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Terebellides lanai is recorded from shallow subtropical waters off Brazil, and two new species of Terebellides are described from cold-temperate waters off Argentina: T. totae from Blanca Bay and T. malvinensis from the continental shelf off Argentina.

Terebellides sirius sp.n. Figs 15, 16, 17 Holotype: ANDEEP II, St. 132 - 6, GKG (ZMH- 26005) Paratypes: ANDEEP II, St. 132 - 6, GKG [drawing, MG photo] (ZMH- 26004); ANDEEP II, St. 132 - 6, GKG (ZMH- 26006); ANDEEP II, St. 131 - 8, GKG (AM W 39663); ANDEEP II, St. 131 - 8, GKG [MG photo, SEM, stub MI 541 & MI 542] (AM W 38716); ANDEEP II, St. 132 - 4, GKG (2 specimens, AM W 39664, AM W 39665); DZMB-HH 6309 - 1, ANDEEP III, St. 121 - 12, GKG (ZMH- 26007) Description: (Based on both holotype and paratypes) Holotype 6 mm in length, 1 mm width, complete with 35 abdominal chaetigers. Paratypes range from 6 mm to 1.2 cm in length to 1 to 1.2 mm in width with 30 to 35 abdominal chaetigers. Head region: Tentacular membrane greatly expanded. Lower lip rectangular, distinctly folded upwards, also expanded (Fig. 15). Tentacles short simple ones plus long tentacles with expanded tips present on outer margins of tentacular membrane (Fig. 16 A, D). Branchiae: Branchial lobes fused about 20–40 % with each other, lamellae broad, loose, rather few present, filamentous tips absent (Fig. 16 A, B). Posterior branchial lobes shorter (about 70–80 %) than anterior ones. Fifth branchial lobe absent. Annulation of branchial stem present. Only one specimen with fully developed branchiae, remaining specimens with anterior branchial lobes somewhat drop-like in shape, arranged at an angle of about 120 ° to each other (Fig. 17). Ciliary fields between branchial lamellae not apparent (Fig. 16 B, C). Anterior chaetigers: Notopodia from segments 3–20, 18 pairs. First notopodia reduced in size with chaetae more or less originating from body wall (Fig. 16 D) and second notopodia smaller than subsequent ones (Fig. 16 D). Notochaetae, capillaries with fine tips and arranged in two tiers (Fig. 16 E). Neuropodia present from segment 8 (chaetiger 6), those of first neuropodia geniculate hooks, about 5–7 per side, sharply bent with extended fine tips and inflated bases (Fig. 16 F). Subsequent neuropodia with long shafted denticulate hooks with main fang and several multidentate rows of teeth above, not vertically aligned, so providing a dental formulae not possible (Fig. 16 G), neuropodia become increasingly erect pinnules posteriorly. Abdominal uncini few within a torus and with elongate hooks, main fang completely covered by numerous elongate accessory teeth (Fig. 16 H). Lateral lappets: Present from TC- 1–6, with TC- 1> 2 = 3> 4 = 5 Ventral pads: Ventrum of thoracic segments slightly glandular with anterior margins of segments elevated, especially marked on chaetigers 1–4. Nephridial papillae: Present on segments 3, 6, 7, possibly also 5, globular. MG staining pattern 1 (Figs 2, 17): Solid on anterior and striped in median thorax. No apparent white bands or pronounced anterior margins present. Both noto- and neuropodia stain. Pygidium: With two low lateral papillae. Remarks: Terebellides sirius sp.n., is characterised by four branchial lobes being partially fused along their length, lobes made up of a few loosely packed lamellae with no terminal filamentous tips, lateral lappets on chaetigers 1–6 with the first three the largest and similar in size and with a greatly expanded lower lip. This new species T. sirius sp.n., belongs to a group of species with branchial lobes at least partially fused along their length (Terebellides kowinka Hutchings & Peart, 2000, Terebellides californica Williams, 1984, Terebellides horikoshii Imajima & Williams, 1985, Terebellides japonica Moore, 1903). Terebellides sirius sp.n., can be separated from T. kowinka by the branchiae lacking filamentous tips, and the other species in this group have branchiae with lamellae densely packed (T. toliman sp.n., this paper and T. canopus sp.n., this paper) whereas T. sirius sp.n., like T. kowinka has branchiae with only a few lamellae. For more details see the key. Habitat: Western Weddell Sea in 2085–3068 m. Known only from type locality. Etymology: The specific name sirius is one of the brightest stars in the constellation Carina.

Terebellides mediterranea spec. nov. (Figures 5���8, 12 a, d, e, 13; Table 1) Material examined. A total of 10 specimens were examined (11.9% of the total Terebellides specimens collected). Type material: Station SJ 0 0 5 - 30.08. 2004 (PMR- 14558, 2 paratypes). Station SJ 0 0 7 - 27.02. 2003 (PMR- 14559, 1 holotype; PMR- 14560, 1 paratype on SEM stub); 28.05. 2003 (PMR- 14561, 1 paratype; PMR- 14562, 1 paratype on SEM stub); 29.01. 2004 (MNCN 16.01/ 14716, 1 paratype). Non-type material: Station SJ 0 0 5 - 27.02. 2003 (1 spec.) (coll. BM). SJ 0 0 5 - 30.08. 2004 (2 specs.) (coll. BM). Comparative material: Terebellides californica Williams, 1984. Paratype AM W 197111. Type specimens of T. californica were requested to the Los Angeles California Natural History Museum, but unfortunately they were not available for study. However, general characteristics of this species presented in Hutchings and Peart (2000) and Sch��ller and Hutchings (2010) were corroborated by P. Hutchings who kindly checked the paratype of this species deposited in the Australian Museum (Sydney) (AM). Description based on holotype. Complete specimen, 23 mm long and 2.0 mm wide; body tapering posteriorly with segments increasingly shorter and crowded towards pygidium. Prostomium compact; large tentacular membrane surrounding the mouth provided with many long buccal tentacles with expanded tips (Fig. 5 a, 8 a). SGI forming an expanded structure below tentacular membrane. Lateral lappets on SGIII���VII, CH 1���5, being larger and continuing ventrally in SGIII���V declining in size posteriorly (Fig. 5 a). No conspicuous dorsal rounded projection on anterior chaetigers or oval-shaped glandular region in CH 3. Branchiae arising as single structure from SGIII, consisting of a single stalked structure situated mid-dorsally (Fig. 5 a) made up of two pairs of lobes fused along most of their lengths; lower pair much shorter then upper pair. Pointed projection of posterior region of both upper and lower lobes and large anterior branchial projection (fifth lobe) present (Fig. 5 b). Both sides of branchial lamellae provided with several parallel bent rows of cilia (Fig. 6 a) and tufts of cilia on the outer edge (Fig. 6 b). Eighteen pairs of thoracic notopodia (SGIII ���XX). Notopodia present from CH 1, larger than subsequent notopodia (Fig. 5 a, c, d); notochaetae of CH 1 much longer than following notochaetae. All notochaetae simple capillaries with textured surface (Fig. 6 c). Neuropodia present as sessile pinnules from CH 6 (SGVIII) to pygidium and provided with uncini in single rows starting from CH 7 (SGIX) throughout. First thoracic neuropodia (CH 6) provided with 4���5 sharply bent, acute tipped, geniculate acicular hooks (Fig. 6 d). Minute teeth forming a capitium on geniculate chaetae not observed. Second and all subsequent thoracic neuropodia with up to 10���16 uncini per torus (Fig. 7 a). Uncini provided with long shafted denticulate hooks with 3���4 teeth above main fang surmounted by 6���7 shorter teeth and an upper crest of several smaller denticles (Fig. 7 b), dental formula MF: 3���4: 6���7:���. Thirty-two abdominal neuropodia as erect pinnules provided with about 33 uncini per torus (Fig. 7 c); uncini with four teeth above main fang surmounted by a fifth tooth in the middle, an upper crest of 4 teeth (Fig. 7 d) and a variable number of smaller teeth, dental formula MF: 4: 1: 4:���. One large papilla located behind first thoracic notopodia (Figs 5 d; 8 b), and two button-hole like pairs of nephridial openings; located dorsal to each notopodium of SGVI and VII (CH 4 and 5) (Fig. 8 c, d). Pygidium blunt, funnel-like depression. MG staining pattern 1 (Figs 12 a,d,e; 13 a): compact green colouration in CH 1 ��� 3, then turning into striped pattern in CH 4 ��� 12 and fading in the following segments. Colour in alcohol pale brown (Fig. 13 b). Remarks. The presence of large notopodia provided with long notochaetae in the first thoracic chaetiger is a character usually employed to discriminate species in taxonomic keys of the genus Terebellides (Garraffoni & Lana 2003; Solis-Weiss et al. 2009) and also in phylogenetic studies (Garraffoni & Lana 2004). Following Hutchings and Peart (2000) two species have this diagnostic character: T. kobei Hessle, 1917 and T. californica Williams, 1984. Terebellides kobei was described by Hessle (1917) from specimens collected in Kobe Bay (Japan), later reported from the same area by Imajima and Hartman (1964) and described in more detail by Imajima and Williams (1985). Surprisingly, this work ignores the record of Williams (1984) in the Indian Ocean (Mozambique Channel) probably due to simultaneous date of publication. Our specimens clearly differ from T. kobei in having notopodia and notochaetae of CH 1 much longer (similar to Williams��� material), by the absence of a conspicuous triangular lobe and a glandular area at the level of notopodia of CH 3 (Table 1) and by the similar length and high degree of fusion of posterior branchial lobes (see also Hutchings & Peart 2000, Table 3 A). Terebellides californica was described by Williams (1984) from the Pacific Ocean (Oregon to Western Mexico) at shelf and slope depths, and later reported from the same area by Hern��ndez-Alc��ntara and Sol��s-Weiss (1999) and Hilbig (2000). Hern��ndez-Alc��ntara and Sol��s-Weiss (1998) report T. californica for the Mexican Caribbean but we suspect that this may correspond to other species with large CH 1 as well. Williams (1984) characterized the taxon only by the ���very well developed first chaetiger with greatly prolonged fine notosetae��� (Williams 1984, p. 128). The species was later redescribed by Hilbig (2000) proposing a ���trilobed structure of the peristomium��� as potential new diagnostic character. This character was not observed in our specimens, but in our opinion its relevance should be taken with caution as its presence in the species has not been sufficiently assessed. Terebellides mediterranea spec. nov., differs from T. californica in branchial structure in addition to their very different geographical location���shelf and slope depths of the Pacific Ocean in T. californica vs. shallow waters in the Adriatic Sea in T. mediterranea spec. nov. In this sense, in T. mediterranea spec. nov., a large fifth branchial lobe is present and posterior pairs of lobes (first to fourth lobes) are fused along most of their lengths while T. californica lacks a fifth branchial lobe and posterior pairs of lobes are moderately fused (Hutchings & Peart 2000; Sch��ller & Hutchings 2010). Habitat. Offshore stations in the northern Adriatic Sea on silty sand bottom on 31 m depth. Known only from type locality. Distribution. Adriatic Sea. Etymology. The name of the species refers to the Mediterranean Sea., Published as part of Parapar, Julio, Mikac, Barbara & Fiege, Dieter, 2013, Diversity of the genus Terebellides (Polychaeta: Trichobranchidae) in the Adriatic Sea with the description of a new species, pp. 333-350 in Zootaxa 3691 (3) on pages 338-342, DOI: 10.11646/zootaxa.3691.3.3, http://zenodo.org/record/248600

Terebellides stroemii Sars, 1835 (Figures 9���11, 12 c, 13) Terebellides stroemii Sars, 1835: 48 ���50, Pl. 12 (labelled 13), Fig. 31 a���e. Terebellides stroemii ���Garraffoni et al. 2005: 14. Garraffoni & Lana 2003: 356. Garraffoni & Lana 2004: 973, Tables 1���2, Figs 5���6. Jirkov 2001: 529, Figs 1���5. Parapar et al. (2011): 14, Figs 11, 12, 13 d. Terebellides stroemi ���Williams 1984: 119, Figs 1 a���c, 3, 6. Imajima & Williams 1985: 11. Holthe 1986 a: 170. Sol��s-Weiss et al. 1991: 147. Bremec & El��as 1999: 177. non Terebellides stroemii ���Hutchings & Peart 2000: 254, Figs. 13 f, 16, Tab. 3. Material examined. A total of 51 specimens were examined (60.7% of the total Terebellides specimens collected) in all four stations studied. Station SJ 0 0 5: 28.05. 2003 (PMR- 14563, 1 spec.; PMR- 14564, 1 spec.); 0 7.06.0 4 (PMR- 14565, 1 spec.); 0 2.12. 2004 (PMR- 14566, 1 spec.; PMR- 14567, 2 specs.). Station SJ 0 0 7: 27.02. 2003 (4 specs.) (coll. BM); 28.05. 2003 (PMR- 14568, 4 specs.); 12.08. 2003 (MNCN 16.01/ 14717, 2 specs.; MNCN 16.01/ 14718, 1 spec.); 29.01.0 4 (PMR- 14569, 2 specs.); 30.08.0 4 (PMR- 14570, 1 spec.). Station LIM K 2: 0 7.07. 2010 (PMR- 14571, 10 specs.); 0 7.07. 2010 (10 specs.) (coll. BM). Station LIM K 5: 0 7.07. 2010 (PMR- 14572, 9 specs.; PMR- 14573, 2 specs. on one SEM stub). Description of Adriatic Sea specimens. Complete specimens ranging from 25 to 34 mm in length and 3.0 to 2.0 mm in width; specimens from LIM stations much larger than ones from SJ stations; body tapering posteriorly with segments becoming increasingly shorter and compact towards pygidium. Prostomium compact; tentacular membrane surrounding mouth and provided with buccal tentacles with expanded tips. First segment forming an expanded structure below tentacular membrane. Lateral lappets on SGIII���IX (CH 1���7) (Fig. 9 a, b). Some specimens with more or less conspicuous dorsal rounded projection in CH 4 ��� 6. An oval-shaped glandular region could be seen in lateral part of thoracic CH 3 (Fig. 9 a, b). Branchiae arising as single structure from segment 3 consisting of a single stalked structure located middorsally made up of two pairs of posterior lobes fused along most of their length; lower pair of same length but thinner than upper pair (Fig. 9 b). Pointed projection of posterior region of lobes present in both lobes. Anterior branchial projection (fifth lobe) present. Branchiae provided with papillar projections pointing over the edge of the branchial lamellae, the latter also provided with several parallel bent rows of cilia on both sides (Fig. 9 c���d). Eighteen pairs of thoracic notopodia (SGIII ���XX). Notopodia and notochaetae of CH 1 shorter in size to subsequent notopodia. Neuropodia present as sessile pinnules from CH 6 (SGVIII) to pygidium and provided with uncini in single rows throughout. First thoracic neuropodia (CH 6) with 4���5 sharply bent, acute tipped, geniculate acicular hooks (Fig. 10 a). Minute teeth forming a capitium on geniculate chaetae not observed (Fig. 10 b). Second and all subsequent thoracic neuropodia with up to 10���16 uncini per torus. Uncini provided with long shafted denticulate hooks with 2���4 teeth above main fang surmounted by about 3 shorter teeth and an upper crest of several smaller denticles (Fig. 10 c, d), dental formula MF: 2���4: 3:���. Between 30���32 abdominal neuropodia as erect pinnules provided with about 23 uncini per torus; uncini with 4 teeth above main fang surmounted by an upper crest of 3���5 shorter teeth and a variable number of smaller teeth (Fig. 11 a), dental formula MF: 4: 3���5:���. One large, button-hole like nephridial opening on each notopodium of CH 4���5 (Fig. 11 b). Low ciliated papillae located dorsally to all thoracic notopodia from second chaetiger (Fig. 11 c, d). Pygidium blunt, funnel-like depression. MG staining pattern 5 (Fig. 12 c; 13 a): compact green colouration in CH 1���3, after turning into striped pattern in CH 4���12 and fading in following segments. Oval-shaped glandular region of CH 3 also stained but differently to others. Colour in alcohol pale brown (Fig. 13 b), oval region of CH 3 slightly lighter. Remarks. General characteristics of Adriatic specimens agree with those of Icelandic specimens identified as T. stroemii sensu Holthe (1986 a) by Parapar et al. (2011), and therefore differ from those characters referred to this species by Hutchings and Peart (2000) from the study of some Norwegian specimens: presence and degree of development of the anterior lateral lappets, position of nephridial openings and shape of geniculate chaetae. Other characters also in agreement with Parapar et al. (2011) are the MG coloration pattern and the distribution of branchial ciliature. Habitat. The species was reported in a wide range of depths and temperatures in all world oceans, nevertheless, it is impossible to establish with confidence any habitat preferences given that today, it is considered a complex of species. Terebellides stroemii was frequently reported in all parts of the Adriatic Sea on soft bottoms up to a depth of 1,150 m and was considered a species of wide ecological distribution. In this research the species was found in the northern Adriatic Sea on offshore stations on silty sand bottom at 31 m depth and on coastal stations on muddy bottom at 28���29 m depth. Distribution. Boreo-Arctic waters (Hutchings & Peart 2000). Our record in the Adriatic Sea confirms the presence of T. stroemii in Mediterranean waters., Published as part of Parapar, Julio, Mikac, Barbara & Fiege, Dieter, 2013, Diversity of the genus Terebellides (Polychaeta: Trichobranchidae) in the Adriatic Sea with the description of a new species, pp. 333-350 in Zootaxa 3691 (3) on pages 342-344, DOI: 10.11646/zootaxa.3691.3.3, http://zenodo.org/record/248600

