Polynoidae, Kinberg, 1856

Britayev, Temir A., Gil, João, Altuna, Álvaro, Calvo, Marta & Martín, Daniel, 2014, New symbiotic associations involving polynoids (Polychaeta, Polynoidae) from Atlantic waters, with redescriptions of Parahololepidella greeffi (Augener, 1918) and Gorgoniapolynoe caeciliae (Fauvel, 1913), Memoirs of Museum Victoria 71, pp. 27-43 : 36-41

Polynoidae Parahololepidella greeffi ( Augener, 1918)

Polynoidae Tottonpolynoe symantipatharia Pettibone, 1991b Distichopathes filix ( Pourtalès, 1867) 1,2

Elatopathes abietina ( Pourtalès, 1874) 1,2

cf. Antipathes cylindrica Brook, 1889 1,2

cf. Antipathes cylindrica Brook, 1889 1,2

Tanacetipathes tanacetum ( Pourtalès, 1880) 3,4

Stylopathes columnaris ( Duchassaing, 1870) 3,4

Stylopathes tenuispina Silberfeld, 1909 5

Stylopathes columnaris ( Duchassaing, 1870) 4,5

Leiopathes sp. 6

Bathypathes cf. alternata Brook, 1889 7

Elatopathes abietina ( Pourtalès, 1874) 1,2

Distichopathes filix ( Pourtalès, 1867) 1,2

Tanacetipathes cf. spinescens ( Gray, 1857) 8

Parantipathes sp. 3

Syllidae Bollandiella antipathicola ( Glasby, 1994) Antipathes sp. 2,9,10

expedition, 1423 m depth, 42º28.838'N 011º55.873'W.

Avilés Canyon System , Bay of Biscay, N Iberian Peninsula. Host Corallium niobe . MNCN 16.01 /14341: 1 specimen, Sta. DR 16- 05/08/2010: 1 specimen from one colony fragment and several colony fragments without polychaetes but showing modifications of the axis front resulting from the interaction with the polychaetes, INDEMARES 2010 expedition, 928 m depth, 44º01.509'N 005º42.898'W .

Additional material: Voucher specimens deposited in the IEO laboratory, Gijón ( Spain), and INSUB, Museo de Okendo , Donostia-San Sebastián. Galicia Bank, NW Iberian Peninsula. Host Candidella imbricata . Sta. DR 10-14/08/2010: 32 specimens from seven colonies and fragments, INDEMARES 2010 expedition, 1482 m depth, 42º27.672'N 011º59.233'W . Sta. DR 16-24/08/2010: 18 specimens from one colony and fragments, INDEMARES 2010 expedition, 1423 m depth, 42º28.838'N 011º55.873'W . Sta. DR 04-22/07/2011: 1 specimen from one colony fragment, INDEMARES 2011 expedition, 1288 m depth, 42º58.419'N 12º02.982' W . Sta. DR 12-05/08/2011:ca. 72 specimens from three colony fragments, INDEMARES 2011 expedition, 1585 m depth, 42º32.157' N 12º03.795'W . Host Corallium sp. Sta. DR 08-13/08/2010:one dead colony with likely worm-induced galleries, without worms, INDEMARES 2010 expedition, 1196 m depth, 42º55.941'N 12º05.149' W.

Diagnosis. Prostomial lobes rounded, without cephalic peaks; first pair of elytrae modified with crescent shaped area on lateral side, transparent,chitinous,withscatteredroundedmicrotubercles and elongate globular micropapillae (figs. 5C, 5D, 8A, 8B); remaining elytrae translucent almost circular with slightly folded borders (fig. 8C); dorsal cirri with scarce clavate papillae, mainly at basis (fig. 8D); parapodia as in generic diagnosis (figs. 5H, 8D), with big, digitate nephridial papillae (fig. 8E); 0–3 notochaetae, stout, with blunt tips (figs. 5E, 8F); 8–15 neurochaetae, as stout as notochaetae, bidentate (figs. 5F, 5G, 8G, 8H).

Measurements. 37-49 chaetigers, L 7.0-17.0 mm, WW 0.9-1.6 mm, WC 1.4-2.3 mm.

Remarks. The Iberian specimens agree well with the re-description of the species by Pettibone (1991a), except in the presence of clavate papillae on dorsal cirri, which were neither mentioned nor figured in the original description.

