Lysilla pacifica Hessle, 1917

Nogueira, João Miguel Matos, Hutchings, Pat & Carrerette, Orlemir, 2015, Polycirridae (Annelida, Terebelliformia) from Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 437-483 : 445-448

Lysilla pacifica Hessle, 1917

( Figs 4 , 5 A)

Material examined. AM W.47520, Lizard Island, Blue Lagoon, 500 m east of Palfrey Island, 14°40'S, 145°28'E, 9 Oct 1978, large corer, fine sticky sediment, 12 m, coll. Jones & Short, complete specimen, ~ 50 mm long, ~ 4 mm maximum width; AM W.47406, Lizard Island, Watsons Bay, 400 m off Chinamans Ridge, 14°40'S, 145°27'E, sand with filamentous algae, 12 m, 13 Oct 1978, complete, in good state of preservation although with some damage on thorax.

Other material examined. New South Wales: AM W.4209, Forster, Wallis Lake, boatsheds, 32°11'S, 152°30'30"E, 24 May 1968; AM W.5696, Botany Bay, Towra Point, 34°6"S, 151°9'48"E.

Description. Preserved body beige to light brown. Elongate body, distinctly swollen anteriorly, abruptly tapering to narrow, cylindrical abdomen, wider posteriorly ( Fig. 4 A–I). Prostomium at base of upper lip, both basal and distal parts developed, basal part as thick horseshoe-shaped crest, distal part with large, rounded flaring lobes and also short squared to rectangular mid-dorsal process; prostomium covering segment 1 laterally and terminating laterally to lower lip, near mouth ( Fig. 4 A–E, G–H). Most buccal tentacles missing, remaining ones of two sizes, long ones slightly expanded at tips ( Fig. 4 A–E, G–H); material from New South Wales with highly specialised long tentacles, progressively widening towards cylindrical swelling, with pointed tip. Peristomium restricted to lips, upper lip distinctly longer than wide, convoluted (upper lip torn off during manipulation of specimen AM W.47520, kept in a microvial inside original vial); lower lip short, rectangular, deeply grooved ( Fig. 4 A–E, G–H). Body anteriorly swollen, abruptly expanded on segments 3–6, then becoming less markedly expanded, progressively broader until segments 9–10, abruptly tapering from posterior part of segment 9 through segment 15, then less markedly through segment 20; posterior body swollen, abruptly tapering to pygidium; faint segmentation after termination of notopodia, with fragile body wall ( Fig. 4 A–I). Segments biannulated, segment 1 only conspicuous mid-dorsally, laterally and ventrally covered by expanded prostomium; segment 2 narrower and shorter than following segments, with relatively small, bilobed mid-ventral shield at beginning of mid-ventral groove, shield slightly longer and broader than that of segment 3, extending anteriorly until ventral edge of lower lip ( Fig. 4 A–E, G–H). Ventrum highly glandular, covered with minute papillae, arranged in poorly defined ventrolateral pads on segments 2–11; papillae slightly larger and more numerous on anterior segments; smooth body wall from segment 12, with paired longitudinal crests bordering mid-ventral groove through posterior body. Notopodia extending through 11–13 segments, until segment 13 in one specimen, 15 in the other; relatively short, cylindrical notopodia, with equal sized lobes and distally blunt tips, first pair and that of segment 14 shorter, last pair much shorter ( Fig. 4 A–H). Pinnate notochaetae in both rows ( Fig. 5 A). Nephridial and genital papillae anterior to bases of all notopodia except for last pair of specimen with 13 pairs; nephridia enlarged, rounded and swollen, with minute papillae at apex on segments 6–14 ( Fig. 4 A–H). Pygidium crenulated, with rounded ventral papilla ( Fig. 4 I).

Remarks. The most distinctive character of L. pacifica is the remarkably elongate upper lip, resembling the upper lip of some telothelepodids ( Nogueira et al. 2010, 2013). The original description of this species ( Hessle 1917) states there are 9–12 pairs of notopodia in Japanese specimens, although this is based on three poorly preserved specimens and in one of these there are 9 pairs on one side and 12 on the other. The material from Lizard Island has between 11–13 pairs of notopodia and similar variation occurs in other material from Eastern Australia. We also found that in specimens with 13 pairs of notopodia the last pair is very reduced and easily overlooked ( Fig. 3 F). Fresh material from the type locality should be re-examined to confirm the range of number of pairs of notopodia present.

Hutchings & Glasby (1986) examined the syntypes of L. pacifica , found 10–11 pairs of notopodia and concluded that the species also occurred along the east coast of Australia, although it would be useful to confirm this with molecular studies. Kupriyanova (pers comm.) has found some species of serpulids occurred both in Japan and on the east coast of Australia.

Type locality. Bonin Islands, Southern Japan.

Distribution. Pacific Ocean, from southern Japan to New South Wales, along the east coast of Australia.

Figures

FIGURE 3. Lysilla longilinea n. sp., holotype NTM W. 47407. A, D. Entire worm, dorsal and ventral views (anteriorly), respectively; B – C. Anterior end, left ventro-lateral and right dorso-lateral views, respectively; E – F. Close ups of the anterior end, right dorso-lateral and left ventro-lateral views, respectively; G. Posterior end; H. Notochaetae, segment 5. Numbers refer to segments. Abbreviations: ll = lower lip, P = basal part of prostomium, * = distal part of prostomium. Scale bars: A, D = 1 mm, B – C = 0.15 mm, E – G = 0.1 mm, H = 10 µm.

FIGURE 4. Lysilla pacifica, AM W. 47520 (superior part of upper lip accidentally torn off, joined with the rest of the body for the ventral photos). A – B. Entire worm, dorsal and ventral views (anteriorly), respectively; C – D. Thorax, left ventro-lateral and right dorso-lateral views, respectively; E. Anterior end, left ventro-lateral view; F. Close up of the termination of notopodia; G – H. Close ups of the anterior end, right dorso-lateral and left ventro-lateral views, respectively; I. Posterior end. Numbers refer to segments; unspecified arrows point to last notopodium. Abbreviations: ll = lower lip, P = basal part of prostomium, PP = prostomial process, ul = upper lip, * = distal part of prostomium. Scale bars: A – B = 1.5 mm, C = 1 mm, D = 0.6 mm, E – F, I = 0.5 mm, G = 0.4 mm, H = 0.3 mm.

FIGURE 5. Lysilla pacifica, AM W. 47520, A. Notochaetae, segment 8. Polycirrus oculeus n. sp., holotype NTM W. 23159, B – C. Progressively closer views of the notochaetae of segment 19; D. Uncini, segment 23; E – F. Uncini of two posterior neuropodia. Polycirrus rubrointestinalis n. sp., paratype AM W. 47658, G – H. Notochaetae, segments 6 and 12, respectively; I – K. Uncini, segments 6, 12 and 24, respectively. Scale bars: A – B, G = 30 µm, C, H = 20 µm, D – F = 5 µm, I – K = 6 µm.