Terebellides sirius sp.n. Figs 15, 16, 17 Holotype: ANDEEP II, St. 132 - 6, GKG (ZMH- 26005) Paratypes: ANDEEP II, St. 132 - 6, GKG [drawing, MG photo] (ZMH- 26004); ANDEEP II, St. 132 - 6, GKG (ZMH- 26006); ANDEEP II, St. 131 - 8, GKG (AM W 39663); ANDEEP II, St. 131 - 8, GKG [MG photo, SEM, stub MI 541 & MI 542] (AM W 38716); ANDEEP II, St. 132 - 4, GKG (2 specimens, AM W 39664, AM W 39665); DZMB-HH 6309 - 1, ANDEEP III, St. 121 - 12, GKG (ZMH- 26007) Description: (Based on both holotype and paratypes) Holotype 6 mm in length, 1 mm width, complete with 35 abdominal chaetigers. Paratypes range from 6 mm to 1.2 cm in length to 1 to 1.2 mm in width with 30 to 35 abdominal chaetigers. Head region: Tentacular membrane greatly expanded. Lower lip rectangular, distinctly folded upwards, also expanded (Fig. 15). Tentacles short simple ones plus long tentacles with expanded tips present on outer margins of tentacular membrane (Fig. 16 A, D). Branchiae: Branchial lobes fused about 20���40 % with each other, lamellae broad, loose, rather few present, filamentous tips absent (Fig. 16 A, B). Posterior branchial lobes shorter (about 70���80 %) than anterior ones. Fifth branchial lobe absent. Annulation of branchial stem present. Only one specimen with fully developed branchiae, remaining specimens with anterior branchial lobes somewhat drop-like in shape, arranged at an angle of about 120 �� to each other (Fig. 17). Ciliary fields between branchial lamellae not apparent (Fig. 16 B, C). Anterior chaetigers: Notopodia from segments 3���20, 18 pairs. First notopodia reduced in size with chaetae more or less originating from body wall (Fig. 16 D) and second notopodia smaller than subsequent ones (Fig. 16 D). Notochaetae, capillaries with fine tips and arranged in two tiers (Fig. 16 E). Neuropodia present from segment 8 (chaetiger 6), those of first neuropodia geniculate hooks, about 5���7 per side, sharply bent with extended fine tips and inflated bases (Fig. 16 F). Subsequent neuropodia with long shafted denticulate hooks with main fang and several multidentate rows of teeth above, not vertically aligned, so providing a dental formulae not possible (Fig. 16 G), neuropodia become increasingly erect pinnules posteriorly. Abdominal uncini few within a torus and with elongate hooks, main fang completely covered by numerous elongate accessory teeth (Fig. 16 H). Lateral lappets: Present from TC- 1���6, with TC- 1> 2 = 3> 4 = 5 Remarks: Terebellides sirius sp.n., is characterised by four branchial lobes being partially fused along their length, lobes made up of a few loosely packed lamellae with no terminal filamentous tips, lateral lappets on chaetigers 1���6 with the first three the largest and similar in size and with a greatly expanded lower lip. This new species T. sirius sp.n., belongs to a group of species with branchial lobes at least partially fused along their length (Terebellides kowinka Hutchings & Peart, 2000, Terebellides californica Williams, 1984, Terebellides horikoshii Imajima & Williams, 1985, Terebellides japonica Moore, 1903). Terebellides sirius sp.n., can be separated from T. kowinka by the branchiae lacking filamentous tips, and the other species in this group have branchiae with lamellae densely packed (T. toliman sp.n., this paper and T. canopus sp.n., this paper) whereas T. sirius sp.n., like T. kowinka has branchiae with only a few lamellae. For more details see the key. Habitat: Western Weddell Sea in 2085���3068 m. Known only from type locality. Etymology: The specific name sirius is one of the brightest stars in the constellation Carina., Published as part of Sch��ller, Myriam & Hutchings, Pat, 2013, New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species, pp. 1-45 in Zootaxa 3619 on pages 22-25, DOI: 10.11646/zootaxa.3619.1.1, http://zenodo.org/record/219061, {"references":["Hutchings, P. A. & Peart, R. (2000) A revision of the Australian Trichobranchidae (Polychaeta). Invertebrate Taxonomy, 14 (2), 225 - 272.","Williams, S. J. (1984) The status of Terebellides stroemii (Polychaeta; Trichobranchidae) as a cosmopolitan species, based on a worldwide morphological survey, including description of new species. In: Hutchings, PA (Ed). Proceedings of the First International Polychaete Conference, Sydney, Australia, 1984. The Linnean Society of New South Wales: Sydney, 118 - 142.","Imajima M. & Williams, S. J. (1985) Trichobranchidae (Polychaeta) chiefly from the Sagami and Suruga Bays, collected by the R / V Tansei-Maru (cruises KT- 65 - 76). Bulletin of the National Science Museum, Tokyo, 11 (1), 7 - 18, 5 figures.","Moore, J. P. (1903) Polychaeta from the coastal slope of Japan and from Kamchatka and Bering Sea. Proceedings of the Academy of Natural Sciences, Philadelphia, 55, 401 - 490, plate 23 - 27."]}

Terebellides sp. B Figs 23, 24 Material examined: DZMB-HH 6071, ANDEEP I, St. 46 - 5, GKG (ZMH- 26013) Description: Single specimen 5 mm in length, 5 mm in width, complete with 18 thoracic chaetigers and 22 abdominal uncinigers. Head region: Tentacular membrane compact, but expanded and folded. Lower lip rectangular, distinctly smaller compared to tentacular membrane. Tentacles short simple ones on outer margins of tentacular membrane and longer ones with expanded tips present (Fig. 23). Branchiae: Branchial lobes lost. Annulation of branchial stem not determinable. Anterior chaetigers: First notopodial chaetiger reduced in size with chaetae more or less originating from body wall. Geniculate hooks: Present on TC- 6 (segment 8) only, sharply bent. Lateral lappets: Present from TC- 1–6 or - 7, with TC- 1 = 2 = 3> 4 Ventral pads: Chaetigers 1–5 forming distinct ventral glandular collars with anterior margins elevated, wider than following chaetigers which are not as glandular and with compact anterior margins. Nephridial papillae: Segments 3, 6, 7. MG staining pattern 1 (Figs 2, 24): more or less striped throughout, no staining from TC- 13. Anterior margins of TC- 1 and - 2 darker than subsequent, white bands absent (Fig. 24 B). Noto- and neuropodia stain. Pygidium: 2 low and blunt lateral papillae. Remarks: The species differs from all other species described from the region by having a stout lower lip which is short and rectangular and very inconspicuous compared to other known species of Terebellides. Habitat: Drake Passage, in 2894 m.

Genus Terebellides Sars, emended by Sch��ller and Hutchings 2013 Type species: Terebellides stroemii Sars, 1835 Diagnosis. Trichobranchidae with compact prostomium fused to free frontal edge of the peristomium. Peristomium forming lips, upper lip typically hidden, lower lip expanded. Branchial stems fused, branchiae forming single, lamellate structure on mid-dorsum, made up of 1 to 4 lobes, sometimes an anterior prolongation of lobes (fifth lobe) present. Eyespots absent. Lateral lobes absent. Thorax with 18 pairs of notopodia from segment III and neuropodia from segments VII (chaetiger 5) or segment VIII (chaetiger 6) to pygidium. Notochaetae all capillaries with varying degrees of ornamentation. First, and sometimes second thoracic neuropodia with smooth, geniculate hooks, subsequent thoracic ones with denticulate hooks. Abdominal uncini avicular. Remarks. Parapar et al. (2011) found minute teeth forming a capitium on geniculate chaetae in all Icelandic species (T. stroemii Sars, 1835, T. gracilis Malm, 1874, T. atlantis Williams, 1984 and T. bigeniculatus Parapar, Moreira and Helgason, 2011). We consider the characterisation of geniculate chaetae as ���smooth��� in the current diagnosis as doubtful., Published as part of Parapar, Julio, Mikac, Barbara & Fiege, Dieter, 2013, Diversity of the genus Terebellides (Polychaeta: Trichobranchidae) in the Adriatic Sea with the description of a new species, pp. 333-350 in Zootaxa 3691 (3) on pages 334-335, DOI: 10.11646/zootaxa.3691.3.3, http://zenodo.org/record/248600

Terebellides toliman sp.n. Figs 18, 19, 20 Holotype: ANDEEP-SYSTCO, St. 16 - 1, RD (ZMH- 26016) Paratype: ANDEEP-SYSTCO, St. 16 - 1, RD [SEM, stub MI 566 & MI 567] (AM W 38720) Description: (Based on both holotype and paratype) Holotype in two pieces, anterior part 22 mm in length, 4 mm in width, for 16 chaetigers, posterior part 23 mm in length, 2 mm in width, for 37 uncinigerous segments, extreme posterior missing. Body robust, colour preserved pale cream. Head region: Prostomium with fleshy and markedly expanded tentacular membrane with curved glandular slightly folded margins, internal walls, corrugated and glandular. Tentacles numerous, of two kinds: short, uniform in thickness ones and long ones with expanded tips (Figs 18, 19 A–C). Peristomium consisting of an upper lip and compact lower lip. Segment 2, glandular and expanded ventrally, visible ventrally and laterally, dorsally as narrow ring (Fig. 19 C). Branchiae: Stalk stout and short, weakly annulated (Fig. 18). Four branchial lobes, almost completely fused together except for proximal quarter of lobe, without filamentous tips (Fig. 19 B). Anterior two lobes largest, with compact numerous lamellae (Fig. 19 A). Anterior chaetigers: Notopodia from segment 3, only 17 pairs present, (posterior thorax missing, so suggest that 18 originally present). First five notopodia smaller than subsequent ones, first three pairs more ventrally displaced, first chaetiger very small with poorly developed chaetal lobes and chaetae appearing to arise directly from body wall (Figs 18, 19 A). Posterior notopodia more erect than anterior ones, marked from chaetiger 4 onwards. Notochaetae, capillaries, graded in length within fascicle, with inflated thecae (Fig. 19 D). First neuropodia on chaetiger 6, 6 smooth spines, only weakly bent (about 120 °) (Fig. 19 E). Thoracic neuropodia sessile pinnules, but posteriorly become increasingly erect, and on posterior abdominal segments form inverted triangular erect pinnules. Thoracic neuropodia from chaetiger 7 with uncini arranged in several rows (about 3), long shafted, denticulate with long and stout main fang and several multidentate rows of teeth above, not vertically aligned, so providing a dental formulae not possible (Fig. 19 F, G). Abdominal uncini numerous within a torus and with elongate main fang and two to three rows of 4–5 elongate accessory teeth, head with unsorted multiple denticles (Fig. 19 H). Lateral lappets: Present from TC- 1–6, with TC- 1> 2> 3> 4 = 5 Ventral pads: Entire ventrum glandular, individual pads separated by non-glandular intersegmental rings. Nephridial papillae: None visible in holotype, but nephridial pores present, present in paratype on segments 3, 5, 6, 7, accentuated by methyl green staining. MG staining pattern of thorax resembles pattern 8 (Figs 2, 20): Anterior ventrum of thorax darkly stained with only narrow white bands between each segment. Between chaetigers 11–14, distinct white bands connecting notopodia (Fig. 20 A). Staining posteriorly not fading, but mid ventral glandular stripe stained as well as neuropodial tori (Fig. 20 B), lateral margins of branchiae also stained. Pygidium: Unknown. Remarks: Terebellides toliman sp.n., is characterised by four pairs of branchiae partially fused along their length, with filamentous tips absent, composed of densely packed lamellae, with lateral lappets continuing until thoracic chaetiger 6 and geniculate hooks weakly bent. This new species most closely resembles T. canopus sp.n., (this paper) but can be separated by the shape of the geniculate hooks. Other species with four branchial lobes, partially fused, and densely packed lamellae include T. horikoshii Imajima & Williams, 1985 and T. japonica Moore, 1903, which both differ from T. toliman sp.n., by having lateral lappets until chaetiger 5 only. Terebellides horikoshii in addition has notopodia of chaetigers 1 and 2 well developed whereas in T. toliman sp.n., they are poorly developed. For details on other species see the key. Another distinguishing character is that this species has reached a much greater size than any other species described, and is the only species collected on the one shelf station in this paper or by Schüller and Hutchings (2012). Habitat: Eastern Weddell Sea shelf in 486– 488 m. Known only from type locality. Etymology: The specific name toliman refers to the brightest star in the Centaurus, it is the third brightest star in the sky and the closest star to the Sun.

Key to the Terebellides species from North East Atlantic and Mediterranean 1 Geniculate acicular chaetae on thoracic CH 6............................................................... 2 - Geniculate acicular chaetae on thoracic CH 5 and CH 6........................................... T. bigeniculatus 2 Thoracic CH 1 to CH 4 ventrally whitish............................................................ T. gracilis - Thoracic CH 1 to CH 4 of same ventral colouration as following................................................ 3 3 CH 1 notopodia and notochaetae longer than following................................... T. mediterranea spec. nov. - CH 1 notopodia and notochaetae similar or shorter than following.............................................. 4 4 Branchial lobes moderately fused; a large species (up to 50 mm long).................................... T. stroemii - Branchial lobes free; a small species (less than 20 mm long)............................................ T. atlantis, Published as part of Parapar, Julio, Mikac, Barbara & Fiege, Dieter, 2013, Diversity of the genus Terebellides (Polychaeta: Trichobranchidae) in the Adriatic Sea with the description of a new species, pp. 333-350 in Zootaxa 3691 (3) on page 345, DOI: 10.11646/zootaxa.3691.3.3, http://zenodo.org/record/248600

Terebellides mira sp.n. Figs 9, 10, 11 Holotype: ANDEEP II, St. 133 - 5, GKG [drawing, MG photo] (ZMH- 26009) Paratype: ANDEEP II, St. 133 - 5, GKG [MG photo, SEM, stub MI 539 & MI 540] (AM W 38719) Description: (Based on both holotype and paratype) Holotype 15 mm in length, 1 mm in width, complete with 28 abdominal chaetigers (Fig. 9). Head region: Tentacular membrane largely expanded, horseshoe shaped. Lower lip rectangular, expanded, but not distinctly folded upwards. Tentacles only short and simple on the outer margins of the tentacular membrane, minute papillae apparent on tentacular membrane with MG staining. Branchiae: Branchial lobes free from each other, lamellae broad, loose, only few present, with filamentous tips. Posterior branchial lobes missing. Fifth branchial lobe absent. Annulation of branchial stem present, stem very long, longer than actual branchial lobe (Figs 9, 10 A, B, D, 11). Anterior chaetigers: Notopodia from segments 3���20, 18 pairs, all notopodia of similar size (Fig. 10 A). Notochaetae, capillaries, graded lengths within fascicle with slightly inflated thecae (Fig. 10 E, F). First neuropodia on thoracic segment 8 (chaetiger 6) with geniculate hooks, about 7 per side, strongly protruding, declining in size within a torus from dorsal to ventral (Fig. 10 G), curved with inflated bases and short pointed tips, base of curve with minute teeth. Subsequent neurochaetae long handled hooks with multiple teeth above a main fang in thoracic segments, and abdominal uncini numerous within a torus and with elongate hooks, main fang completely covered by numerous elongate accessory teeth (Fig. 10 H). Lateral lappets: Present from TC- 1���7, with TC- 1 = 3> 2 = 4> 5 = 6 = 7 or TC- 1 = 2 5 Remarks: Terebellides mira sp.n., is characterised by having branchial lobes completely free of each other, all notopodia of similar size and lateral lappets on chaetiger 1���7 and a large number of geniculate hooks on chaetiger 6. Terebellides mira sp.n., belongs to a group of Terebellides which have the first thoracic chaetiger only slightly smaller than subsequent chaetigers but with distinct notopodial lobe present and branchial lamellae few in number and loosely packed (Terebellides lobatus Hartman & Fauchald, 1971, Terebellides diva Sch��ller & Hutchings, 2012 and Terebellides gingko Sch��ller & Hutchings, 2012), but can be distinguished from these species by having filamentous tips to the branchial lobes and lateral lappets to thoracic chaetiger 7. For more details see the key. Habitat: Western Weddell Sea upper continental slope in 1166 m. Known only from type locality. Etymology: The specific name mira refers to the first variable star ever discovered in the constellation Cetus which represents the Sea Monster and was discovered in 1596 by David Fabricius., Published as part of Sch��ller, Myriam & Hutchings, Pat, 2013, New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species, pp. 1-45 in Zootaxa 3619 on pages 16-19, DOI: 10.11646/zootaxa.3619.1.1, http://zenodo.org/record/219061, {"references":["Hartman, O. & Fauchald, K. (1971) Deep-water benthic polychaetous annelids off New England to Bermuda and other North Atlantic areas. Part II. Allan Hancock Monographs in Marine Biology, 6, 1 - 327, 34 plates.","Schuller, M. & Hutchings, P. A. (2012) New species of Terebellides (Polychaeta: Trichobranchidae) indicate long-distance dispersal between western South Atlantic deep-sea basins. Zootaxa, 3254, 1 - 31."]}

