Terebella leslieae, Santos & Nogueira & Fukuda & Christoffersen, 2010

Santos, Andre Souza Dos, Nogueira, João Miguel De Matos, Fukuda, Marcelo Veronesi & Christoffersen, Martin Lindsey, 2010, New terebellids (Polychaeta: Terebellidae) from northeastern Brazil, Zootaxa 2389 (1), pp. 1-46 : 16-24

Terebella leslieae sp. nov.

( Figs 6–10 ; Table 2)

Material examined. Type series. Holotype and paratypes 1–7 coll. Sta. 20 (05°04’46.9”S 36°26’19.5”W), 8 Nov 2007; holotype MZUSP 01042; paratype 1 MZUSP 01043, paratype 2 CIPY-POLY-1388, paratype 3 CIPY-POLY-1389, paratype 4 CIPY-POLY-1390, paratypes 5-6 LACM-AHF POLY 2256, paratype 7 ZMUC- POL-2106. Paratypes 8–10 coll. Sta. 22 (05°05’12.9”S 36°28’03.8”W), 10 Nov 2007; paratype 8 CIPY-POLY 1391, paratype 9 ZMUC-POL-2107, paratype 10 MZUSP 01044. For more information on each specimen of type-series see Table 2.

Additional material. Sta. 6 (05°04’57.9”S 36°28’31.5”W): 1 spec., coll. 10 Nov 2007. Sta. 20 (05°04’46.9”S 36°26’19.5”W): 8 specs plus 2 posterior ends and pieces of tubes, coll. 8 Nov 2007. Sta. 22 (05°05’12.9”S 36°28’03.8”W): 2 specs, coll. 10 Nov 2007.

Comparative material examined. Terebella turgidula Ehlers, 1887 . Holotype ( MCZ 846 ), coll. Expedition Blake, USA, Florida, Key West, by A. Agassiz, 2–4 m, 1877–1878; incomplete spec., in poor state of preservation, damaged, almost broken in two pieces at midlength of region with biramous parapodia and also at transition between region with biramous parapodia and region after notopodia terminate; slides: notochaetae from segment 18; neurochaetae from segments 7, 12, 23 and 61.

Terebella cf. verrilli ( Verrill, 1873) sensu Nogueira, 2008 . Non-type specs ( YPM 30168), coll. Systematics Ecology Program 251, USA, Massachusetts, Woods Hole Harbor, Vineyard Sound, 15 Feb 1960, 2 incomplete specs in good state of preservation; non-type spec. ( YPM 40571): coll. Systematics Ecology Program 251, USA, Massachusetts, Woods Hole Harbor, Vineyard Sound, 15 Feb 1960, complete spec. in good state of preservation; slides: notochaetae from segments 7, 15, 31 and 56; neurochaetae from segments 7, 10, 11, 26 and +80.

