Terebellidae (Annelida, Terebelliformia) from Lizard Island, Great Barrier Reef, Australia Author Nogueira, João Miguel Matos Author Hutchings, Pat Author Carrerette, Orlemir text Zootaxa 2015 4019 1 484 576 journal article 10.11646/zootaxa.4019.1.18 17696c34-012b-4e06-bd03-8516d44a6814 1175-5326 289527 906BB67C-F137-4CDA-A26B-77A025725800 Loimia pseudotriloba n. sp. ( Figs 3 A–C, 51–54) Type material. Holotype : AM W.47810, MI QLD 2336, complete, 25 mm long, 3 mm wide. Paratypes : AM W.47736 (4), CReefs, LI–10–018, MI QLD 2193, Mermaid Cove (buoy), 14°38'46"S , 145°27'13"E , complete specimen, with 86 segments, 31 mm long, 3.5 mm wide, in good state of preservation; AM W.47737, CReefs, LI– 10–004, MI QLD 2185, channel bommies, 14°41'19"S , 145°27'50"E , complete specimen in 2 pieces, anterior 17 mm long, 3 mm wide, 18 mm long, 2 mm wide; AM W.44594, MI QLD 2393, mounted on SEM pin. Comparative material examined. Holotype of Loimia batilla Hutchings & Glasby, 1988 , AM W.5162. Paratypes of Loimia batilla , AM W.7097, AM W.7098; AM W.7106, AM W.7107. Non-types of Loimia ingens ( Grube, 1878 ) , NTM W.6764, NTM W.6775, NTM W.17330. Holotype of Loimia ochracea ( Grube, 1878 ) , ZMB 906, MPW 583. Holotype of Loimia triloba Hutchings & Glasby, 1988 , BMNH ZB 1986.97. FIGURE 51. Loimia pseudotriloba n. sp. AM W.47810: A–B. Entire worm, left and right lateral views, respectively; C. Thorax, ventral view; D–K. Progressively higher magnifications of the anterior end, dorsal, right lateral, ventral and left lateral views, respectively. Numbers refer to segments. Abbreviations: ll = lower lip, ul = upper lip. Scale bars: A–C = 1 mm, D–E, G, I, K = 0.5 mm, F = 0.6 mm, H, J = 0.8 mm. FIGURE 52. Loimia pseudotriloba n. sp. AM W.44594: A–E. Anterior end, dorsal, left lateral, ventral and right lateral (2) views, respectively; F. Close up of the notopodia of segments 5–9, arrows point to genital papillae; G. Transition between anterior and posterior body; H–K. Close ups of the anterior end, dorsal, ventral, right and left lateral views, respectively. Numbers refer to segments. Abbreviations: ll = lower lip, ul = upper lip. Scale bars: A, C = 700 µm, B, H = 500 µm, D = 800 µm, E = 400 µm, F, J–K = 200 µm, G = 600 µm, I = 300 µm. Description. In life, body anteriorly yellow with reddish mid-ventral shields, green after termination of notopodia, speckled with large dark spots (probably internal contents) ( Fig. 3 A–C). Transverse prostomium attached to dorsal surface of upper lip; basal part without eyespots, distal part shelf-like ( Fig. 52 A, H). Peristomium forming lips, hood-like upper lip, short, almost circular, partially covered by lobes of segment 1; short and swollen lower lip, button-like ( Figs 51 C, H–K; 52A–E, H–K). Segment 1 dorsally narrow, with pair of large lobes directed anteriorly and reaching around mid-length of upper lip; lobes almost circular, dorsal margins inserted at level of first pair of notopodia, laterally to first pair of branchiae; lobes higher laterally, at level of neuropodia, midventrally indented to partially expose lower lip. Segment 2 reduced, dorsally conspicuous, covered by lobes of segment 3 laterally and fused to it ventrally. Segment 3 with pair of elongate and distally rounded lobes, almost triangular, with narrow bases tapering to distally rounded tips, reaching beyond tips of lobes of segment 1; base with ventral edges fused to upper corners of first mid-ventral shield, at mid-length of anterior neuropodial tori, dorsal margins inserted at level of dorsal edges of neuropodia; lobes of segment 4 shorter than lobes of segment 3, rectangular, longer than wide, laterally straight and distally rounded, with distinctly narrow bases, ventral margins inserted at upper corners of second mid-ventral shield, dorsal margins at level of mid-length of anterior neuropodial tori, aligned to ventral margins of lobes of segment 3 ( Figs 51 A–K; 52A–E, H–K). Anterior segments slightly inflated dorsally. Paired dorso-lateral arborescent branchiae present on segments 2–4, dorsal to line of notopodia, with short branchial filaments branching dichotomously from secondary stems originating in a spiral from short basal stems; first pair slightly longer, about half body width at segment 2; pairs all longitudinally aligned ( Figs 51 A–B, D–G, J–K; 52A–B, D–E, H, J–K). Trapezoidal mid-ventral shields present on segments 2–15, those of segments 2–3 completely fused into single crenulated structure, following shields progressively smoother, slightly crenulate until last; blood red region on segments 12–15; first 2 shields, on segments 2–3 and 4, much wider than those of following segments, then about same width, indented posteriorly by tori, last shield almost inconspicuous ( Figs 51 A, C, H–K; 52C, I). Dorsum smooth throughout, rows of rounded tubercles absent. Notopodia beginning on segment 4, extending until segment 20; notopodia