Terebellides sp. B Figs 23, 24 Material examined: DZMB-HH 6071, ANDEEP I, St. 46 - 5, GKG (ZMH- 26013) Description: Single specimen 5 mm in length, 5 mm in width, complete with 18 thoracic chaetigers and 22 abdominal uncinigers. Head region: Tentacular membrane compact, but expanded and folded. Lower lip rectangular, distinctly smaller compared to tentacular membrane. Tentacles short simple ones on outer margins of tentacular membrane and longer ones with expanded tips present (Fig. 23). Branchiae: Branchial lobes lost. Annulation of branchial stem not determinable. Anterior chaetigers: First notopodial chaetiger reduced in size with chaetae more or less originating from body wall. Geniculate hooks: Present on TC- 6 (segment 8) only, sharply bent. Lateral lappets: Present from TC- 1���6 or - 7, with TC- 1 = 2 = 3> 4 Remarks: The species differs from all other species described from the region by having a stout lower lip which is short and rectangular and very inconspicuous compared to other known species of Terebellides. Habitat: Drake Passage, in 2894 m., Published as part of Sch��ller, Myriam & Hutchings, Pat, 2013, New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species, pp. 1-45 in Zootaxa 3619 on page 30, DOI: 10.11646/zootaxa.3619.1.1, http://zenodo.org/record/219061

Terebellides rigel sp.n. Figs 12, 13, 14 Holotype: ANDEEP III, St. 78 - 9, EBS (ZMH- 26023) Paratypes: ANDEEP III, St. 121 - 7, AGT [drawing, MG photo] (AM W 39660); ANDEEP III, St. 78 - 9, EBS (3 specimens, ZMH- 26021, ZMH- 26022, ZMH- 26024); ANDEEP III, St. 80 - 9, EBS (ZMH- 26025); ANDEEP III, St. 142 - 5, EBS (2 specimens, AM W 39661, AM W 39662); ANDEEP III, St. 142 - 5, EBS [SEM, stub MI 495] (AM W 38715) Description: (Based on both holotype and paratypes) Holotype 6 mm in length, 1 mm in width, posteriorly incomplete with 18 chaetigers, gravid, body cavity with oocytes. Paratypes ranging in length from 4–6 mm and 0.2–1.0 mm in width, all posteriorly incomplete, all with thorax complete but with only 0–5 abdominal segments. Head region: Tentacular membrane compact, with little expansion. Lower lip rectangular, only laterally slightly expanded (Figs 12, 13 A). Tentacles only short simple ones present on outer margins of tentacular membrane (Fig. 13 A, B). Branchiae: Anterior branchial lobes free from each other, lamellae broad, loose, only few present, with filamentous tips (Figs 12 A, 13 B, D). Dense ciliary fields between each of lamellae (Fig. 13 C, D). Posterior branchial lobes distinctly smaller than anterior lobes. Fifth branchial lobe absent. Annulation of branchial stem not visible. Anterior chaetigers: Notopodia from segments 3–20, 18 pairs. Notopodia of first and second chaetiger reduced and not horizontally aligned, those of chaetiger 2 more dorsal, chaetae appearing to arise directly from body wall (Fig. 13 A). Subsequent chaetigers with well developed notopodia increasing in size posteriorly and inserted more ventrally with pre- and post chaetal lobes similar in length. Notochaetae, fine capillaries with long extended tips (Fig. 13 E, F), shaft with expanded thecae (Fig. 13 F), arranged in two tiers, long tier with about five chaetae and short tier with four (Fig. 13 F). Neuropodia from segment 8 (chaetiger 6) present on all subsequent segments (all material posteriorly incomplete). Neurochaetae of chaetiger 6 sharply curved geniculate hooks with long, extended tips, five present (Fig. 13 G) although one represented by stub, surface of hooks appears structured. Subsequent neuropodia with long shafted denticulate hooks with main fang and several multidentate rows of teeth above, not vertically aligned, so providing a dental formulae not possible (Fig. 13 H). Lateral lappets: Present on thoracic chaetigers 1—4, possibly to TC- 6, with TC- 1> 2> 3> 4> 5 = 6. Ventral pads: Ventrum of thoracic segments glandular with anterior margins of segments elevated, especially marked on chaetigers 1–7, continue laterally to form lateral lappets on chaetigers 1–4 (Fig. 13 E). Nephridial papillae: Present on segments 3, 4, 6, 7. MG staining pattern 1 (Figs 2, 14): With distinctly solid anterior part and broad stripes in median and posterior segments. White band, pronounced anterior margins and neuropodial staining missing, notopodial staining only weak if present (Fig. 14). Pygidium: Unknown. Remarks: Terebellides rigel sp.n., is characterised by having branchial lobes free from each other and each with few lamellae, distinct lateral lappets from chaetigers 1–4 decreasing in size posteriorly to chaetiger 6, first neuropodia with geniculate hooks only and all subsequent neuropodia with a single row of long handled hooks with strongly denticulate heads. This species can easily be separated from two widely distributed species in the region T. kerguelensis McIntosh, 1885 and T. longicaudatus Hessle, 1917 which are both characterised in having five branchial lobes and each with numerous lamellae in contrast to T. rigel sp.n. This new species belongs to a group of species with branchial lobes with few loosely packed lamellae (Terebellides banalis Schüller & Hutchings, 2012, Terebellides sepultura Garraffoni & Lana, 2003, Terebellides distincta Williams, 1984, and Terebellides irinae, Gagaev, 2009) but it can be distinguished from these by the presence of lateral lappets until thoracic chaetiger 6. For more details see the key. Habitat: Weddell Sea, lower continental slope to abyss in 2182–3403 m. Known only from type locality. Etymology: The specific name rigel refers to one of the brightest stars of Orion, the most famous seasonal constellation.

Terebellides crux sp.n. Figs 6, 7, 8 Holotype: ANDEEP III, St. 121 - 11, EBS (ZMH- 26027) Paratypes: ANDEEP II, St. 132 - 6, GKG [drawing, MG photo] (ZMH- 26008); ANDEEP III, 110 - 8, EBS (ZMH- 26026); ANDEEP III, St. 121 - 11, EBS (5 specimens, AM W 39656, AM W 39996, AM W 39657, AM W 39658, AM W 39659); ANDEEP III, St. 121 - 11, EBS [SEM, stub MI 496] (AM W 38714); ANDEEP III, St. 16 - 10, EBS (ZMH- 26028); ANDEEP III, St. 78 - 9, EBS (2 specimens, ZMH- 26029, ZMH- 26030) Description: (Based on both holotype and paratypes) Holotype, 7 mm in length, 0.5 mm in width, posteriorly incomplete. Paratypes ranging from 6–8 mm in length, 0.5–1.0 mm in width, majority posteriorly incomplete. Complete specimens with up to 35 abdominal chaetigers. Head region: Tentacular membrane compact, not greatly expanded. Lower lip rectangular, distinctly folded upwards with smooth rim (Fig. 6). Tentacles only short, thick, wrinkled, present on outer margins of tentacular membrane in some specimens (Fig. 6), others with long numerous tentacles of two types (simple and with expanded tips) (Fig. 7 A–C, E). Branchiae: Lobes lost with only stem present on holotype, but part of lobes present in paratypes (Fig. 7 A). Thick wrinkled stem with lobes with few short compact lamellae (Fig. 7 A–C), ciliary fields present between lamellae (Fig. 7 D). Lobes free from each other, all of similar size, with distinct filamentous tip (Fig. 7 B, C). Anterior chaetigers: Notopodia from segment 3, 18 pairs. Chaetiger 1 reduced in size with chaetae more or less originating from body wall and more dorsally aligned than subsequent ones (Fig. 7 A, F). Following chaetigers with elongate rectangular notopodia with elongate capillary notochaetae, numbering 6–8 per podium arranged in two tiers (Fig. 7 A, F); capillaries with fine pointed tips, thecae with flared tips (Fig. 7 F). Neuropodia from segment 7 (chaetiger 5). First neuropodia with 3 curved hooks with extended pointed tips (Fig. 7 G). Segment 8 (chaetiger 6) with 4 curved hooks (Fig. 7 G). Subsequent neuropodia with 3 or more long shafted denticulate hooks with main fang and several multidentate rows of teeth above, not vertically aligned (Fig. 7 H) so providing a dental formulae not possible. Lateral lappets: Present from thoracic segments 1–6, with thoracic chaetigers TC- 1 = 2 4 = 5 = 6 (Figs 6, 7 E). Ventral pads: Ventrum glandular, segments 2 and 3 narrow, width of ventrum increasing on segments 4-6, with anterior margins expanded forming thickened membraneous collars (Fig. 7 E). Subsequent segments narrow ventrally with anterior margins forming thickened collars (Fig. 7 E). Nephridial papillae: Present on segments 3, 6, 7 (Fig. 7 A). MG staining pattern 1 (Figs 2, 8): With anterior segments solidly stained and striped median thoracic segments. Distinct white bands or pronounced anterior margins of segments lacking; noto- and neuropodia stain. Pygidium: Rounded blunt cone without appendages. Remarks: This new species is characterised by having the first two rows of neuropodia with geniculate hooks starting on chaetiger 5, a character only known for three other species of the genus: T. biaciculata Hartmann- Schröder, 1992, T. bigeniculatus Parapar, Moreira & Helgalson, 2011 and T. intoshi Caullery, 1915. According to Imajima and Williams (1985) in T. intoshi geniculate hooks are present in chaetigers 6 and 7 as opposed to chaetigers 5 and 6 in the other three species, this trait was however not mentioned in the original description by Caullery (1915). Terebellides crux sp.n., clearly differs from T. biaciculata and T. bigeniculatus by its branchial lobes, which are free and all of equal length in T. crux sp.n., and partially fused with distinctly larger anterior lobes than posterior lobes in T. biaciculata and T. bigeniculatus. All other described species of Terebellides have neuropodia starting in chaetiger 6 and only the first neuropodia with geniculate hooks, the remaining with long shafted denticulate hooks. This has necessitated the modification of the generic diagnosis which we have preferred to do rather than erecting a new genus at this stage. Habitat: South eastern South Atlantic and Weddell Sea deep waters in 2086–4720 m. Etymology: The species name crux is an alternative name for the Southern Cross.

Terebellides rigel sp.n. Figs 12, 13, 14 Holotype: ANDEEP III, St. 78 - 9, EBS (ZMH- 26023) Paratypes: ANDEEP III, St. 121 - 7, AGT [drawing, MG photo] (AM W 39660); ANDEEP III, St. 78 - 9, EBS (3 specimens, ZMH- 26021, ZMH- 26022, ZMH- 26024); ANDEEP III, St. 80 - 9, EBS (ZMH- 26025); ANDEEP III, St. 142 - 5, EBS (2 specimens, AM W 39661, AM W 39662); ANDEEP III, St. 142 - 5, EBS [SEM, stub MI 495] (AM W 38715) Description: (Based on both holotype and paratypes) Holotype 6 mm in length, 1 mm in width, posteriorly incomplete with 18 chaetigers, gravid, body cavity with oocytes. Paratypes ranging in length from 4���6 mm and 0.2���1.0 mm in width, all posteriorly incomplete, all with thorax complete but with only 0���5 abdominal segments. Head region: Tentacular membrane compact, with little expansion. Lower lip rectangular, only laterally slightly expanded (Figs 12, 13 A). Tentacles only short simple ones present on outer margins of tentacular membrane (Fig. 13 A, B). Branchiae: Anterior branchial lobes free from each other, lamellae broad, loose, only few present, with filamentous tips (Figs 12 A, 13 B, D). Dense ciliary fields between each of lamellae (Fig. 13 C, D). Posterior branchial lobes distinctly smaller than anterior lobes. Fifth branchial lobe absent. Annulation of branchial stem not visible. Anterior chaetigers: Notopodia from segments 3���20, 18 pairs. Notopodia of first and second chaetiger reduced and not horizontally aligned, those of chaetiger 2 more dorsal, chaetae appearing to arise directly from body wall (Fig. 13 A). Subsequent chaetigers with well developed notopodia increasing in size posteriorly and inserted more ventrally with pre- and post chaetal lobes similar in length. Notochaetae, fine capillaries with long extended tips (Fig. 13 E, F), shaft with expanded thecae (Fig. 13 F), arranged in two tiers, long tier with about five chaetae and short tier with four (Fig. 13 F). Neuropodia from segment 8 (chaetiger 6) present on all subsequent segments (all material posteriorly incomplete). Neurochaetae of chaetiger 6 sharply curved geniculate hooks with long, extended tips, five present (Fig. 13 G) although one represented by stub, surface of hooks appears structured. Subsequent neuropodia with long shafted denticulate hooks with main fang and several multidentate rows of teeth above, not vertically aligned, so providing a dental formulae not possible (Fig. 13 H). Lateral lappets: Present on thoracic chaetigers 1���4, possibly to TC- 6, with TC- 1> 2> 3> 4> 5 = 6. Ventral pads: Ventrum of thoracic segments glandular with anterior margins of segments elevated, especially marked on chaetigers 1���7, continue laterally to form lateral lappets on chaetigers 1���4 (Fig. 13 E). Nephridial papillae: Present on segments 3, 4, 6, 7. MG staining pattern 1 (Figs 2, 14): With distinctly solid anterior part and broad stripes in median and posterior segments. White band, pronounced anterior margins and neuropodial staining missing, notopodial staining only weak if present (Fig. 14). Pygidium: Unknown. Remarks: Terebellides rigel sp.n., is characterised by having branchial lobes free from each other and each with few lamellae, distinct lateral lappets from chaetigers 1���4 decreasing in size posteriorly to chaetiger 6, first neuropodia with geniculate hooks only and all subsequent neuropodia with a single row of long handled hooks with strongly denticulate heads. This species can easily be separated from two widely distributed species in the region T. kerguelensis McIntosh, 1885 and T. longicaudatus Hessle, 1917 which are both characterised in having five branchial lobes and each with numerous lamellae in contrast to T. rigel sp.n. This new species belongs to a group of species with branchial lobes with few loosely packed lamellae (Terebellides banalis Sch��ller & Hutchings, 2012, Terebellides sepultura Garraffoni & Lana, 2003, Terebellides distincta Williams, 1984, and Terebellides irinae, Gagaev, 2009) but it can be distinguished from these by the presence of lateral lappets until thoracic chaetiger 6. For more details see the key. Habitat: Weddell Sea, lower continental slope to abyss in 2182���3403 m. Known only from type locality. Etymology: The specific name rigel refers to one of the brightest stars of Orion, the most famous seasonal constellation., Published as part of Sch��ller, Myriam & Hutchings, Pat, 2013, New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species, pp. 1-45 in Zootaxa 3619 on pages 19-22, DOI: 10.11646/zootaxa.3619.1.1, http://zenodo.org/record/219061, {"references":["McIntosh, W. C. (1885) Report on the Annelida Polychaeta collected by H. M. S. Challenger during the years 1873 - 1876. Report on the Scientific Results of the Voyage of H. M. S. Challenger during the years 1872 - 76, 12, 1 - 554, plates 1 - 39 a, 1 map.","Hessle, C. (1917) Zur Kenntnis der terebellomorphen Polychaeten. Zoologiska bidrag fran Uppsala 5, 39 - 258, plates I - V.","Schuller, M. & Hutchings, P. A. (2012) New species of Terebellides (Polychaeta: Trichobranchidae) indicate long-distance dispersal between western South Atlantic deep-sea basins. Zootaxa, 3254, 1 - 31.","Garraffoni, A. R. S. & Lana, P. C. (2003) Species of Terebellides (Polychaeta, Terebellidae, Trichobranchinae) from the Brazilian coast. Iheringia, 93 (4), 355 - 363. http: // dx. doi. org / 10.1590 / S 0073 - 47212003000400002","Williams, S. J. (1984) The status of Terebellides stroemii (Polychaeta; Trichobranchidae) as a cosmopolitan species, based on a worldwide morphological survey, including description of new species. In: Hutchings, PA (Ed). Proceedings of the First International Polychaete Conference, Sydney, Australia, 1984. The Linnean Society of New South Wales: Sydney, 118 - 142.","Gagaev, S. Y. (2009) Terebellides irinae sp. n., a new species of Terebellides (Polychaeta: Terebellidae) from the Arctic basin. Biologiya Morya, 35 (6), 420 - 424."]}

