Loimia tuberculata, Nogueira, João Miguel Matos, Hutchings, Pat & Carrerette, Orlemir, 2015

Nogueira, João Miguel Matos, Hutchings, Pat & Carrerette, Orlemir, 2015, Terebellidae (Annelida, Terebelliformia) from Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 484-576 : 548-554

Loimia tuberculata n. sp.

( Figs 2 J–L, 41–44)

Type material. Holotype: AM W.44280, MI QLD 2359, 30 mm long, 3 mm wide, complete. Paratypes: AM W.44285, MI QLD 2371, mounted on 2 SEM pins; AM W.47724, CReefs, LI–10–022, MI QLD 2196, Watson’s Bay, 14°38'45.7"S, 145°27'13"E, in Halimeda , complete, 57 segments, regenerating last 9, 38 mm long, 3 mm wide, in relatively good state of preservation; AM W.47725, CReefs, LI–10–028, MI QLD 2197, MacGillivray Reef, deep reef slope, 14°39'24"S, 145°29'34"E, incomplete specimen, with 43 segments; AM W.47726 (3), CReefs, LI–10–87, High Rock, 14°49'25.0"S, 145°33'9.4"E, one specimen complete (but with posterior part of abdomen almost broken), with 83 segments plus at least 5 regenerating, 50 mm long, 5 mm wide at posterior thorax, other specimens incomplete, one of which large, with 36 segments, the other much shorter, with 30 segments.

Other material examined. AM W.44524, MI QLD 2387; AM W.47727, CReefs, LI–10–004, MI QLD 2185, Lizard Island, channel bommies, 14°41'19"S, 145°27'50"E; AM W.47731, Creefs, LI–10–018, MI QLD 2193, Mermaid Cove (buoy), 14°38'46"S, 145°27'13"E; AM W.47732, CReefs, LI–10–009, MI QLD 2188, North Direction Island, 14°44'43"S, 145°30'18"E; AM W.47821, Creefs, LI–10–109, MI QLD 2227, Bommie Bay, 14°39'35"S, 145°28'16"E.

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.

Description. In life, body anteriorly pale to reddish, with dark stripes at intersegmental grooves and discontinuous bands of dark pigmentation, body greenish after mid-body, with rings of white tubercles; mid-ventral shields terminating with blood red region; colourless buccal tentacles with pairs of pink spots all along their length ( Fig. 2 J–L); after preservation, some specimens with relatively well preserved pigmentation, fading over time. Transverse prostomium attached to dorsal surface of upper lip; basal part without eyespots; distal part shelf-like ( Figs 41 G, K–L; 42B–D, G). Peristomium forming lips, hood-like upper lip, short, almost circular, almost completely hidden by lobes of segment 1; short and swollen lower lip, button-like ( Figs 41 C–D, I; 42B–D, G). Segment 1 dorsally narrow, with pair of large lobes directed anteriorly and reaching slightly beyond mid-length of upper lip; lobes rounded, almost circular, dorsal margins inserted laterally to first pair of branchiae; lobes higher ventro-laterally at level of neuropodia, mid-ventrally indented to partially expose lower lip. Segment 2 reduced, dorsally conspicuous, covered by lobes of segment 3 laterally and partially fused to it mid-ventrally. Segment 3 with pair of large lobes, almost rectangular, rounded at corners, reaching slightly beyond base of lobes of segment 1; lobes bases narrower than tips, ventral edges fused to mid-ventral shield, dorsal margins not reaching dorsal edges of neuropodia, tips extending dorsally in relation to base, reaching bases of branchiae; lobes of segment 4 absent ( Figs 41 A–L; 42A–G). Anterior segments not 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, branchiae of second pair inserted slightly laterally to other pairs ( Figs 41 A–B, E–H, J–L; 42B–D, G–I). Mid-ventral shields present on segments 2–15, last shield almost inconspicuous, those of segments 2–4 almost completely fused into single crenulated structure, following shields progressively smoother; dark spot corresponding to blood red region on segments 12–15; anterior shields rectangular, then trapezoidal, indented posteriorly by tori ( Figs 41 B–D, I; 42A, D–F). From segment 5 to posterior body, each segment with row of irregularly sized rounded tubercles dorsally, aligned with parapodia ( Figs 41 A–B, E–H, J–K; 42B–D, G, K; 44M). Notopodia beginning on segment 4, extending until segment 20; notopodia short, rectangular, first pair slightly shorter, notopodia of segments 4–7 inserted progressively more laterally, then longitudinally aligned ( Figs 41 A–K; 42A–G, J–K; 44A–B). Narrowlywinged notochaetae in both rows throughout, those from posterior row with wings at distal half ( Figs 43 A–D; 44A–E). Neuropodia present from segment 5, as low, almost sessile ridges until termination of notopodia, as elongate and thin, rectangular pinnules, from segment 21 ( Figs 41 A–F, H–J; 42A, C–G, J–K). Pectinate, shorthandled 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, almost inconspicuous dorsal button at mid-length of base, and crest with single vertical series of 7 progressively shorter secondary teeth, on anterior segments, 6 teeth from segment 11 onwards; main fang larger but not clearly defined, line of teeth aligned with tip of prow; under SEM, series of teeth with lateral fringe of minute teeth ( Fig. 43 E–K; 44F–L). Nephridial papillae on segment 3, between dorsal margins of lobes and bases of branchiae, genital papillae on segments 6–8, posterior to notopodia; all papillae minute ( Fig. 41 E–F, H, J; 42C–D). Pygidium slightly crenulate. Tube mucous, with small stones and shell fragments embedded.