Ecology. Gorgoniapolynoe caeciliae lives in association with different species of octocorals belonging to the Acanthogorgiidae , Primnoidae and Coralliidae ( Barnich et al., 2013; Bayer, 1964; Eckelbarger et al., 2005; Pettibone, 1991a). The polychaetes were observed in all sampling stations where the host C. imbricata ( Primnoidae ) was obtained, from 1288 m to 1585 m deep, living inside galleries formed by highly modified sclerites of the gorgonian (figs. 9A-9D), similar to those described by previous authors in the same host (see Cairns, 2004, on colonies from W Atlantic),butalsoontheacanthogorgiidgorgonian Acanthogorgia armata Verrill, 1878 and A. aspera Pourtalès, 1867 , and on the primnoid gorgonian Callogorgia sp. (see Barnich et al., 2013; Britayev, 1981, and references herein).

Similar galleries (some with worms inside) were observed in other species of Candidella , such as C. helmintophora ( Nutting, 1908) from Hawaii ( Cairns, 2009; Nutting, 1908). Other Hawaiian gorgonians, belonging to the genus Narella ( Primnoidae ), such as N. alata Cairns & Bayer, 2008 , N. macrocalyx Cairns & Bayer, 2008 and N. vermifera Cairns & Bayer, 2008 ( Cairns & Bayer, 2008), showed similar galleries with worms. However, the polychaetes in these four host species were not identified. Thus, it is not possible to assess whether they belong to the same polynoid species or to a similar one. For instance, Gorgoniapolynoe galapagensis Pettibone, 1991a was described in association to Narella ambigua ( Studer, 1894) from Galapagos Islands (Eastern Central Pacific Ocean) and Gorgoniapolynoe bayeri Pettibone, 1991a , associated with Narella clavata ( Versluys, 1906) , occurred in Philippine Islands (North Pacific Ocean).

Gorgoniapolynoe caeciliae was also reported in association with five species of Corallium ( Coralliidae ), C. bayeri Simpson & Watling, 2011 , C. johnsoni Gray, 1860 , C. niobe Bayer, 1964 , C. secundum Dana, 1846 and C. tricolor ( Johnson, 1898) ( Bayer, 1964; Fauvel, 1913; Hartmann-Schröder, 1985; Simpson & Watling, 2011; Stock, 1986). It must be pointed out that Stock (1986) reported C. profundum Dana, 1846 as a host for the polychaete, but this species does not exist and most likely was a misspelling for C. secundum . When associated with Corallium , including our sample of C. niobe (figs. 9E, 9F), the worms induce malformations in the host branches, which form entirely covered galleries that contain a single worm inside (see Barnich et al., 2013, and references herein). Similar galleries were also depicted by Bayer (1956) on C. secundum and Bayer (1964) on C. niobe , but the worms were not identified. The dead colony of Corallium found in Galicia Bank completely lacked the original soft tissues (those observed in the picture correspond to secondary colonization of the coral skeleton by a zoantharian), this preventing the identification to species level. However, the skeleton also showed traces of several galleries (fig. 10), which agree with those found on the living colonies of C. niobe harbouring the polychaete at the Avilés Canyon System.

In all cases, all the galleries were not excavated on the coral skeleton but appeared to be produced by the coral tissues and skeleton overgrowing the original soft tube produced by the worm (which may still be observed laying between the coral tissues and the worms themselves), in a similar way to the modifications induced by Eunice norvegica ( Linnaeus, 1767) on its host scleractinian coral Lophelia pertusa ( Linnaeus, 1758) ( Mueller et al., 2013) . This suggests that G. caeciliae may play an equivalent, functional role to that of E. norvegica in structuring the assemblages of its coral hosts.

Distribution. Widely distributed in the NW and NE Atlantic, from 400-1500 m depth according to Barnich et al. (2013). The present report includes a slightly deeper depth range (down to 1585 m) and is the first mention of the association between G. caeciliae and C. imbricata for Spanish waters. The presence of the polychaete in different locations from N and NW Iberian waters was previously reported by Fauvel (1913), Hartmann-Schröder (1985) and Pettibone (1991a) in association with Corallium species (i.e. C. niobe and C. johnsoni ).