Terebellides toliman sp.n. Figs 18, 19, 20 Holotype: ANDEEP-SYSTCO, St. 16 - 1, RD (ZMH- 26016) Paratype: ANDEEP-SYSTCO, St. 16 - 1, RD [SEM, stub MI 566 & MI 567] (AM W 38720) Description: (Based on both holotype and paratype) Holotype in two pieces, anterior part 22 mm in length, 4 mm in width, for 16 chaetigers, posterior part 23 mm in length, 2 mm in width, for 37 uncinigerous segments, extreme posterior missing. Body robust, colour preserved pale cream. Head region: Prostomium with fleshy and markedly expanded tentacular membrane with curved glandular slightly folded margins, internal walls, corrugated and glandular. Tentacles numerous, of two kinds: short, uniform in thickness ones and long ones with expanded tips (Figs 18, 19 A���C). Peristomium consisting of an upper lip and compact lower lip. Segment 2, glandular and expanded ventrally, visible ventrally and laterally, dorsally as narrow ring (Fig. 19 C). Branchiae: Stalk stout and short, weakly annulated (Fig. 18). Four branchial lobes, almost completely fused together except for proximal quarter of lobe, without filamentous tips (Fig. 19 B). Anterior two lobes largest, with compact numerous lamellae (Fig. 19 A). Anterior chaetigers: Notopodia from segment 3, only 17 pairs present, (posterior thorax missing, so suggest that 18 originally present). First five notopodia smaller than subsequent ones, first three pairs more ventrally displaced, first chaetiger very small with poorly developed chaetal lobes and chaetae appearing to arise directly from body wall (Figs 18, 19 A). Posterior notopodia more erect than anterior ones, marked from chaetiger 4 onwards. Notochaetae, capillaries, graded in length within fascicle, with inflated thecae (Fig. 19 D). First neuropodia on chaetiger 6, 6 smooth spines, only weakly bent (about 120 ��) (Fig. 19 E). Thoracic neuropodia sessile pinnules, but posteriorly become increasingly erect, and on posterior abdominal segments form inverted triangular erect pinnules. Thoracic neuropodia from chaetiger 7 with uncini arranged in several rows (about 3), long shafted, denticulate with long and stout main fang and several multidentate rows of teeth above, not vertically aligned, so providing a dental formulae not possible (Fig. 19 F, G). Abdominal uncini numerous within a torus and with elongate main fang and two to three rows of 4���5 elongate accessory teeth, head with unsorted multiple denticles (Fig. 19 H). Lateral lappets: Present from TC- 1���6, with TC- 1> 2> 3> 4 = 5 Remarks: Terebellides toliman sp.n., is characterised by four pairs of branchiae partially fused along their length, with filamentous tips absent, composed of densely packed lamellae, with lateral lappets continuing until thoracic chaetiger 6 and geniculate hooks weakly bent. This new species most closely resembles T. canopus sp.n., (this paper) but can be separated by the shape of the geniculate hooks. Other species with four branchial lobes, partially fused, and densely packed lamellae include T. horikoshii Imajima & Williams, 1985 and T. japonica Moore, 1903, which both differ from T. toliman sp.n., by having lateral lappets until chaetiger 5 only. Terebellides horikoshii in addition has notopodia of chaetigers 1 and 2 well developed whereas in T. toliman sp.n., they are poorly developed. For details on other species see the key. Another distinguishing character is that this species has reached a much greater size than any other species described, and is the only species collected on the one shelf station in this paper or by Sch��ller and Hutchings (2012). Habitat: Eastern Weddell Sea shelf in 486��� 488 m. Known only from type locality. Etymology: The specific name toliman refers to the brightest star in the Centaurus, it is the third brightest star in the sky and the closest star to the Sun., Published as part of Sch��ller, Myriam & Hutchings, Pat, 2013, New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species, pp. 1-45 in Zootaxa 3619 on pages 25-28, DOI: 10.11646/zootaxa.3619.1.1, http://zenodo.org/record/219061, {"references":["Imajima M. & Williams, S. J. (1985) Trichobranchidae (Polychaeta) chiefly from the Sagami and Suruga Bays, collected by the R / V Tansei-Maru (cruises KT- 65 - 76). Bulletin of the National Science Museum, Tokyo, 11 (1), 7 - 18, 5 figures.","Moore, J. P. (1903) Polychaeta from the coastal slope of Japan and from Kamchatka and Bering Sea. Proceedings of the Academy of Natural Sciences, Philadelphia, 55, 401 - 490, plate 23 - 27.","Schuller, M. & Hutchings, P. A. (2012) New species of Terebellides (Polychaeta: Trichobranchidae) indicate long-distance dispersal between western South Atlantic deep-sea basins. Zootaxa, 3254, 1 - 31."]}

Terebellides gracilis (Malm, 1874) (Figures 2���4, 12 b, 13) Terebellides gracilis Malm 1874: 100. Terebellides gracilis ���Hansson 1998: 77. Parapar et al. 2011: 11, Figs 8���10, 13 c. Terebellides williamsae ���Jirkov 1989: 124. Jirkov 2001: 529, Figs 1���4. Material examined. A total of 23 specimens were examined (27.4% of the total Terebellides specimens collected) all from station SJ 0 0 7: 27.02. 2003 (PMR- 14550, 2 specs.; PMR- 14551, 1 spec.; PMR- 14552, 1 spec. on SEM stub; PMR- 14553, 1 spec. on SEM stub); 28.05. 2003 (PMR- 14554, 2 specs.; PMR- 14555, 3 specs); 12.08. 2003 (MNCN 16.01/ 14714, 1 spec.; MNCN 16.01/ 14715, 2 specs.); 23.01.0 4 (2 specs.) (coll. BM); 30.08. 2004 (2 specs.) (coll. BM); 0 2.12. 2004 (PMR- 14556, 3 specs.; PMR- 14557, 3 specs.). Description of Adriatic Sea specimens. Complete specimens range from 12 to 18 mm in length and 1.2 to 0.7 mm in width; body tapering posteriorly with segments becoming increasingly shorter and crowded towards pygidium. Prostomium compact; tentacular membrane surrounding mouth, with many long buccal tentacles with expanded tips. SGI forming an expanded structure below tentacular membrane. Lateral lappets on SGIII���VIII (CH 1���6) (Fig. 2 a) being larger and continuing ventrally on SG III to VI, declining in size posteriorly. No conspicuous dorsal rounded projection in anterior chaetigers or oval-shaped glandular region in CH 3. Branchiae arising as single structure from SGIII, consisting of single stalked structure located mid-dorsally (Figs 2 a, 3 a) made up of two posterior pairs of lobes fused along less than one third of their length; lower pair slightly shorter than upper pair. Pointed projection of posterior region of lobes present in lower lobes. Anterior branchial projection (fifth lobe) not conspicuous. Both sides of branchial lamellae provided with several parallel bent rows of cilia and outer tufts of cilia (Figs 2 b, c; 3 b). Branchial lamellae less tightly packed than in the other two Adriatic species. Eighteen pairs of thoracic notopodia (SGIII���XX). Notopodia and notochaetae of first chaetiger not visible in some specimens (Fig. 2 a, d); chaetae present only in larger specimens but much shorter than on subsequent notopodia (Fig. 3 a). Neuropodia present as sessile pinnules from CH 6 (SGVIII) to pygidium and provided with uncini in single rows throughout (Fig. 4 a). The absence of notochaetae in first chaetiger in most specimens may lead to the erroneous observation that first neuropodium is located on CH 5 instead of CH 6. First thoracic neuropodia provided with 5 ��� 7 sharply bent, acute tipped, geniculate acicular hooks (Fig. 3 c). Minute teeth forming a capitium on geniculate chaetae not observed. Second and all subsequent thoracic neuropodia with up to 7���10 uncini per torus (Fig. 4 a). Uncini provided with long shafted denticulate hooks with 2 ��� 4 teeth above main fang surmounted by 4 ��� 5 shorter teeth and an upper crest of several smaller denticles (Fig. 4 b), dental formula MF: 2��� 4: 4���5:���. Between 30���32 abdominal neuropodia as erect pinnules provided with about 22 uncini per torus (Fig. 4 c); uncini with 5 teeth above main fang surmounted by a crest of 4���5 shorter teeth and a variable number of smaller teeth (Fig. 4 d); dental formula MF: 5: 4���5:���. Pygidium blunt, funnel-like depression. One large, button-hole like nephridial opening on each notopodium of CH 4 and CH 5 (Fig. 3 d). MG staining pattern 2 (Figs 12 b, 13 a): compact green colouration in CH 1 ��� 10, quickly fading in following segments. CH 1 ��� 3 slightly and CH 4 much less stained than anterior and posterior ones. Colour in alcohol pale brown with four anterior thoracic chaetigers ventrally white (Fig. 13 b). Remarks. Hansson (1998) proposed to recover T. gracilis from the synonymy of T. stroemii due to the presence of four white ventrally colored thoracic segments (SGIII���VI; CH 1���4) in T. gracilis. Following this opinion, Parapar et al. (2011) redescribed the species from material collected in the BIOICE project in Iceland and proposed also T. williamsae Jirkov, 1989 as a junior synonym. Terebellides gracilis was until now found in the Norwegian and Barents Seas (Malm 1874; Jirkov 1989) and Iceland (Parapar et al. 2011). Our Mediterranean records extend the range of the species into quite different ecological conditions compared to those where it was recorded so far. However, the finding of this species in the Northern Adriatic Sea is not so surprising and it supports the strong boreal affinity of this region, as well as its ecological and biogeographical similarities with the North Atlantic, which have previously been documented (Bianchi et al. 2004; Boero & Bonsdorff 2007). The Adriatic Sea is the northernmost Mediterranean region and together with the Gulf of Lions and the Northern Aegean Sea the coldest sector of the Mediterranean. It is geomorphologically, hydrographically and biogeographically a peculiar Mediterranean region with lower average temperatures that allow the presence of a specific flora and fauna with cold water affinities (Mikac & Musco 2010). Our research showed that Adriatic specimens of T. gracilis are slightly shorter than boreo-arctic specimens. This feature could be a morphological variability due to the different ecological conditions in which specimens are living. Further molecular analyses could possibly assist to clarify this phenomenon. Adriatic specimens are slightly shorter (12���18 vs 10���25 mm) and have less abdominal chaetigers (30���32 vs. about 43) and less uncini (22 vs. 45) than boreo-arctic specimens. Also, the chaetae from first thoracic chaetiger are less conspicuous than in Icelandic specimens and the dental formula of thoracic uncini differs, with two teeth surmounting the main fang in North Atlantic specimens (MF: 2: 5:���) but 2���4 in Adriatic ones (MF: 2���4: 4���5:���). The staining pattern coincides with one of the Icelandic specimens although Parapar et al. (2011) erroneously reported pattern 4 for those specimens instead of 2 (Parapar et al. 2011, page 19, Table 1). Habitat. Found at shelf depths (385���390 m) in Scandinavian and Russian waters (Jirkov, 1989; 2001; Hansson, 1998). North and South coast of Iceland; 68 to 2076 meters depth (Parapar et al., 2011). In the Adriatic Sea the species was found on the offshore station in silty sand at 31 m. Distribution. Norwegian Sea and Barents Sea (Malm 1874; Jirkov 1989); Iceland (Parapar et al. 2011) and Adriatic Sea. Our finding in the Adriatic Sea represents the first record of this species in the Mediterranean Sea, and considerably expands the southern boundary of this species., Published as part of Parapar, Julio, Mikac, Barbara & Fiege, Dieter, 2013, Diversity of the genus Terebellides (Polychaeta: Trichobranchidae) in the Adriatic Sea with the description of a new species, pp. 333-350 in Zootaxa 3691 (3) on pages 335-338, DOI: 10.11646/zootaxa.3691.3.3, http://zenodo.org/record/248600

Terebellides mira sp.n. Figs 9, 10, 11 Holotype: ANDEEP II, St. 133 - 5, GKG [drawing, MG photo] (ZMH- 26009) Paratype: ANDEEP II, St. 133 - 5, GKG [MG photo, SEM, stub MI 539 & MI 540] (AM W 38719) Description: (Based on both holotype and paratype) Holotype 15 mm in length, 1 mm in width, complete with 28 abdominal chaetigers (Fig. 9). Head region: Tentacular membrane largely expanded, horseshoe shaped. Lower lip rectangular, expanded, but not distinctly folded upwards. Tentacles only short and simple on the outer margins of the tentacular membrane, minute papillae apparent on tentacular membrane with MG staining. Branchiae: Branchial lobes free from each other, lamellae broad, loose, only few present, with filamentous tips. Posterior branchial lobes missing. Fifth branchial lobe absent. Annulation of branchial stem present, stem very long, longer than actual branchial lobe (Figs 9, 10 A, B, D, 11). Anterior chaetigers: Notopodia from segments 3–20, 18 pairs, all notopodia of similar size (Fig. 10 A). Notochaetae, capillaries, graded lengths within fascicle with slightly inflated thecae (Fig. 10 E, F). First neuropodia on thoracic segment 8 (chaetiger 6) with geniculate hooks, about 7 per side, strongly protruding, declining in size within a torus from dorsal to ventral (Fig. 10 G), curved with inflated bases and short pointed tips, base of curve with minute teeth. Subsequent neurochaetae long handled hooks with multiple teeth above a main fang in thoracic segments, and abdominal uncini numerous within a torus and with elongate hooks, main fang completely covered by numerous elongate accessory teeth (Fig. 10 H). Lateral lappets: Present from TC- 1–7, with TC- 1 = 3> 2 = 4> 5 = 6 = 7 or TC- 1 = 2 5 Ventral pads: Ventrum glandular to chaetiger 11, distinct raised ridges extend across the ventrum with elevated anterior margins. Nephridial papillae: Present on segments 3, 4, 6, 7, elongate papillae posterior dorsal to notopodia. MG staining pattern 9 (Figs 2, 11): Anterior solidly stained with thin white “glandular” region lateral in segment 5 (TC- 3), TC- 4 more solidly stained than all others, striped from TC- 5 on, TC- 12–16 only with very fine stripe. White bands may be present in TC- 9–11, anterior margins not pronounced. Neuropodia not stained, notopodia can stain initially and fade quicker than remaining body. Pygidium: 2 blunt lateral papillae (Fig. 9 B). Remarks: Terebellides mira sp.n., is characterised by having branchial lobes completely free of each other, all notopodia of similar size and lateral lappets on chaetiger 1–7 and a large number of geniculate hooks on chaetiger 6. Terebellides mira sp.n., belongs to a group of Terebellides which have the first thoracic chaetiger only slightly smaller than subsequent chaetigers but with distinct notopodial lobe present and branchial lamellae few in number and loosely packed (Terebellides lobatus Hartman & Fauchald, 1971, Terebellides diva Schüller & Hutchings, 2012 and Terebellides gingko Schüller & Hutchings, 2012), but can be distinguished from these species by having filamentous tips to the branchial lobes and lateral lappets to thoracic chaetiger 7. For more details see the key. Habitat: Western Weddell Sea upper continental slope in 1166 m. Known only from type locality. Etymology: The specific name mira refers to the first variable star ever discovered in the constellation Cetus which represents the Sea Monster and was discovered in 1596 by David Fabricius.

Terebellides canopus sp.n. Figs 3, 4, 5 Holotype: ANDEEP III, St. 74 - 6, EBS (ZMH- 26017) Paratypes: ANDEEP III, St. 121 - 10, GKG (ZMH- 26011); ANDEEP III, St. 121 - 10, GKG [drawing] (ZMH- 26012); ANDEEP III, St. 150 - 3, GKG [drawing, MG photo] (AM W 39666); ANDEEP III, St. 150 - 3, GKG [drawing, MG photo, SEM, stub MI 583] (AM W 38717); ANDEEP III, St. 74 - 6, EBS (3 specimens, ZMH- 26018, ZMH- 26019, ZMH- 26020); ANDEEP III, St. 150 - 6, EBS [SEM, stub MI 490 & MI 491] (AM W 38718); ANDEEP III, St. 150 - 6, EBS (2 specimens, AM W 39667, AM W 39668); ANDEEP II, St. 46 - 7, EBS (ZMH- 26031). Description: (Based on both holotype and paratypes). Holotype: 12 mm in length, 2 mm in width, posteriorly incomplete with 8 abdominal chaetigers. Paratypes range in length from 4���6 mm in length and 1 to 1.5 mm in width, all posteriorly incomplete, some with a few abdominal chaetigers, majority with only thoracic chaetigers. Head region: Tentacular membrane expanded and folded. Lower lip rectangular, expanded and folded upwards with a smooth rim. Tentacles either only short simple ones present on outer margins of tentacular membrane (Fig. 3 A, B), or numerous long tentacles with expanded tips (Fig. 4 A, D). Branchiae: Branchial lobes fused to about 50 %, lamellae broad, but numerous and compact, without distinct filamentous tips (Figs 3 C, D, 4 A, B). Posterior branchial lobes shorter (about 80 % of anterior ones). Fifth branchial lobe absent. No evidence of ciliary fields between lamellae (Fig. 4 C). Annulation of branchial stem present, stem rather long and flattened (Fig. 3 C). Possibly juvenile branchial development with drop-shaped branchiae arranged at 120 �� angle to each other on one specimen (Figs 3 D, 5 F). Anterior chaetigers: Notopodia from segments 3���20, 18 pairs. First notopodia reduced in size compared to subsequent notopodia with chaetae more or less originating from body wall. Notochaetae, capillaries varying in length within fascicle (Fig. 4 D). Neuropodia present from segment 8, those of TC- 6 (chaetiger 6) geniculate hooks, about 7���9 per side, strongly bent with long extended fine tips (Fig. 4 E). Subsequent neuropodia with long shafted denticulate hooks with main fang and several rows of teeth above, not vertically aligned, so providing a dental formulae not possible (Fig. 4 G, H). Uncini arranged in single rows although may be irregular (Fig. 4 F) so as to appear as arranged in double rows. Abdominal uncini with numerous rows of elongate teeth extending to tip of uncinus covering the main fang (Fig. 4 H). Lateral lappets: Present from TC- 1���7, with TC- 1 = 2 = 3 = 4> 5 7 (Figs 3 A, B, 4 D). Ventral pads: Ventrum of thoracic segments strongly glandular with anterior margins of segments elevated, especially marked on chaetigers 1���4. Nephridial papillae: Present on segments 3, 5, 6, 7, small globular slightly elongate (Fig. 5 E). MG staining pattern 8 (Figs 2, 5): Solid to about TC- 11 or - 12, few subsequent segments with distinct stripes. No distinct white bands or pronounced anterior margins present, noto- and neuropodia stain. Pygidium: Unknown. Remarks: Terebellides canopus sp.n., is characterised by having a lower lip with smooth margin, branchial lobes at least partially fused along their length with lamellae densely packed, a single row of thoracic geniculate hooks and subsequent uncini arranged in single and sometimes in double rows. This new species resembles T. toliman sp.n., (this paper) as it also lacks the 5 th branchial lobe, and branchiae are equipped with numerous branchial lamellae, densely packed, all lobes lacking filamentous tips, but can be easily separated by the shape of the nuchal hooks and by the development of lateral lappets. They are present to the 6 th thoracic chaetiger in T. toliman sp.n., (this paper) and the 7 th in T. canopus sp.n. The geniculate hooks are strongly bent in T. canopus sp.n., and weakly bent in T. toliman sp.n. Other species with partially fused branchial lobes with numerous lamellae include Terebellides californica Williams, 1984, Terebellides horikoshii Imajima & Williams, 1985, and Terebellides japonica Moore, 1903, but these all have lateral lappets only until the 5 th thoracic chaetiger. For further details see the key. Habitat: Known only from the eastern and western Weddell Sea continental slope to upper abyss and the Drake Passage in 1047���2621 m. Etymology: The specific name canopus is the brightest star in the constellation Carina., Published as part of Sch��ller, Myriam & Hutchings, Pat, 2013, New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species, pp. 1-45 in Zootaxa 3619 on pages 9-12, DOI: 10.11646/zootaxa.3619.1.1, http://zenodo.org/record/219061, {"references":["Williams, S. J. (1984) The status of Terebellides stroemii (Polychaeta; Trichobranchidae) as a cosmopolitan species, based on a worldwide morphological survey, including description of new species. In: Hutchings, PA (Ed). Proceedings of the First International Polychaete Conference, Sydney, Australia, 1984. The Linnean Society of New South Wales: Sydney, 118 - 142.","Imajima M. & Williams, S. J. (1985) Trichobranchidae (Polychaeta) chiefly from the Sagami and Suruga Bays, collected by the R / V Tansei-Maru (cruises KT- 65 - 76). Bulletin of the National Science Museum, Tokyo, 11 (1), 7 - 18, 5 figures.","Moore, J. P. (1903) Polychaeta from the coastal slope of Japan and from Kamchatka and Bering Sea. Proceedings of the Academy of Natural Sciences, Philadelphia, 55, 401 - 490, plate 23 - 27."]}