Remarks. Loimia tuberculata n. sp. differs from all previously known Australian species of Loimia in possessing a dorsal ring of round tubercles per segment from segment 5 until the last segments. The only other species with similar tubercles is L. keablei n. sp. described below, but members of that species only have tubercles after the termination of notopodia (see below).

Loimia tuberculata n. sp. has very large and circular lobes on segments 1 and 3, which clearly distinguishes it from L. batilla Hutchings & Glasby, 1988 , only known from Moreton Bay, in southern QLD. In addition, the lobes of segment 3 are larger and oblique in L. batilla , connected to each other by low collar across the ventrum, instead of rectangular, rounded at corners, and completely separated as in L. tuberculata n. sp.

We examined the types of L. ochracea ( Grube, 1878) , described from Mermaid Cove, WA, and found that they are not in good condition, lacking all branchiae, while buccal tentacles and all notochaetae are damaged. The types of L. ochracea lack lobes on segment 1, segment 2 has small rounded ventro-lateral lobes connected mid-ventrally, and segment 3 has small semi-spherical lobes directed dorso-laterally. This arrangement of lobes differs from Loimia tuberculata n. sp.

Another species, L. ingens ( Grube, 1878) , was recorded from several locations on the GBR by Hutchings & Glasby (1988), but the authors were unable to examine any material from the type locality, the Philippines, and we suspect this was wrongly identified. Hutchings & Glasby (1988) suggested that species may represent a complex of species, as they noticed considerable variation in several characters which we regard as important. Therefore all their material should be rechecked and it may be that some of these new species from Lizard Island occur elsewhere in tropical Australia. Loimia ingens also has the lobes of segment 3 fused to each other by low collar across the ventrum, but this is not found in L. tuberculata n. sp. or any of the other new species from Lizard Island described in this paper.

Etymology. We name this species after the characteristic ring of tubercles, present at level of parapodia of each segment, beginning from segment 5.

Type locality. South east of Lizard Island, 14o44'35.6"S, 145o30'20.4"E, reef on north west side of North Direction Island, GBR, Australia.

Distribution. Widely distributed along Lizard Island region.

Figures

FIGURE 2. Live specimens. A – B. Pista kristiani n. sp. AM W. 45451, MI QLD 2445; C – D. Lanicides rubra n. sp. AM W. 44272, MI QLD 2344; E – G. Eupolymnia chlorobranchiata n. sp. AM W. 45455, MI QLD 2446; H – I. Pistella franciscana n. sp. H. Discarded specimen; I. AM W. 44593, MI QLD 2394; J – L. Loimia tuberculata n. sp; J – K. Spec. AM W. 44280, MI QLD 2359; L. Discarded specimen. Photos: A – K—Alexander Semenov, L—Gary Cranitch.

FIGURE 41. Loimia tuberculata n. sp. AM W. 44280: A – B. Entire incomplete worm, left and right lateral views; C – G. Anterior end, ventral (2), left and right lateral, and dorsal views, respectively; H – L. Close ups of the anterior end, left lateral, ventral, right lateral and dorsal (2) views, respectively. Numbers refer to segments; P = basal part of prostomium; ul = upper lip; * = distal part of prostomium. Scale bars: A – B = 1.5 mm; C – E = 0.8 mm; F, I, K = 0.6 mm; G = 1 mm; H, J = 0.5 mm; L = 0.3 mm.

FIGURE 43. Loimia tuberculata n. sp. AM W. 44285: A – D. Closer views of the notochaetae of segments 5 and 18, respectively; E, G. Uncini from the segment 5 under different magnifications; F, H. Closer views of the uncini from the segment 18, under different magnifications; I – J. Uncini, segment 23, under different magnifications; K. Posterior uncini, segment 73. Scale bars: A = 100 µm, B = 70 µm, C = 80 µm, D = 50 µm, E – F, J – K = 30 µm, G – I = 20 µm.