Description. Thick tube, mucous, with sand, small stones and fragments of shells embedded ( Fig. 6A ). Complete specimens 11–32 (32) mm long, 0.8–1.8 (1.7) mm wide, buccal tentacles 7–16 (16) mm long, complete specimens with 53–80 (74) segments ( Table 2). Preserved body uniformly beige, without distinct patterns of pigmentation ( Fig. 6A–L ); body progressively wider until segment 10–11; anterior segments compact, about same length until segment 13, then segments longer ( Figs 6B–G, I–K ; 7A–G, J–L ). Ventral shields on segments 2–13 or 14 (14), smooth shields, trapezoidal, slightly progressively wider until segment 7, then progressively narrower and longer until last 2–3 shields, which are distinctly narrower and shorter ( Figs 6C–E, I–K ; 7B, E–F ); after segments 13–14, shields substituted by mid-ventral groove extending until pygidium ( Figs 6D, H ; 7A–B, E–F, H–I ). Prostomium at base of upper lip; distal part forming laterally higher shelf-like process, from which buccal tentacles originate ( Figs 6C–G, I–K ; 7A–G, J–L ); basal part of prostomium with thin row of eyespots more concentrated laterally, usually leaving mid-dorsal gap. Peristomium restricted to lips; upper lip longer than wide; lower lip swollen, cushion-like ( Figs 6C–E, I–K ; 7A–G, J–L ). Segment 1 dorsally conspicuous, narrow, ending ventro-laterally below expanded lower lip or partially fused to it ( Figs 6C–G, I–K ; 7A–G, J–L ), distinction between lower lip and segment 1 unclear and strongly dependent on state of preservation of specimens. Anterior segments not markedly inflated dorsally ( Figs 6A–C, E–G, I, K ; 7A, C–D, G, J–L ). Three pairs of branching branchiae on segments 2–4, with conspicuous basal stem and short distal filaments; first pair slightly longer, second pair shorter, third pair almost same size as first; second pair lateralmost, vertically aligned with notopodia from segment 4, third pair dorsalmost, well separated from notopodia of segment 4 ( Figs 6C, E–G, I, K ; 7C–D, G, J–L ). Notopodia from segment 4, extending until segment 27–36 (29 on left side of body, 30 on right side) ( Table 2); notopodia short, rectangular, white glandular tissues not clearly visible; first pair same size as following ones, slightly dorsally aligned to them ( Figs 6C, E–G, I, K ; 7A–B, D, F–G, J–L ); last 2–3 pairs markedly shorter. Notochaetae on both tiers medially narrowly-winged, with serrated blade throughout, those on anterior tier with blade basally at an angle of about 90 o with the shaft and curled tip, chaetae on posterior tier at least twice as long as those on anterior tier, with wing starting from point at which chaetae emerge from body wall and terminating at base of blade, and almost straight blade, aligned with shaft ( Figs 8A–D ; 9A–I ). Neuropodia beginning from segment 5, as low rectangular ridges slightly raised from surface of body throughout ( Figs 6A–L ; 7A–B, D–L ), situated laterally to mid-ventral groove from segment on which ventral shields terminate ( Figs 6D, H, L ; 7A–B, E–F, H–I ), internal neuropodial shafts and neuropodial dorsal papilla both absent. Uncini short-handled throughout, with short triangular heel, short prow, downwardly directed process present, large dorsal button, situated at mid-length between base of main fang and tip of prow, not forming tuft of bristles below main fang, and crest with 2–3 rows of secondary teeth ( Figs 8E–F ; 10A–I ); uncini arranged in double rows until close to pygidium (holotype with uncini arranged in double rows until 9 segments before pygidium); double rows in an intercalated, with a partially back-to-back arrangement from segment 11 until posterior segments ( Figs 8F–G ; 10C–I ). Nephridial papillae as one pair of large, cylindrical papillae on segment 3, situated anteriorly, slightly dorsally to base of branchiae on segment 3 and vertically aligned to base of branchiae on segment 2 ( Figs 6F–G ; 7F–G, K–L ); genital papillae between parapodial lobes on segments 6–7 ( Fig. 7D, G, J–L ). Pygidium smooth ( Figs 6L ; 7A–B, H–I ).

Remarks. Terebella leslieae sp. nov., is smaller than most species of Terebella and, in addition, has some characters which are not found in most other species of the genus. Most species of Terebella have the same type of notochaetae on anterior and posterior tiers within the same notopodium, frequently with a transition on the type of notochaetae present from anterior to midbody notopodia, notopodia extending for a large number of segments, frequently until close to pygidium, double rows of uncini completely separated from each other, in a beak-to-beak arrangement, and more pairs of genital papillae, beginning from segment 6.