short, cylindrical to oblong, notopodia of segments 4–7 inserted progressively more laterally, then longitudinally aligned ( Figs 51 A–K; 52A–K). Narrowly-winged notochaetae in both rows throughout, those from anterior row finely serrated under SEM, chaetae of posterior row with wings at distal half ( Figs 53 E–J; 54F–H). Neuropodia present from segment 5, as low, almost sessile ridges until termination of notopodia, as elongate and thin, rectangular pinnules, from segment 21, inserted progressively more ventrally, lateral to mid-ventral groove on posterior segments ( Figs 51 A–C, F–K; 52B–E, G, I–K; 53A, D). Pectinate short-handled avicular uncini, arranged in partially intercalated to completely separate double rows, in back to back arrangement, from segment 11 until termination of notopodia, on segment 20; uncini with short base, dorsal button at mid-length of base, rounded prow, and crest with single vertical series of 5–6 progressively shorter secondary teeth throughout; main fang larger but not clearly defined, line of teeth aligned with tip of prow; under SEM, series of teeth with lateral fringe of tiny teeth ( Figs 53 K–M; 54A–E, I–L). Nephridial papillae on segments 3 and 4, between dorsal margins of lobes and bases of branchiae, genital papillae on segments 6–8, posterior to notopodia; all papillae minute ( Fig. 52 A–B, D–F, H). Pygidium with digitiform papillae ( Figs 51 A–B; 53A–C). Tube mucous, with small stones and shell fragments embedded. Remarks. The only other known Australian species of Loimia with lobes also on segment 4 are L. triloba Hutching & Glasby, 1988 and L. juani n. sp. , this latter species also found in Lizard Island and described above. These species differ from L. pseudotriloba n. sp. , however, because L. juani n. sp. has lobes of segment 1 almost reaching the tip of the upper lip and with dorsal margins inserted at the level of branchiae; lobes of segment 3 almost circular and not reaching the tips of lobes of segment 1, with dorsal margins inserted at mid-length of neuropodial tori; and lobes of segment 4 with dorsal margins reaching the level of notopodia. In contrast, in L. pseudotriloba n. sp. the lobes of segment 1 do not reach beyond mid-length of upper lip and the dorsal margins are inserted at the level of notopodia, laterally to branchiae; lobes of segment 3 are almost triangular, with narrow bases and elongate tips, reaching beyond the tips of the lobes of segment 1 and inserted dorsally at the level of the dorsal edges of neuropodia; while the dorsal margins of the lobes of segment 4 are fused to the body wall at midlength of anterior neuropodial tori. In addition, L. juani n. sp. has mid-ventral shields extending to segment 13, while in L. pseudotriloba n. sp. the mid-ventral shields extend to segment 15, and the uncini of L. juani n. sp. have distally pointed prow, with ligaments continuing downwards, while in L. pseudotriloba n. sp. , the uncinial prow is rounded. However the most striking differences between members of these species are easily seen in the different body colour patterns of live specimens (compare Fig. 3 A–C and D–F). FIGURE 53. Loimia pseudotriloba n. sp. AM W.44594: A–C. Posterior end in progressively higher magnifications, left ventrolateral, frontal and dorsal views, respectively; D. Posterior body, ventro-lateral view; E, H–J. Notochaetae of segment 17; F–G. Notochaetae of segment 5 under increasing magnifications; K–L. Uncini of segment 16 under different magnifications; M. Uncini, segment 9. Scale bars: A = 400 µm, B = 200 µm, C = 100 µm, D = 7 µm, E = 50 µm, F = 20 µm, G = 5 µm, H = 40 µm, I = 6 µm, J, M = 10 µm, K = 3 µm, L = 4 µm. FIGURE 54. Loimia pseudotriloba n. sp. AM W.44594: A. Uncini, segment 7; B–E. Posterior uncini. AM W.47810: F–G. Notochaetae of segment 5, general and chaetae from posterior row, respectively; H. Notochaetae, segment 19; I–J. Uncini under higher magnification, segment 5; K–L. Uncini, segments 19 and 26, respectively. Scale bars: A = 7 µm, B = 10 µm, C–D = 5 µm, E = 3 µm, F, H = 80 µm, G = 70 µm, I = 30 µm, J, L = 20 µm, K = 40 µm. The other Australian species with lobes on segment 4 besides L. juani n. sp. , described above, L. triloba , differs from L. pseudotriloba n. sp. because in that species prostomial eyespots are present laterally and all lobes are shorter, those of segment 1 not reaching mid-length of the upper lip; lobes of segment 3 rectangular, not reaching mid-length of lobes of segment 1 and with bases extending from the level of mid-length of the neuropodial tori to the level of notopodia (see Carrerette & Nogueira 2015). Etymology. We name this species as “ pseudotriloba ” due to the similarities with L. triloba , both species having lobes on segment 4. Type locality. Big Vicki's reef, 14°41'10"S , 145°26'32"E , Lizard Island , GBR, Australia . Distribution. Widely distributed along Lizard Island region.