Based on specimens collected during several sampling programmes along the Iranian coast, Persian Gulf, a new species of the genus Terebellides (Polychaeta, Trichobranchidae) is herein described as Terebellides persiae spec. nov. The new species is primarily characterised by the presence of a large dorsal thoracic hump in larger specimens and ciliated papillae on the branchial lamellae. The new species is compared with other taxa belonging to Terebellides described or reported with any of both characters. SEM and micro-CT have been used to study T. persiae spec. nov. and provide several new details on external characters and internal organs, respectively. A key for the identification of the species of Terebellides with dorsal hump is provided.

Terebellides banalis sp. n. Figs 7–9 Etymology: The name refers to the rather plain appearance of the species which lacks the often Terebellides - characteristic expansions of head features and/or anterior segments. Diagnosis: The species is characterized by the well developed second segment that is ventrally even wider than the third, first chaetigerous, segment. The acicular uncini in TC-6 lack a characteristic angle at their bend but rather are cane-shaped. Holotype: Diva 3; st 554; EBS; 26°34.70'S, 35°12.79'W, 4484.7 m (start trawl) to 26°34.87'S, 35°12.79'W, 4477.0 m (gear off ground); 22.07.2009; NW off Rio Grande Rise (ZMH-25947) Paratypes: Diva 3; st 554; EBS; 26°34.70'S, 35°12.79'W, 4484.7 m (start trawl) to 26°34.87'S, 35°12.79'W, 4477.0 m (gear off ground); 22.07.2009; NW off Rio Grande Rise (1 specimen, ZMH-25948) Diva 3; st 561; EBS; 26°34.78'S, 35°13.90'W, 4484.4 m (start trawl) to 26°34.96'S, 35°13.89'W, 4493.0 m (gear off ground); 23.07.2009; NW off Rio Grande Rise (1 specimen, AM W37819.001 [SEM]), Published as part of Schüller, M. & Hutchings, P. A., 2012, New species of Terebellides (Polychaeta: Trichobranchidae) indicate long-distance dispersal between western South Atlantic deep-sea basins, pp. 1-31 in Zootaxa 3254 on page 12

Terebellides concertina sp. n. Figs 13–15 Etymology: The name refers to the shape of the anterior thoracic chaetigers that are narrow but laterally expanded similar to a partially compressed accordion. Diagnosis: The species can be recognized by the first and second segment that are conspicuous laterally, and the lateral lappets which are characterized by distinct lateral extensions rather than by anterior expansions resulting in narrow anterior chaetigers. Holotype: Diva 3; st 534; EBS; 36°0.61'S, 49°1.54'W, 4607.8 m (start trawl) to 36°0.70'S, 49°1.73'W, 4576.1 m (gear off ground); 16.07.2009; Argentine Basin (ZMH-25952) Paratypes: Diva 3; st 534; EBS; 36°0.61'S, 49°1.54'W, 4607.8 m (start trawl) to 36°0.70'S, 49°1.73'W, 4576.1 m (gear off ground); 16.07.2009; Argentine Basin (1 specimen, ZMH-25953 [SEM]) Diva 3; st 533; EBS; 36°0.20'S, 49°1.96'W, 4601.8 m (start trawl) to 36°0.27'S, 49°2.13'W, 4604.0 m (gear off ground); 15.07.2009; Argentine Basin (1 specimen, ZMH-25951) Description: Holotype 20 mm long, 5 mm wide, incomplete, ovigerous. Size of observed specimens varies from 2 mm to about 7 mm, all incomplete. Maximum width up to 2.5 mm. Prostomium with lower lip with folds in lateral regions and anteriorly expanded median region (Fig. 13a, c). Tentacular membrane expanded (Fig. 14a, b), surrounded by buccal tentacles of varying length, simple and with expanded tips (Figs 13a, b, 15a–c). Upper lip hardly visible, mostly covered by lower lip from ventrum. First segment well visible laterally, second segment well visible in ventral and lateral view, barely covered by expanded third segment (Fig. 13a, c). Third segment bearing two distinct longitudinal folds midventrally (Figs 13c, 15a, b). Lateral lappets on segments 3–9 (TC-1 - 7), well developed, size usually TC-1 = TC-4> TC-5 TC-7 (Figs. 13a, 14a, b). Ventral glandular bands and glandular areas around parapodia absent. Nephridial papillae inserted dorsally to notopodia of segments 5, 6, 7 and 8 (TC-3 - 6) (Fig. 13b). Branchiae consisting of a stout single stem dorsally between TC-1 and TC-2 (Fig. 13b). Four branchial lobes completely free from each other, bearing broad, oval-elongated lamellae that are tightly packed. Posterior lobes shorter (about 80%) and less in diameter than anterior lobes. Branchial stem annulated, filamentous tips at end of branchial lobes absent. Notopodia all comparably well developed throughout thorax, that of TC-1 smaller than subsequent ones. Notochaetae all capillaries of 2 lengths arranged in 2 tiers (Fig. 14c). Chaetal surface almost smooth, only weakly structured by upwards bent ends of chaetal thecae. First neuropodia from segment 8 (TC-6), as sessile pinnules in thorax. First neuropodium (TC-6) bearing about 2–4 acicular hooks on a slightly elevated ridge. Hooks weakly bent with fine downwards bent tips, part of hooks below bend almost completely embedded in body wall (Fig. 14d, e). No capitium apparent. Subsequent thoracic neuropodia with long-handled uncini (Fig. 14f), arranged in single rows per torus, with a stout and distinctly prolonged main fang (MF) and numerous small teeth above MF. Abdominal neuropodia and pygidium unknown. MG staining (Fig. 15a–c) corresponds with staining pattern 4 (Schüller & Hutchings 2010), with all TCs almost solidly stained. Clearly apparent white bands missing. Noto- and neuropodia bearing green colouration with fresh staining. Remarks: In comparison to all other Terebellides species found during the expedition Diva 3 this species represents a large species with a very broad and stout appearance. The anterior thorax is compact and less delicate than in the other species, and thus resembling shallow water species of Terebellides. Additional characters which they share with shallow water species of the genus are the lack of a capitium in the acicular hooks and the more or less smooth chaetal surface. Since the holotype is an ovigerous female it is, however, without doubt that the species is a real deep-sea species that also reproduces in the deep, and populations do not consist of recruits from shelf or slope environments. For comments as to how this species varies from other formerly described species in the western South Atlantic see the Discussion, but it should be noted that no other species of Terebellides have been described from such deep water in the South Atlantic to date., Published as part of Schüller, M. & Hutchings, P. A., 2012, New species of Terebellides (Polychaeta: Trichobranchidae) indicate long-distance dispersal between western South Atlantic deep-sea basins, pp. 1-31 in Zootaxa 3254 on pages 19-23, {"references":["Schuller, M. & Hutchings, P. A. (2010) New insights in the taxonomy of Trichobranchidae (Polychaeta) with description of a new Terebellides species from Australia. Zootaxa 2395, 1 - 16."]}

Terebellides atlantis Williams, 1984 Figures 2���3, 13 a Terebellides atlantis Williams 1984: 121 ���123. Holthe 1986 b: 115. Sol��s-Weiss et al. 1991: 156. Bremec and El��as 1999: 177. Hutchings and Peart 2000: 244, Table 3 a, b. Garraffoni and Lana 2003: 356. Garraffoni and Lana 2004: 973. Garraffoni et al. 2005: 8. Terebellides stroemii Hartman 1965: 227, in part; not Sars, 1835. Material examined. A total of 1684 specimens (54.15% of total) were obtained in 150 BIOICE samples. BIOICE sample 2317 (one specimen in one SEM stub IMNH 24927; 64 ��07'00''N; 09��03'00''W, 996 m), BIOICE sample 2741 (two specimens in one SEM stub IMNH 24928; 67 �� 38 ' 90 ''N; 20 �� 14 ' 28 ''W, 514 m). Occurrence. The species is present in a wide range of depths and preferably in warmer waters at both sides of the GIF Ridge. Depth range: 173���3000 m; temperature range: -0.9��C to 7.5��C. Description. Complete specimens range from 8 to 18 mm in length and 0.5 to 1.0 mm in width; body tapering posteriorly with segments increasingly shorter towards pygidium. Prostomium compact; tentacular membrane surrounding the mouth and usually devoid of buccal tentacles (Fig. 2 a). First segment forming an expanded structure below tentacular membrane. Lateral lappets on segments 3���7 (chaetigers 1���5) (Fig. 2 a). Branchiae arising as a single structure from segment 3, consisting of a single mid-dorsal stalked structure (Fig. 2 a) made up of two pairs of lobes not fused and provided with pointed projection of posterior region; posterior pair of lobes slightly shorter and thinner. Sometimes only anterior pair of lobes present; in small specimens usually only stalk persisting. No anterior projection (fifth lobe) present. Both sides of branchial lamellae provided with several concentric rows of cilia (Fig. 2 b). Eighteen pairs of notopodia (segments 3���20), compact, rectangular and of increasing size from first chaetiger backwards. Notochaetae of first three anterior chaetigers shorter and less numerous than notochaetae of subsequent notopodia (Fig. 2 a). Neuropodia present as sessile pinnules from chaetiger 6 (segment 8) to pygidium. Neuropodial uncini in single rows throughout (Fig. 2 c; 3 a). First thoracic neuropodia provided with about 5 sharply bent, acute tipped geniculate acicular hooks (Fig. 2 c���d). Upper part of geniculate chaetae provided with minute teeth forming a capitium (Fig. 2 e���f). Second and all subsequent thoracic neuropodia with up to 15 uncini per torus (Fig. 2 c; 3 a). Uncini long-shafted denticulate hooks with main fang large, surmounted by 4���5 teeth and an upper crest of numerous teeth progressively shorter (Fig. 3 b���c), dental formula: MF: 4���5:���. About 25 abdominal neuropodia as erect pinnules, with near 25 uncini per torus (Fig. 3 d���e); uncini provided with 4 teeth above main fang surmounted by 5��� 6 teeth and an upper crest of a variable number of smaller teeth (Fig. 3 f), dental formula MF: 4: 4���5:���. No nephridial papilla observed. Pygidium blunt, funnel-like depression with crenulated edge. MG staining pattern (Fig. 13 a): compact green coloration in first 13 segments, turning into a stripped pattern in segments 14���20 and fading in the following segments. Colour in alcohol pale brown. Distribution. Terebellides atlantis was only known from the type locality in the New England slope (USA) (Williams 1984; Hutchings & Peart 2000). The large number of specimens found among BIOICE material suggests that this species might have been overlooked in later studies in the North Atlantic, probably being confused with small specimens of T. stroemii. Williams (1984) reports the species in a narrow depth range (466 to 508 meters); our findings in the coast of Iceland increase this range significantly, from shallower depths (173 m) of the continental shelf to the deep slope near the bathyal boundary (3000 m). Remarks. Two of the most characteristic features of this species are its small size, much smaller than the other species found in Iceland (mature specimens were of 13 mm in length) and the presence of branchiae, consisting of 1���4 basally fused lobes provided with loosely fused lamellae. This feature has been previously reported for other Terebellides species such as T. intoshi Caullery, 1915 (Indonesia), T. lobatus Hartman and Fauchald, 1971 (New England), T. mundora Hutchings and Peart, 2000 (Australia) and T. sepultura Garraffoni and Lana, 2003 (Brazil). Terebellides intoshi differs from T. atlantis in its larger body size (50���60 mm long and 4 mm wide), number of abdominal chaetigers (35���40 vs. 25 in T. atlantis) and, following Imajima and Williams (1985) description of this species, by the presence of two chaetigers with geniculate chaetae instead of one (but see below Discussion of T. bigeniculatus sp. nov.). Terebellides lobatus differs from T. atlantis in its larger body size (up to 30 mm long and 4 mm wide), and the degree of curvature of geniculate chaetae (90 �� in T. atlantis vs. 135 �� in T. lobatus) and thoracic uncini (the front teeth of capitium are much larger than the following) (see plate 20 in Hartman & Fauchald 1971). Terebellides mundora has sharply bent geniculate chaetae such as in T. atlantis but the rostrum is much shorter and with a blunt tip (although authors qualify it as pointed). Terebellides sepultura differs in having a very large branchial stalk and a posterior pair of branchial lobes much shorter than in T. atlantis. Recently, Gagaev (2009) described T. irinae from the Canadian basin; this small-sized (6.6 to 14.6 mm long and 0.3 to 0.6 mm wide) species has also free branchial lobes. This species, characterized by Gagaev (2009) by the shorter size of the ventral pair of branchial lobes, very much resembles T. atlantis. Unfortunately, the author does not provide any comparison between the new species and T. atlantis. The study of several specimens under the SEM shows the presence of denticles on the upper part of the geniculate setae. In addition, the capitium of the thoracic uncini is endowed with teeth progressively shorter, which differs greatly from the appearance of that of the other three species of Terebellides found in Iceland (see below). The MG staining pattern observed in Icelandic specimens agrees well with pattern 1 proposed by Sch��ller and Hutchings (2010) (i.e., anterior solid, subsequently striped and fading towards posterior thorax); nevertheless, the number of anterior completely stained chaetigers (solid chaetigers) is 11 as is described in Williams (1984) (���ventral bands stain on 11 chaetigers���) and not three. The specimens from the BIOICE cruises previously identified as Terebellides cf. stroemii by Parapar and Moreira (2008 a) correspond to T. atlantis., Published as part of Parapar, Julio, Moreira, Juan & Helgason, Gudmundur V., 2011, Taxonomy and distribution of Terebellides (Polychaeta, Trichobranchidae) in Icelandic waters, with the description of a new species, pp. 1-20 in Zootaxa 2983 on pages 2-6, DOI: 10.5281/zenodo.202357, {"references":["Williams, S. J. (1984) The status of Terebellides stroemi (Polychaeta; Trichobranchidae) as a cosmopolitan species, based in a worldwide morphological survey, including description of new species. In: Hutchings, P. A. (Ed). Proceedings of the First International Polychaete Conference, Sydney, Australia, 1984. The Linnean Society of New South Wales, 118 - 142.","Holthe, T. (1986 b) Evolution, systematics, and distribution of the Polychaeta Terebellomorpha, with a catalogue of the taxa and a bibliography. Gunneria, 55, 1 - 236.","Solis-Weiss, V., Fauchald, K. & Blankesteyn, A. (1991) Trichobranchidae (Polychaeta) from shallow warm water areas in the Western Atlantic Ocean. Proceedings of the Biological Society of Washington, 104, 147 - 158.","Bremec, C. S. & Elias, R. (1999) Species of Terebellides from South Atlantic Waters off Argentina and Brazil (Polychaeta: Trichobranchidae). Ophelia, 5, 177 - 186.","Hutchings, P. & Peart, R. (2000) A revision of the Australian Trichobranchidae (Polychaeta). Invertebrate Taxonomy, 14, 225 - 272.","Garraffoni, A. R. S. & Lana, P. C. (2003) Species of Terebellides (Polychaeta, Terebellidae, Trichobranchinae) from the Brazilian coast. Iheringia, 93 (4), 355 - 363.","Garraffoni, A. R. S. & Lana, P. C. (2004) Cladistic analysis of Trichobranchinae (Polychaeta; Terebellidae). Journal of the Marine Biological Association of the United Kingdom, 84, 973 - 982.","Garraffoni, A. R. S., Lana, P. C. & Hutchings, P. (2005) A catalogue of the Trichobranchinae (Polychaeta: Terebellidae) of the world. Zootaxa, 1065, 1 - 27.","Hartman, O. (1965) Deep-water benthic polychaetous annelids off New England to Bermuda and other North Atlantic areas. Allan Hancock Foundations Publications, Occasional Paper, 28, 1 - 378.","Caullery, M. (1915) Sur les Terebellides Malmgren du Siboga et les Terebelliens voisins. Bulletin de la Societe Zoologique Francaise, 40, 111 - 116.","Hartman, O. & Fauchald, K. (1971). Deep-water benthic polychaetous annelids off New England to Bermuda and other North Atlantic areas. Part II. Allan Hancock Monographs in Marine Biology, 6, 1 - 327.","Imajima, M. & Williams, S. J. (1985) Trichobranchidae (Polychaeta) chiefly from the Sagami and Suruga Bays, collected by R / V Tansei-Maru (Cruises KT- 65 ~ 76). Bulletin of the National Science Museum, Tokyo, Ser. A, 11, 7 - 18.","Gagaev, S. Y. (2009). Terebellides irinae sp. n., a new species of Terebellides (Polychaeta: Terebellidae) from the Arctic basin. Russian Journal of Marine Biology, 35, 474 - 478.","Schuller, M. & Hutchings, P. A. (2010) New insights in the taxonomy of Trichobranchidae (Polychaeta) with the description of a new Terebellides from Australia. Zootaxa, 2395, 1 - 16.","Parapar, J. & Moreira, J. (2008 a) Redescription of Terebellides kerguelensis stat. nov. (Polychaeta: Trichobranchidae) from Antartic and subantarctic waters. Helgoland Marine Research, 62, 143 - 152."]}