In T. leslieae sp. nov., however, the notochaeta of the anterior row and the posterior row within the same notopodium are different throughout, and the uncini are arranged in a partial back-to back position. This latter character is difficult to see with light microscopy as when parts of the tori are compressed by cover slips they are often forced into a lateral position which distorts the arrangement of the uncinial rows ( Fig. 8F ). They are best observed in frontal view without compression ( Fig. 8G ). Viewed under the SEM the rows also seem to be completely intercalated, as the beaks of the uncini of one row terminate at the same level as the posterior crest of the uncini of the other row. Although they appear to be completely intercalated, the outward pointing position of the prows (as seen by the protuberances in the integument) show that the uncini of the two rows are really in a partial back-to-back arrangement ( Fig. 10C–I ).

The arrangement of the double rows of uncini is not usually mentioned in most taxonomic descriptions, but at least two Australian species of Terebella , T. pappus and T. tantabiddycreekensis , have uncini in a partial back-to-back arrangement on posterior segments (Nogueira et al. in press). Both these species differ from T. leslieae sp. nov., in having ventral shields extending to segment 16, notopodia extending until close to pygidium, with a single type of notochaetae throughout, medially narrowly-winged, with serrated blade along the same axis as the shaft, and genital papillae on segments 6–9. In contrast, T. leslieae sp. nov., has ventral shields until segment 13–14, two types of notochaetae throughout, both medially winged with serrated blade, but those on anterior tier with the blade basally at an angle of about 90 o with the shaft, while those on posterior tier have the blade aligned with the shaft, and genital papillae present only on segments 6–7.

As said above, a single species of Terebella has been previously reported for the Brazilian coast, T. pterochaeta Schmarda, 1861 , which was identified from the State of São Paulo ( Amaral et al. 2006). However, these records ( Morgado 1980; Duarte & Nalesso 1996) are from ecological studies, no descriptions of the Brazilian specimens were provided and the specimens are not available for study, because they were not deposited in any museum or collection. According to the redescription provided by Day (1967) from material from South Africa, which is the type-locality of T. pterochaeta , this species differs from T. leslieae sp. nov., in being a larger species, reaching up to 100 mm, and in having 2 pairs of branchiae (although the original description states that 3 pairs of branchiae are present [ Schmarda 1861; see Hutchings & Glasby 1988]), notochaetae with broader medial wing, especially on anterior notopodia, and uncini with 3–4 rows of secondary teeth, while the longest specimen of T. leslieae sp. nov., examined for the present study is 32 mm long and the species has 3 pairs of branchiae, notochaetae throughout with narrow medial wing basally to the serrated blade and uncini with 3 rows of secondary teeth. In addition, Day (1967) did not mention the arrangement of the double rows of uncini, or the segments on which genital papillae are present, but, according to his Fig. 36.10A, the latter are present between parapodial lobes of segments 5–22.

For the Caribbean region, in addition to T. pterochaeta , a single species of Terebella has been reported, T. verrilli ( Verrill, 1873) . Terebella turgidula Ehlers, 1887 was also described from this region, but it was synonymized to Eupolymnia crassicornis ( Schmarda, 1861) by Augener (1925) and that was considered as correct by Hartman (1938), Rullier (1974) and Holthe (1986). However, Londoño-Mesa (2009) considered that the synonymy was incorrect and that this taxon actually belongs to Terebella . We have examined the holotype of T. turgidula and, as stated in the original description ( Ehlers 1887), it has lobes on anterior segments and notopodia extending until segment 18, with distally winged notochaetae. In addition, it has neuropodia of the region after notopodia terminate as raised pinnules bearing uncini arranged in a single row. All these characters match the diagnosis of Eupolymnia , but not that of Terebella . A formal redescription of this taxon will be provided soon (Nogueira et al. in prep.).

A redescription of T. verrilli was recently provided by Nogueira (2008), as T. cf. verrilli , based on material from the type-locality, in Massachusetts, USA. According to Nogueira (2008), T. verrilli differs from T. leslieae sp. nov., in being a larger species, reaching around 60 mm in length, and in having ventral shields on segments 2–12, the anterior ones crenulated, notopodia extending until posterior body, with notochaetae on anterior notopodia with basally swollen medial wing, without wing on notochaetae of posterior notopodia, double rows of uncini completely separated from each other, in a beak-to-beak arrangement, and genital papillae on segments 6–10, while T. leslieae sp. nov., in addition to what has been said above, has all ventral shields smooth, and notopodia extending until segments 27–36, followed by long region with neuropodia only.

