia down to subtropical/temperate New South Wales, moreover from intertidal rocks to endobiotic in corals.
Indicative of the problems in this taxon is Dew’s (1959: 45–46) record. Following e.g., Fauvel (1933 a: 78–79, Gulf of Suez, Gulf of Aqaba) and Monro (1937: 317, Arabian Sea) she identified her material as Sp. giganteus. However, her figure 17 clearly belonged to Sp. tetraceros as well as her essentially NSW samples, while (part of) her material from Queensland belonged to what we presently would attribute to Sp. corniculatus (material largely restudied by HtH in 1970, 1986). Straughan (1967 a, b, c) attributed three different names to her material, but checking that ten Hove (1970: 47–49) could not find consistent agreement between morphology and attributed names.
Distribution. Indo-West Pacific, including Australia (NSW, Qld, WA).