Terebellides stroemii Sars, 1853 sensu Holthe (1986 a) Figures 11, 12, 13 d Terebellides stroemii Sars, 1853 396. Garraffoni et al. 2005: 14. Garraffoni and Lana 2003: 356. Garraffoni and Lana 2004: 973, Tables 1 ���2, figs. 5���6. Jirkov 2001: 529, figs. 1���5. Terebellides stroemi Williams 1984: 119, figs. 1 a���c, 3, 6. Imajima and Williams 1985: 11. Holthe 1986 a: 170. Sol��s-Weiss et al. 1981: 147. Bremec and El��as 1999: 177. Material examined. A total of 893 specimens (28.71% of total) were obtained in 185 BIOICE samples. BIOICE sample 2065 (one specimen in one SEM stub IMNH 24933; 66 �� 41 ' 88 ''N; 20 ��02' 98 ''W, 148 m). BIOICE sample 2152 (six specimens in three SEM stubs IMNH 24934 to IMNH 24936; 66 ��08' 91 ''N; 17 �� 35 ' 85 ''W, 198 m). Additional material examined. Naturhistorisk Museum, Universitetet i Oslo, C- 1528. Bundefjord (Kr.ania), 45���50 fr., 15.09. 1908 (Wollebaeck det.). Two vials with 68 and 38 specimens respectively; one vial revised by A. Wollebaek in 1908 and one by T. Holthe in 1975. Occurrence. Present in a wide range of depths and temperatures, both in cold northern and warm southern waters. Depth range: 173���1951 m; temperature range: -0.8��C to 7.2��C. Distribution. Since Williams (1984), the cosmopolitan status of T. stroemii has been questioned, and its distribution is now thought to be limited to Boreo-Arctic waters of the Atlantic Ocean (Hutchings & Peart 2000). This species was previously reported in Icelandic waters by Wesenberg-Lund (1951). Remarks. The characteristics of the Icelandic specimens correspond fairly well with the expanded redescription of specimens of T. stroemii from Norway provided by Hutchings and Peart (2000). Lateral lappets are present on segments 3���7 declining in size posteriorly and forming dorsal rounded projections on the same segments (Fig. 11 a���c). However, their development varies among the specimens, being usually larger on segments 4���6 (chaetigers 2���4) and particularly on the fifth (Fig. 11 c). These differences may be due to age or sexual maturity so this character should be used with caution in the characterization of the species. Branchiae consist of a typical mid-dorsal stalked structure made up of four lobes fused for half of their length (Fig. 11 d) and provided with numerous tightly packed flat lamellae with well defined concentric rows of cilia (Fig. 11 e). However, the Icelandic material differs from the Norwegian specimens as redescribed by Hutchings and Peart (2000) in two aspects: the position of nephridial papillae and the shape of the acicular chaetae. Thus, nephridial papillae are located in segments 6���7 (chaetigers 4���5) in BIOICE specimens (Fig. 11 b, f) instead of segments 3���4 (Hutchings & Peart 2000; fig. 16 a), and the first thoracic neuropodia of segment 8 (chaetiger 6) are sharply bent (90 ��) geniculate chaetae with pointed tip in BIOICE specimens (Fig. 12 a���b) instead of gently curved with blunt tip (Hutchings & Peart 2000; fig. 16 b). The study of specimens from Bundefjord (West Norway), identified as T. stroemii by A. Wollebaeck and T. Holthe, revealed that the arrangement of the nephridial papillae on segments 6 and 7 is consistent with that of BIOICE specimens. However, Holthe also identifies a first nephridial pore in segment 3 (chaetiger 1), which we detected neither in the Icelandic nor in the Norwegian material. This suggests that neither the material we examined nor the specimens studied by Hutchings and Peart (2000) would correspond to T. stroemii. It is very likely, according to Hutchings and Peart (2000) and contrary to what Holthe (1986 a) pointed out, that T. stroemii represents a number of closely related species. Perhaps a future revision of this taxon using other characters, such as distribution of nephridial papillae, can reveal its true diversity. Acicular chaetae from BIOICE specimens also have denticles on their apical end forming a capitium (Fig. 12 c). Thoracic uncini are characterized by a group of three large teeth over the main tooth (dental formula: MF: 3: 4) (Fig. 12 d) while the abdominal ones follow the general trend of these uncini in other species (Fig. 12 e���f). The MG staining (Fig. 13 d) results in a compact green coloration of the first 8 segments (six chaetigers), after turning into a striped pattern and fading in the posterior thoracic segments. The oval-shaped glandular region of segment 5 (chaetiger 3) is also stained., Published as part of Parapar, Julio, Moreira, Juan & Helgason, Gudmundur V., 2011, Taxonomy and distribution of Terebellides (Polychaeta, Trichobranchidae) in Icelandic waters, with the description of a new species, pp. 1-20 in Zootaxa 2983 on pages 14-17, DOI: 10.5281/zenodo.202357, {"references":["Holthe, T. (1986 a) Polychaeta Terebellomorpha. Marine Invertebrates of Scandinavia, 7, 1 - 194.","Garraffoni, A. R. S., Lana, P. C. & Hutchings, P. (2005) A catalogue of the Trichobranchinae (Polychaeta: Terebellidae) of the world. Zootaxa, 1065, 1 - 27.","Garraffoni, A. R. S. & Lana, P. C. (2003) Species of Terebellides (Polychaeta, Terebellidae, Trichobranchinae) from the Brazilian coast. Iheringia, 93 (4), 355 - 363.","Garraffoni, A. R. S. & Lana, P. C. (2004) Cladistic analysis of Trichobranchinae (Polychaeta; Terebellidae). Journal of the Marine Biological Association of the United Kingdom, 84, 973 - 982.","Jirkov, I. A. (2001) Polychaeta of the Arctic Ocean. Yanus-K: Moskva, 632 pp. [in Russian].","Williams, S. J. (1984) The status of Terebellides stroemi (Polychaeta; Trichobranchidae) as a cosmopolitan species, based in a worldwide morphological survey, including description of new species. In: Hutchings, P. A. (Ed). Proceedings of the First International Polychaete Conference, Sydney, Australia, 1984. The Linnean Society of New South Wales, 118 - 142.","Imajima, M. & Williams, S. J. (1985) Trichobranchidae (Polychaeta) chiefly from the Sagami and Suruga Bays, collected by R / V Tansei-Maru (Cruises KT- 65 ~ 76). Bulletin of the National Science Museum, Tokyo, Ser. A, 11, 7 - 18.","Bremec, C. S. & Elias, R. (1999) Species of Terebellides from South Atlantic Waters off Argentina and Brazil (Polychaeta: Trichobranchidae). Ophelia, 5, 177 - 186.","Hutchings, P. & Peart, R. (2000) A revision of the Australian Trichobranchidae (Polychaeta). Invertebrate Taxonomy, 14, 225 - 272.","Wesenberg-Lund, E. (1951) Polychaeta. The Zoology of Iceland, 2, 1 - 182."]}

Key to the North East Atlantic species of Terebellides 1. Geniculate acicular chaetae on thoracic chaetiger 6........................................................... 2 - Geniculate acicular chaetae on thoracic chaetigers 5 and 6.................................. T. bigeniculatus sp. nov. 2. Chaetigers 1 to 4 ventrally whitish................................................................. T. gracilis - Chaetigers 1 to 4 of same coloration as the following......................................................... 3 3. Branchial lobes fused; a large species (body up to 50 mm long)......................................... T. stroemii - Branchial lobes free; a small species (body less than 20 mm long)........................................ T. atlantis

Terebellides bigeniculatus sp. nov. Figures 1 b, 4−7, 13 b Material examined. A total of 181 specimens (5.66% of total) were obtained in 50 BIOICE samples. Type material. Icelandic Museum of Natural History: BIOICE sample 2591 (Holotype IMNH 24923 and six paratypes IMNH 24924; 67 º 12 ' 53 ''N; 22 º 25 ' 46 ''W; 333 m depth); BIOICE sample 2047 (five paratypes IMNH 24925; 65 º 42 '09''N; 12 º 52 ' 60 '' 272 m); BIOICE sample 2619 (three paratypes in two SEM stubs IMNH 24929 and IMNH 24930; 67 º 16 ' 86 ''N; 16 º 37 ' 77 ''W, 600 m). BIOICE sample 2868 (three paratypes IMNH 24926; 64 º 40 ' 94 ''N; 25 º 35 ' 82 ''W, 212 m). Museo Nacional de Ciencias Naturales de Madrid: BIOICE sample 2591 (26 paratypes; MNCN 16.01/ 13606) Non-type material. Icelandic Museum of Natural History: BIOICE sample 2021 (1 specimen); 2046 (3); 2047 (11); 2049 (4); 2087 (1); 2119 (3); 2124 (2); 2136 (2); 2143 (1); 2229 (1); 2241 (1); 2268 (2); 2273 (1); 2282 (1); 2303 (3); 2330 (1); 2362 (2); 2371 (2); 2427 (1); 2469 (1); 2528 (1); 2573 (4); 2583 (1); 2585 (1); 2612 (5); 2613 (16); 2618 (1); 2619 (9); 2627 (1); 2666 (3); 2673 (4); 2717 (1); 2741 (4); 2789 (1); 2887 (2); 2901 (5); 2979 (2); 2983 (1); 3023 (3); 3026 (5); 3099 (1); 3110 (1); 3247 (1); 3252 (7); 3550 (1); 3558 (1); 3588 (14). Additional material examined. Zoologisches Institut und Zoologisches Museum, Universität Hamburg. Type material of Terebellides biaciculata P– 20709. Type locality. Off North-West Iceland (333 m deep). Occurrence. Terebellides bigeniculatus sp. nov. is present at both sides of the GIF Ridge, but shows the narrowest depth range when compared to the other species, not reaching depths greater than 1000 m (Fig. 1 b). Depth range: 179-968 m; temperature range: -0.6 to 5.6ºC. Description based on holotype. Complete specimens range from 10 to 24 mm in length (22 mm in holotype) and 1.0 to 2.0 mm in width (2.0 mm in holotype) (Fig. 4); body tapering posteriorly with segments increasingly shorter and crowded towards pygidium. Prostomium compact; tentacular membrane surrounding the mouth and provided with buccal tentacles with expanded tips. First segment forming an expanded structure below tentacular membrane (Fig. 4). Lateral lappets on segments 3–7 (chaetigers 1–5) (Fig. 4, 5 a–c). Some specimens with conspicuous dorsal rounded projection in chaetigers 3 (Fig. 5 c). Branchiae arising as single structure from segment 3, consisting of a single mid-dorsal stalked structure (Fig. 4, 5 a,c) made up of two pairs of lobes fused for about one third of length; inner pair shorter. Anterior branchial projection (fifth lobe) and pointed projection of posterior region of lobes present (Fig. 5 a). Both sides of branchial lamellae provided with several concentric rows of cilia (Fig. 5 d–e). Eighteen pairs of notopodia (segments 3–20), shorter in chaetigers 1 to 6 becoming larger in subsequent chaetigers (Fig. 4, 5 f). Notopodia and notochaetae of first chaetiger similar in size to subsequent notopodia (Fig. 4, 5 a– b). Neuropodia present as sessile pinnules from chaetiger 5 (segment 7) to pygidium and provided with uncini in single rows throughout (Fig. 5 f). First and second thoracic neuropodia (chaetigers 5 and 6) with sharply bent, acute tipped, geniculate acicular hooks (Fig. 6 a–b, 7 a); 4–5 hooks in both chaetigers, numbers showing some degree of variability (Fig. 6 a–b). Upper part of geniculate chaetae provided with minute teeth forming a capitium (Fig. 7 b). Third and all subsequent thoracic neuropodia with up to 8–10 uncini per torus (Fig. 5 f). Uncini provided with longshafted denticulate hooks with main fang large and surmounted by 4 large teeth and crest of several shorter denticles (Fig. 7 c), dental formula MF: 4:∞. Twenty-two abdominal neuropodia as erect pinnules (Fig. 7 d) provided with about 20 uncini per torus (Fig. 7 e); uncini with six teeth above main fang surmounted by an upper crest of 3–4 shorter teeth and a variable number of smaller teeth (Fig. 7 f), dental formula MF: 6: 4–5:∞. Small thoracic papillae arising dorsally to thoracic notopodia (Fig. 6 c). One large nephridial papilla on each notopodium of segments 5 and 6 (chaetigers 3 and 4) with the appearance of a short, distally truncated cone (Fig. 6 d). Pygidium blunt, funnel-like depression with crenulated edge. MG staining pattern (Fig. 13 b): compact green coloration in first 11 segments, after turning into striped pattern in segments 12–14 and fading in the following segments. Colour in alcohol pale brown. Etymology. The species name refers to the presence of two thoracic neuropodia provided with geniculate chaetae. Remarks. Terebellides bigeniculatus sp. nov. differs from most Terebellides species by having two thoracic chaetigers provided with geniculate chaetae. The only currently known species sharing this feature are Terebellides intoshi Caullery, 1915, from Indonesia and Terebellides biaciculata Hartmann-Schröder, 1992, from the Rangiroa island lagoon (French Polynesia). Three paratypes of T. biaciculata were examined and the presence of geniculate setae on chaetigers 5 and 6 was confirmed. However, the presence of extremely long thoracic notochaetae in the latter (the author only illustrates the geniculate chaetae and thoracic and abdominal uncini), clearly separates it from T. bigeniculatus sp. nov. Hartmann-Schröder (1992) named this species as T. biaciculata in the text and T. biaciculatus in the figure plates; we follow Garraffoni et al. (2005) and adopt biaciculata as the species epithet. Hartmann-Schröder (1992) compares this species with Terebellides brevis Imajima and Williams, 1985 from Japan, which she considers similar in several characteristics but admitting that it has only acicular hooks on the sixth chaetiger. Caullery (1915; 1944) characterizes T. intoshi by the possession of free branchial lobes, the great size of the notopodia of the sixth thoracic chaetiger and the shape of thoracic and abdominal uncini and states the presence of geniculate chaetae in 6 th thoracic neuropodia. Later, Imajima and Williams (1985) redescribe T. intoshi from material collected in the coast of Japan and characterize the species by having special chaetae in chaetigers 6 and 7. Imajima and Williams (1985) recognize that although Caullery (1915; 1944) did not explicitly mention the presence of acicular chaetae in chaetiger 7, the specimens were identified as T. intoshi because they fit the original description according to other relevant characters. The nominal species of T. intoshi from Indonesia differs from T. bigeniculatus sp. nov. in having acicular chaetae only in chaetiger 6 and in having very large notopodia and notochaetae from chaetiger 6 and backwards. The Japanese species differs from T. bigeniculatus sp. nov. in bearing the geniculate chaetae in chaetigers 6 and 7 (segments 8 and 9) instead of 5 and 6. Caullery (1944) considers that T. intoshi resembles T. ehlersi McIntosh, 1885 from Fiji, but Imajima and Williams (1985), who examined the holotype, do not support this opinion.