Etymology. We dedicate this species to Leslie Harris, collection manager of the polychaete collection of the Los Angeles County Museum of Natural History (LACMNH), not only for her friendship with one of us (JMMN), but also as a deserved homage to a person who has always provided access to the polychaete collection of the LACMNH for polychaetologists from the whole world, giving support much beyond that expected from her and frequently hosting them in her own home.

Figures

FIGURE 6. Terebella leslieae sp. nov. A: worm inside tube, left ventro-lateral view; B: entire worm; C: anterior end, left lateral view; D: anterior end, ventral view; E: anterior end, right lateral view; F–G: anterior end, dorsal view; arrows point to nephridial papillae; H: posterior segments, right ventro-lateral view; I: detail of anterior end, right lateral view; J: detail of anterior end, ventral view; K: detail of anterior end, left lateral view; L: posterior end, left ventro-lateral view. A from paratype 1 (MZUSP 01043); B–L from holotype (MZUSP 01042). Numbers refer to segments; ll = lower lip; P = prostomium; ul = upper lip. Scale bars: A = 1 mm; B = 2 mm; C–E, I, K = 0.5 mm; F = 0.8 mm; G–H, J, L = 0.4 mm.

FIGURE 7. Terebella leslieae sp. nov. Paratype 10 (MZUSP 01044). A–B: total worm; C: anterior end, dorsal view; D: anterior end, right lateral view; E: anterior end, ventral view; F: anterior end, left ventro-lateral view; G: anterior end, left lateral view; H: posterior end, ventral view; I: posterior end, left ventro-lateral view; J: detail of anterior end, right lateral view; K–L: details of anterior end, left lateral view. Numbers refer to segments; arrows point to nephridial and genital papillae; ll = lower lip; P = prostomium; ul = upper lip. Scale bars: A–B = 0.6 mm; C = 0.4 mm; D–G, J = 0.3 mm; H–I, L = 0.1 mm; K = 0.2 mm.

FIGURE 8. Terebella leslieae sp. nov. Holotype (MZUSP 01042). A: notochaetae, segment 5; B: notochaetae, segment 15; C: notochaetae from posterior tier, segment 5; D: notochaetae from anterior tier, segment 5; E: uncini, segment 6; F: uncini segment 33; G: uncini, segment 47, from entire holotype temporarily mounted in a drop of ethanol. Scale bars: A– B = 50 µm; C = 30 µm; D = 20 µm; E = 15 µm; F–G = 10 µm.

FIGURE 9. Terebella leslieae sp. nov. Paratype 10 (MZUSP 01044). A-B: notochaetae segment 5, from left and right sides of the body, respectively; C: notochaetae, segment 6; D: notochaetae, segment 11; E: notochaeta from anterior tier, segment 5; F: notochaeta from anterior tier, segment 18; G: blade of one notochaeta from posterior tier, segment 8; H: blades of two notochaetae from posterior tier, segment 18; I: transition between winged shaft and blade of one notochaeta from posterior tier, posterior notopodium. Scale bars: A = 30 µm; B–D = 20 µm; E = 9 µm; F = 10 µm; G = 6.9 µm; H = 12 µm; I = 4.8 µm.

FIGURE 10. Terebella leslieae sp. nov. Paratype 10 (MZUSP 01044). A: uncini, segment 8; B: uncini, segment 8; C: uncini, segment 11; D: uncini, segment 11; E–F: uncini, segment 12; G: uncini from region after notopodia terminate; H: uncini, segment 18; I: uncini from region after notopodia terminate. Scale bars: A, I = 6 µm; B = 3 µm; C, E = 8 µm; D = 5.6 µm; F–G = 4.5 µm; H = 5 µm.