Terebellides gracilis Malm, 1874 Figures 8���10, 13 c Terebellides gracilis Malm 1874: 100. Terebellides williamsae ��� Jirkov 1989: 124. Jirkov 2001: 529, figs. 1���4. Material examined. A total of 357 specimens (11.48% of total) were obtained in 95 BIOICE samples. BIOICE sample 2619 (three specimens in two SEM stubs IMNH 24931 and IMNH 24932; 67 �� 16 ' 86 ''N; 16 �� 37 ' 77 ''W, 600 m). Additional material examined. Type material of T. gracilis. G��teborgs Naturhistoriska Museum (Holotype, GNM Polych 641), H��garnssk��ren, Bohusl��n. Occurrence. Present in a wide range of depths and temperatures at both sides of Iceland. Depth range: 68 to 2076 m; temperature range: -0.6 to 7.0��C. Redescription based on holotype. Complete specimen of 32 mm in length and 2.5 mm in width in its widest part; body tapering posteriorly with segments increasingly shorter and crowded towards pygidium. Prostomium compact; tentacular membrane surrounding the mouth and provided with buccal tentacles with expanded tips. First segment forming an expanded structure below tentacular membrane (Fig. 8, 9 a). Branchiae arising as a single structure from segment 3, consisting of a single mid-dorsal stalked structure made up of two pairs of lobes of same length and fused in about one third of length; anterior projection (fifth lobe) present. Posterior region of lobes with pointed projection. Both sides of branchial lamellae provided with several tufts of cilia (Fig. 9 b���c). Lateral lappets on segments 3���7 (chaetigers 1���5) (Fig. 9 a). One large nephridial papilla on each notopodium of chaetigers 4���5 (Fig. 9 d), difficult to see in holotype, with the appearance of a buttonhole (Fig. 9 e���f). Eighteen pairs of notopodia (segments 3���20), compact, rectangular and increasing in size from first to sixth chaetiger. Thoracic neuropodia as sessile pinnules; present from chaetiger 6 (segment 8) to pygidium. Notochaetae of first chaetiger less numerous than notochaetae of subsequent notopodia. All notochaetae long capillaries. Neuropodial uncini in single rows throughout. First thoracic neuropodia started, as erect pinnules, in chaetiger 6 (segment 8), the latter slightly inflated (Fig. 9 d) and provided with 6���9 (9 in holotype) sharply bent, acute tipped, geniculate acicular hooks (Fig. 9 d, 10 a). Upper part of aciculae chaetae provided with minute teeth forming a capitium (Fig. 10 b). Second and all subsequent thoracic neuropodia with up to 16���22 uncini per torus. Thoracic uncini long-shafted denticulate hooks with main fang large and surmounted by two big teeth and a crest of five shorter denticles (Fig. 10 c); dental formula MF: 2���5:���. About 43 abdominal neuropodia with near 45 uncini per torus with 3 teeth above main fang surmounted by 5 teeth and an upper crest of a variable number of smaller teeth (Fig. 10 d), dental formula MF: 3: 5:���. Pygidium blunt, funnel-like depression with crenulated edge. Colour in alcohol pale brown; four anterior thoracic chaetigers ventrally white. MG staining pattern (Fig. 13 c): compact green coloration of first 13 segments, abruptly fading in following segments. Variation. The BIOICE specimens are usually much smaller than the type specimen (10���25 mm vs. 32 mm) and sometimes the whitish coloration of anterior segments is only evident in the fourth chaetiger or in most of the ventral part of the first three chaetigers, with the fourth one much less developed than the previous three, as was illustrated by Jirkov (1998, fig. 23.7.) for T. williamsae. Distribution. The type locality of T. gracilis is Gullmar Fjord, Koster area, Spitsbergen, Norwegian Sea, Barents Sea (74 �� 30 'N, 28 ��00'E, 385���390 m). Jirkov (1989) reports T. williamsae in the Barents and Norwegian seas (92���450 m depth) and off Iceland. Remarks. Terebellides gracilis has been considered a synonym of T. stroemii (e.g. Hartman, 1959; Holthe 1986 a; 1986 b). Nevertheless, Hansson (1998), after providing the translation of Malm���s original description of T. gracilis, showed that this species mostly differs from T. stroemii in having ventral parts of the first 4 thoracic chaetigers with white coloration. In addition, Jirkov (1989) characterised Terebellides williamsae Jirkov, 1989 against T. stroemii according to the same feature. Examination of the type specimen of T. gracilis corroborated Hansson���s suggestion and therefore we consider T. gracilis as a valid species. In addition, we did not find any significant differences between T. gracilis and T. williamsae; the latter should be regarded as senior synonym of T. williamsae. The study of several specimens under the SEM revealed a number of features not previously reported and which seem to be characteristic of T. gracilis. These are the presence of lateral lappets in chaetigers 1���5, the buttonhole shape of the nephridial pores, and the ciliature of the branchial lamellae. This ciliature is characteristically arranged in tufts instead of rows, which is the only disposition so far reported for the ciliature in the branchial lamellae of the genus Terebellides (Jouin-Toulmond & Hourdez 2006; Parapar & Moreira 2008 a; 2008 b). The geniculate chaetae are also endowed with denticles on their apical surface, the thoracic uncini have two main teeth surmounting the very large tooth (rostrum)., Published as part of Parapar, Julio, Moreira, Juan & Helgason, Gudmundur V., 2011, Taxonomy and distribution of Terebellides (Polychaeta, Trichobranchidae) in Icelandic waters, with the description of a new species, pp. 1-20 in Zootaxa 2983 on pages 11-13, DOI: 10.5281/zenodo.202357, {"references":["Malm, A. W. (1874) Annulater i hafvet utmed Sverges vestkust och omkring Goteborg. Kongelige Vetenskaps och Viterrhets Samhallets Goteborgs Handlingar, 14, 71 - 105.","Jirkov, I. A. (1989) Bottom fauna of the USSR. Polychaeta. Moscow State University Press, Moscow, 141 pp. [English translation from Russian].","Jirkov, I. A. (2001) Polychaeta of the Arctic Ocean. Yanus-K: Moskva, 632 pp. [in Russian].","Hartman, O. (1959) Catalogue of the Polychaetous Annelids of the World. Part II. Occasional Papers of the Allan Hancock Foundation, 23, 355 - 628.","Holthe, T. (1986 a) Polychaeta Terebellomorpha. Marine Invertebrates of Scandinavia, 7, 1 - 194.","Holthe, T. (1986 b) Evolution, systematics, and distribution of the Polychaeta Terebellomorpha, with a catalogue of the taxa and a bibliography. Gunneria, 55, 1 - 236.","Hansson, H. G. (1998) NEAT (North East Atlantic Taxa): South Scandinavian marine Annelida Check-List, 131 pp. Available from: http: // www. tmbl. gu. se (January 24 2011).","Jouin-Toulmond, C. & Hourdez, S. 2006. Morphology, ultrastructure and functional anatomy of the branchial organ of Terebellides stroemii (Polychaeta: Trichobranchidae) and remarks on the systematic position of the genus Terebellides. Cahiers de Biologie Marine, 47, 287 - 299.","Parapar, J. & Moreira, J. (2008 a) Redescription of Terebellides kerguelensis stat. nov. (Polychaeta: Trichobranchidae) from Antartic and subantarctic waters. Helgoland Marine Research, 62, 143 - 152.","Parapar, J. & Moreira, J. (2008 b) Revision of three species of Terebellides (Polychaeta: Trichobranchidae) described by C. Hessle in 1917 from the Southern Ocean. Journal of Natural History, 42, 1261 - 1275."]}

Terebellides jitu sp. nov. Figures 2–4 Terebellides narribri — Hutchings and Peart 2000; 247–254, in part. Material examined. Holotype. AM W 35501 (ripe male): Northern Territory, Arafura Sea, 948.46 ' S 13315.24 ' E, 158m, coll. May 2005. Paratypes. AM W 7059 (1 specimen, part on SEM stub), AM W 23828 (1 specimen): Queensland, East channel, off Tangalooma Point, Moreton Island, Queensland, Australia, 2712 ' S 15321 ' E, Dec 1972; AM W 34026 (1 specimen on SEM pins), AM W 34027 (1 specimen on SEM pins), AM W 34028 (1 specimen, gravid), AM W 34030 (1 specimen), AM W 34031 (1 specimen), AM W 34034 (1 specimen, gravid): Arafura Sea, 913.9 ' S 13329.25 ' E, 158m, coll. 21 -05- 2005 from Area C South, Australia. Additional material examined. AM W 36139 (8 specimens): New South Wales, Port Hacking, 344.6 ’ S 1516.25 ’ E, 27 Oct 1994; AM W 27473 (1 specimen, ripe male): Western Australia, 1km north east of Legendre Island, 2035.6 ’ S 11635.37 ’ E, 6 Aug 2000; AM W 27490 (1 specimen): Western Australia, between Enderby & Lewis Islands, 2035.6 ’ S 11635.37 ’ E, 28 Jul 2000; AM W 23839 (1 specimen): Western Australia, Duffield Ridge, Rottnest Island, 322.30 ’ S 11528.39 ’ E, 10 Jan 1991. Description. Holotype complete, 15 mm long and ~ 2.5 mm wide for 20 abdominal segments, mature. Additional specimens 0.3–2.9 mm long, some with coelomic gametes. Dorsum and ventrum smooth, colour yellow to reddish brown in preserved specimens. Prostomium compact, expanded tentacular membrane with numerous folds. Buccal tentacles of two kinds, uniformly tapered and with expanded tips. Remains of numerous scattered eyespots may be visible in preserved specimens dorsally on prostomium after MG staining. Peristomium consisting of hidden upper lip. And large, expanded lower lip. Second segment reduced, narrow, almost completely covered by third segment (Figs 2 a & 3 a). Lateral lappets on segments 1–6, well developed (Figs 2 a & 3 a), largest on segments three and four. Ventral glandular bands and glandular areas around parapodia absent. Nephridial papillae inserted dorsally to notopodia of segments 3, 6, and 7 (Fig. 2 a). Branchiae as single structure dorsally on segments 3 and 4, consisting of 4 distinct lobes; fused for about half their length, all of similar length (Fig. 2 b). Anterior ones broader than posterior ones, projecting anteriorly to form a seemingly 5 th lobe. Posterior lobes with distinct distal tip. All lobes composed of tightly packed lamellae, each one with transverse ridges on its surface (Fig. 2 b). FIGURE 3. Terebellides jitu sp. nov. SEM a–c AM W 34026 a—Anterior front end showing well developed lateral lappets with elevated anterior margins, b—Chaetiger 3 with 2 tiers of notochaetae, c—close up of notochaetae of chaetiger 3. d–f AM W 7059 d— 8 th thoracic neuropodia, e—lateral view of thoracic uncini from 8 th neuropodia, f—Close up of single posterior abdominal uncinus. g–h AM W 34027 g—Head on view of posterior abdominal uncini, h—More lateral view of posterior abdominal uncini. Scales: a- 100 µm, b- 20 µm, c- 2 µm, d- 10 µm, e- 10 µm, f- 2 µm, g- 2 µm, h- 2 µm Notopodia 18 pairs, starting on segment 3. First one strongly reduced, notochaetae seemingly originating from body wall but not apparently shorter than subsequent ones. Anterior notopodia shifted slightly dorsal. Chaetae arranged in 2 tiers, consisting of narrow - winged, finely pointed capillaries (Fig. 3 b) with shaft consisting of numerous compact filaments with tips slightly splayed so that surface appears plumose (Fig. 3 c). First neuropodia from segments 8 (chaetiger 6), continuing through abdomen. Thoracic neuropodia sessile pinnules with varying number of long-handled uncini (varying between 6–20 per torus, specimens observed under SEM with about 13 uncini per torus, Fig. 3 d), except first neuropodia; with ~ 6 acicular hooks, with pointed tips and sharply bent (Fig 2 c). Long - handled uncini with a dental formula of MF: 3–6: 5:~:~~. Back of uncini very striated, rows of teeth intercalated (Figs 2 d & 3 e). Abdomen length possibly depending on size of specimens, usually with more than 30 segments present. Abdominal neuropodia erect pinnules with> 15 avicular uncini (Figs 2 e–f & 3 f–h), with a dental formula of MF: 6–7: 6–8:~~:~~. Abdominal uncini with strongly crested head, covered with numerous small and scalelike teeth (Fig. 2 e, 3 f). Length of abdominal segments gradually decreasing, caudally terminating into blunt pygidium without appendages (Fig. 2 f). The staining with MG results in compact green coloration of the first 3–5 segments before turning into striped pattern (Fig. 4). Stripes are gradually fading posteriorly and vanish from about segment 12 to 15. Additionally, pronounced staining of ventro-anterior margins of segments 1–6 and thoracic noto- and neuropodia is present. Buccal tentacles with expanded tips show distinct dotted staining in contrast to the weakly stained uniformly tapering ones. Remarks. All observed material is part of the polychaete collection of the Australian Museum, Sydney, NSW, Australia. Specimens newly described as Terebellides jitu sp. nov., were originally identified as Terebellides narribri by the authors of this species (Hutchings & Peart 2000). Hutchings and Peart (2000) had already reported the presence of two variations in their material stating the occurrence of “large, white, oval, glandular patches present on chaetiger 3 as the distinguishing character. A re-examination of the material, especially after staining with MG confirmed this character for many specimens, including the holotype of T. narribri. However, all specimens with this trait were also characterized by the lack of a truly apparent reduction of the first chaetiger in contrast to the description by Hutchings and Peart (2000). Specimens without glandular patches showed reduced first notopodia, lateral lappets on segments 1–6, and also presented pronounced filamentous tips on the posterior branchial lobes. Adding up to now four distinct characters between the two variations, the species T. narribri is split up. Specimens with glandular patches on chaetiger 3, first chaetiger only slightly reduced in size compared to subsequent ones, lateral lappets on the first 5 segments, and absence of filamentous tips on posterior branchial lobes belong to Terebellides narribri. Specimens with a purely solid—striped staining pattern, strongly reduced first chaetiger, lateral lappets on segments 1–6, and pronounced tips on posterior branchial lobes are placed into the new species T. jitu sp. nov. These include two paratypes of T. narribri (AM W 7059, AM W 23828) which were collected at Moreton Bay, Queensland, the type locality of T. narribri. A differentiation based on sampling locality could not be made between the two species suggesting that the species may coexist in the same habitat. Distribution. Australian waters in shallow to moderate depths Etymology. “ Jitu is the Aboriginal (Kariyarra) word for ibis. The acicular hooks of the first neuropodia resemble the shape of the beak of the Australian white ibis (Threskiomis molucca) which is very common in Australia, especially in the area around the Australian Museum, Sydney where the material is deposited.

Terebellides jitu sp. nov. Figures 2���4 Terebellides narribri ��� Hutchings and Peart 2000; 247���254, in part. Material examined. Holotype. AM W 35501 (ripe male): Northern Territory, Arafura Sea, 948.46 ' S 13315.24 ' E, 158m, coll. May 2005. Paratypes. AM W 7059 (1 specimen, part on SEM stub), AM W 23828 (1 specimen): Queensland, East channel, off Tangalooma Point, Moreton Island, Queensland, Australia, 2712 ' S 15321 ' E, Dec 1972; AM W 34026 (1 specimen on SEM pins), AM W 34027 (1 specimen on SEM pins), AM W 34028 (1 specimen, gravid), AM W 34030 (1 specimen), AM W 34031 (1 specimen), AM W 34034 (1 specimen, gravid): Arafura Sea, 913.9 ' S 13329.25 ' E, 158m, coll. 21 -05- 2005 from Area C South, Australia. Additional material examined. AM W 36139 (8 specimens): New South Wales, Port Hacking, 344.6 ��� S 1516.25 ��� E, 27 Oct 1994; AM W 27473 (1 specimen, ripe male): Western Australia, 1km north east of Legendre Island, 2035.6 ��� S 11635.37 ��� E, 6 Aug 2000; AM W 27490 (1 specimen): Western Australia, between Enderby & Lewis Islands, 2035.6 ��� S 11635.37 ��� E, 28 Jul 2000; AM W 23839 (1 specimen): Western Australia, Duffield Ridge, Rottnest Island, 322.30 ��� S 11528.39 ��� E, 10 Jan 1991. Description. Holotype complete, 15 mm long and ~ 2.5 mm wide for 20 abdominal segments, mature. Additional specimens 0.3���2.9 mm long, some with coelomic gametes. Dorsum and ventrum smooth, colour yellow to reddish brown in preserved specimens. Prostomium compact, expanded tentacular membrane with numerous folds. Buccal tentacles of two kinds, uniformly tapered and with expanded tips. Remains of numerous scattered eyespots may be visible in preserved specimens dorsally on prostomium after MG staining. Peristomium consisting of hidden upper lip. And large, expanded lower lip. Second segment reduced, narrow, almost completely covered by third segment (Figs 2 a & 3 a). Lateral lappets on segments 1���6, well developed (Figs 2 a & 3 a), largest on segments three and four. Ventral glandular bands and glandular areas around parapodia absent. Nephridial papillae inserted dorsally to notopodia of segments 3, 6, and 7 (Fig. 2 a). Branchiae as single structure dorsally on segments 3 and 4, consisting of 4 distinct lobes; fused for about half their length, all of similar length (Fig. 2 b). Anterior ones broader than posterior ones, projecting anteriorly to form a seemingly 5 th lobe. Posterior lobes with distinct distal tip. All lobes composed of tightly packed lamellae, each one with transverse ridges on its surface (Fig. 2 b). FIGURE 3. Terebellides jitu sp. nov. SEM a���c AM W 34026 a���Anterior front end showing well developed lateral lappets with elevated anterior margins, b���Chaetiger 3 with 2 tiers of notochaetae, c���close up of notochaetae of chaetiger 3. d���f AM W 7059 d��� 8 th thoracic neuropodia, e���lateral view of thoracic uncini from 8 th neuropodia, f���Close up of single posterior abdominal uncinus. g���h AM W 34027 g���Head on view of posterior abdominal uncini, h���More lateral view of posterior abdominal uncini. Scales: a- 100 ��m, b- 20 ��m, c- 2 ��m, d- 10 ��m, e- 10 ��m, f- 2 ��m, g- 2 ��m, h- 2 ��m Notopodia 18 pairs, starting on segment 3. First one strongly reduced, notochaetae seemingly originating from body wall but not apparently shorter than subsequent ones. Anterior notopodia shifted slightly dorsal. Chaetae arranged in 2 tiers, consisting of narrow - winged, finely pointed capillaries (Fig. 3 b) with shaft consisting of numerous compact filaments with tips slightly splayed so that surface appears plumose (Fig. 3 c). First neuropodia from segments 8 (chaetiger 6), continuing through abdomen. Thoracic neuropodia sessile pinnules with varying number of long-handled uncini (varying between 6���20 per torus, specimens observed under SEM with about 13 uncini per torus, Fig. 3 d), except first neuropodia; with ~ 6 acicular hooks, with pointed tips and sharply bent (Fig 2 c). Long - handled uncini with a dental formula of MF: 3���6: 5:~:~~. Back of uncini very striated, rows of teeth intercalated (Figs 2 d & 3 e). Abdomen length possibly depending on size of specimens, usually with more than 30 segments present. Abdominal neuropodia erect pinnules with> 15 avicular uncini (Figs 2 e���f & 3 f���h), with a dental formula of MF: 6���7: 6���8:~~:~~. Abdominal uncini with strongly crested head, covered with numerous small and scalelike teeth (Fig. 2 e, 3 f). Length of abdominal segments gradually decreasing, caudally terminating into blunt pygidium without appendages (Fig. 2 f). The staining with MG results in compact green coloration of the first 3���5 segments before turning into striped pattern (Fig. 4). Stripes are gradually fading posteriorly and vanish from about segment 12 to 15. Additionally, pronounced staining of ventro-anterior margins of segments 1���6 and thoracic noto- and neuropodia is present. Buccal tentacles with expanded tips show distinct dotted staining in contrast to the weakly stained uniformly tapering ones. Remarks. All observed material is part of the polychaete collection of the Australian Museum, Sydney, NSW, Australia. Specimens newly described as Terebellides jitu sp. nov., were originally identified as Terebellides narribri by the authors of this species (Hutchings & Peart 2000). Hutchings and Peart (2000) had already reported the presence of two variations in their material stating the occurrence of ���large, white, oval, glandular patches present on chaetiger 3 as the distinguishing character. A re-examination of the material, especially after staining with MG confirmed this character for many specimens, including the holotype of T. narribri. However, all specimens with this trait were also characterized by the lack of a truly apparent reduction of the first chaetiger in contrast to the description by Hutchings and Peart (2000). Specimens without glandular patches showed reduced first notopodia, lateral lappets on segments 1���6, and also presented pronounced filamentous tips on the posterior branchial lobes. Adding up to now four distinct characters between the two variations, the species T. narribri is split up. Specimens with glandular patches on chaetiger 3, first chaetiger only slightly reduced in size compared to subsequent ones, lateral lappets on the first 5 segments, and absence of filamentous tips on posterior branchial lobes belong to Terebellides narribri. Specimens with a purely solid���striped staining pattern, strongly reduced first chaetiger, lateral lappets on segments 1���6, and pronounced tips on posterior branchial lobes are placed into the new species T. jitu sp. nov. These include two paratypes of T. narribri (AM W 7059, AM W 23828) which were collected at Moreton Bay, Queensland, the type locality of T. narribri. A differentiation based on sampling locality could not be made between the two species suggesting that the species may coexist in the same habitat. Distribution. Australian waters in shallow to moderate depths Etymology. ��� Jitu is the Aboriginal (Kariyarra) word for ibis. The acicular hooks of the first neuropodia resemble the shape of the beak of the Australian white ibis (Threskiomis molucca) which is very common in Australia, especially in the area around the Australian Museum, Sydney where the material is deposited., Published as part of Sch��ller, Myriam & Hutchings, Pat A., 2010, New insights in the taxonomy of Trichobranchidae (Polychaeta) with description of a new Terebellides species from Australia, pp. 1-16 in Zootaxa 2395 on pages 7-11, DOI: 10.5281/zenodo.193948, {"references":["Hutchings P. A. & Peart R. (2000) A revision of the Australian Trichobranchidae (Polychaeta). Invertebrate Taxonomy, 14 (2), 225 - 272."]}

Terebellides narribri Hutchings and Peart, 2000 Figures 5���7 Terebellides narribri ��� Hutchings and Peart 2000: 247 ���254, Figs 8 c���d, 11, 13c, 15 a���f, Table 3 Material examined. Holotype. AM W 5048 (1 specimen, gravid, part on SEM stub): Moreton Bay, 4 km S of SW Rocks, Peel Island, Queensland, 2730 ��� S 15321 ��� E, 1971, 5 m, sand mud and shell. Additional material examined. AM W 24057 (6 specimens, some gravid, part on SEM stub): New South Wales, Towlers Bay North, Pittwater, 3337.30 ��� S 15117 ' E, Apr 1992; AM W 24884 (30 specimens): New South Wales, Port Hacking, 344.6 ��� S 1516.25 ��� E, 27 Oct 1994; AM W 21652 (1 specimen, gravid): New South Wales, south of airport runway extension, Botany Bay, 3358.7 ��� S 15111.9 ��� E, 7 Apr 1992; AM W 23840 (2 specimens, gravid): New South Wales, Pittwater, 3333.50 ��� S 15118.43 ��� E, 20 Oct 1994; AM W 11097 (2 specimens, gravid), AM W 12243 (1 specimen): Tasmania, Huon River, 432 ' S 14617 ' E, 5 Feb 1976. Description. Holotype ovigerous female with coelomic oocytes (Figs 5 a, b), complete, 11mm long for 45 segments. Additional specimens 0.4���3.1 mm long, some gravid. Colour pale yellow to reddish brown in preserved specimens. Prostomium and tentacular membrane compact and slightly expanded. Buccal tentacles of two kinds, uniformly tapered with expanded tips. Upper lip almost completely hidden, lower lip expanded. Second segment smaller than subsequent segments, partially covered by 3 rd segment (Fig. 5 a). Lateral lappets on segments 1���5, best developed on 5 th segment (Fig. 5 a). Ventral glandular bands and glandular areas around parapodia absent. Nephridial papillae inserted dorsally to notopodia of segments 3, 6, and 7 (Fig. 5 a). Branchiae arising as single structure dorsally on segments 3 and 4, consisting of 4 distinct lobes, fused to each other for about half their length (Fig. 5 c). Anterior ones broader and longer than posterior ones. Anterior projecting (5 th lobe) present. All lobes composed of tightly packed lamellae, filamentous tips absent (Fig. 5 c). Notopodia 18 pairs, present on segments 3���20. First one well developed, only slightly smaller than subsequent ones. Chaetae arranged in 2 tiers (Fig. 6 a), narrow - winged, finely pointed capillaries. Shaft consisting of numerous compact filaments with tips slightly splayed so that surface appears plumose (Figs 6 a, b). Thoracic neuropodia starting from segment 8 (chaetiger 6), sessile pinnules. First neuropodia with ~ 5 acicular hooks with pointed tips and sharply bent shaft. Subsequent neuropodia with varying number of longhandled uncini (about 13 uncini in holotype), number often increasing from anterior to posterior. Uncini with a dental formula of MF: 3���4: 7:~:~, their head strongly crested, teeth very compact and flattened and main fang with surface striations (Figs 5 d & 6 c���e). Abdomen with more than 20 segments (25 in holotype). Abdominal neuropodia erect pinnules (Fig. 5 b) with> 30 avicular uncini (Figs 5 e & 6 f���h), with a dental formular of MF: 4���5: 6���7:~~:~~. Abdomen terminating in blunt pygidium without appendages (Fig. 5 f). FIGURE 6. Terebellides narribri a���e AM W 24057 a���Thoracic notopodia (14 th chaetiger) with 2 rows of notochaetae, b���Close up notochaetae, c���Thoracic neuropodial torus from chaetiger 14, d���Lateral view of thoracic neurochaetae, e���Head on view of thoracic neurochaetae, f���Posterior abdominal neuropodial torus, g���h���Head on view of posterior abdominal uncini. Scales: a- 20 ��m, b- 2 ��m, c- 20 ��m, d- 3 ��m, e- 3 ��m, f- 10 ��m, g- 1 ��m, h- 1 ��m The staining with MG results in a compact green coloration of the first 5 segments. The 5 th segment is characterized by large oval to ���J-shaped whitish glandular regions laterally on both sides of the segment (Fig. 7). From segment 6 on, only the anterior half of the segments is stained resulting in striped pattern which gradually fades posteriorly and vanishing by about segment 12. The ventro-anterior margins of segments 1���6 are pronounced as are the thoracic noto- and neuropodia with this staining. Remarks. The presented study detected two species among the specimens housed at the Australian Museum in Sydney previously identified as T. narribri. The clarification of characters and separation of the species T. narribri and T. jitu, resulted in additions to the original description of T. narribri by Hutchings and Peart (2000). About half the specimens observed could be designated to T. jitu, without doubt, including two original paratypes of T. narribri (AM W 7059 and AM W 23828). Treating the morphospecies of the holotype as T. narribri the species is now characterized by well developed first notopodia. Also, the white oval glandular patches in chaetiger 3 (segment 5) stated as a variation in some specimens by Hutchings and Peart (2000) become a key character of T. narribri that clearly separates it from the new species T. jitu. This required a re-assessment of all the material formerly identified as T. narribri and the separation of the new species T. jitu., Published as part of Sch��ller, Myriam & Hutchings, Pat A., 2010, New insights in the taxonomy of Trichobranchidae (Polychaeta) with description of a new Terebellides species from Australia, pp. 1-16 in Zootaxa 2395 on pages 11-14, DOI: 10.5281/zenodo.193948, {"references":["Hutchings P. A. & Peart R. (2000) A revision of the Australian Trichobranchidae (Polychaeta). Invertebrate Taxonomy, 14 (2), 225 - 272."]}

A revision of the taxonomic status of Terebellides antarcticus Hessle, 1917, Terebellides longicaudatus Hessle, 1917 and Terebellides minutus Hessle, 1917 was undertaken through the examination of the type material. Thus, T. longicaudatus is regarded as a valid species and redescribed and T. antarcticus and T. minutus are considered as junior synonyms of Terebellides kerguelensis McIntosh, 1818. Terebellides longicaudatus is characterized by the presence of large lateral lobes on chaetigers 1 to 5, 1 and 2 being the largest, first thoracic acicular neurochaetae gently bent, wide thoracic neuropodia fascicles with numerous uncini and the first notopodium greatly reduced. Comments on several body characters related to branchial and chaetal structure are also provided.

During the Spanish Antarctic expeditions “Bentart” 1994, 1995 and 2003, a number of trichobranchid (Annelida: Polychaeta) specimens were collected and identified initially as Terebellides stroemii kerguelensis McIntosh, 1885, the only known species of the genus widely recognised as valid in Antarctic waters. In the framework of a worldwide revision of the genus Terebellides, a reconsideration of the taxonomic status of this subspecies of the boreal Terebellides stroemii Sars, 1835 is done through the examination of the syntypes of T. s. kerguelensis compared with recent descriptions of the nominal species from Norwegian waters and material from Icelandic waters. Thus, T. s. kerguelensis is regarded as a valid species, T. kerguelensis stat. nov., and redescribed designating a lectotype and paralectotypes. The species is mainly characterised by the presence of an anterior branchial extension (fifth lobe), lateral lappets in five anterior thoracic chaetigers, segmental organs in chaetigers 1, 4 and 5, and first thoracic acicular neurochaetae sharply bent with pointed tips. The biological role of the segmental organs, the presence and disposition of cilia in branchial lamellae and the finding of new structures located in dorsal part of thoracic notopodia are discussed. Consejo Interinstitucional de Ciencia y Tecnología; ANT93-0996 Consejo Interinstitucional de Ciencia y Tecnología; ANT94-1161/E Ministerio de Ciencia y Tecnología; REN2001-1074/ANT Ministerio de Ciencia y Tecnología; CGL2004-01856

In a survey of the polychaetes of the Lizard Island region, six species of polychaetes belonging to the families Telothelepodidae Nogueira, Fitzhugh & Hutchings, 2013, Thelepodidae Hessle, 1917 and Trichobranchidae Malmgren, 1866 were found, from material collected during the Lizard Island Polychaete Taxonomic Workshop, and material collected by previous projects undertaken by the Australian Museum. This material includes one new species of Rhinothelepus Hutchings, 1974 (Telothelepodidae); one new species of each of the genera, Euthelepus McIntosh, 1885, Streblosoma Sars, 1872, and Thelepus Leuckart, 1849 (Thelepodidae); and one new species of Terebellides Sars, 1835 and another of Trichobranchus Malmgren, 1866 (Trichobranchidae). Keys for identification of these species are provided, together with full descriptions for all species, as well as comparisons with the morphologically most similar congeners.

Based on specimens collected during the sampling campaigns in the Northern Adriatic from 2003–2010, the diversity of genus Terebellides (Polychaeta; Trichobranchidae) was studied and three species are reported for the Northern Adriatic Sea: Terebellides gracilis Malm, 1874, Terebellides mediterranea spec. nov., and Terebellides stroemii Sars, 1835. Terebellides stroemii was the only species previously reported from the area. Terebellides gracilis is reported for the first time for the Mediterranean Sea and its geographical distribution is extended south. Terebellides mediterranea spec. nov., is characterised by the presence of long notopodia and notochaetae in the first thoracic chaetiger. These three species are compared to other Terebellides species described or reported from North Atlantic waters, and a key to Terebellides species of the North East Atlantic and Mediterranean is provided.

During taxonomic studies on the Trichobranchidae housed at the Australian Museum, Sydney morphological characters of specimens were found to serve taxonomists on four taxonomic levels – family, genus, species and specimen level. The number of neuropodial uncini per torus and abdominal segments, long considered holding information for species determination, proved to be highly variable within species. Characters found to be consistent within species were e.g., the position of nephridial papillae, shape of branchiae and chaetae, and the development of anterior segments and lateral lappets. Also, staining in methyl green resulted in a clear pattern without intraspecific variability in most cases and is since considered a helpful tool for identification of Trichobranchidae. In this study an overview of morphological characters of Trichobranchidae and their information for taxonomy is given based on the trichobranchid collection of the Australian Museum. Additionally, description of a new species Terebellides jitu sp. nov., formerly treated as a variation of Terebellides narribri, is given. The description of T. narribri is revised.

A world catalogue of the subfamily Trichobranchinae (Polychaeta: Terebellidae) is provided. Four genera and 58 species are listed, with references to original descriptions, location of types, type locality, and subsequent taxonomic and applied literature.

The family Trichobranchidae is represented inAustralian waters by ten species(Artacamella dibranchiata Knox & Cameron, 1971,A. torulosa, sp. nov.,A. tribranchiata, sp. nov.,Terebellides kowinka, sp. nov.,T. mundora, sp. nov., T. narribri,sp. nov., T. woolawa, sp.nov.,Octobranchus myunus, sp.nov.,Trichobranchus bunnabus, sp. nov.andT. gorreekis, sp. nov.) in four genera, of which ninespecies are new. Previously the ‘cosmopolitan species’Terebellides stroemii Sars, 1835 had been widelyreported from Australia; examination of material from near the type locality,Norway, revealed that the Australian material differed and represented fournew species. Terebellides stroemii does not occur inAustralian waters. Terebellides stroemii is redescribed. Additional charactersare described for the genus which may also facilitate the separation of thesespecies. A key to the genera and species present in Australia is given, aswell as tables summarising the characters of all described species in thesegenera.

The benthic communities of the Tanabe-wan on the west coast of the Kii Peninsula were surveyed quantitatively in September to October, 1937. The collection was made by means of EKMAN'S bottom sampler for the marine use, with the unit square of 1/37 sq. m., and it closes automatically as it reaches the bottom. Polychaetes dominate in the faunal constituents, making up about 71% of the total animals, and the molluscs come next by about 19% (table 2). Two distinct communities were recognized in the benthic fauna. The Maldane-association (a polychaete community) occupies the muddy bottom near the mouth of the bay, almost all stations therein deeper than 20m (fig. 1). The commonest animal to be met with on the muddy area of the inner bay is Cerithium-the Cerithium-association (a snail community), and polychaetes such as Terebellides, Magelona and Sternaspis are associated with it. The depth range of this association is 4-17m. The faunae on shallow sandy or sandy-mud stations are very poor, and so far they appear to be community fragments. It is, however, possible that by a further survey they may turn out to be fasciations of some definite associations. The population density was the greatest in the Maldane-association, but in weight the Cerithium-association exceeded others, because it contains many shells.