Anguillosyllis enneapoda, Maciolek, 2020

Maciolek, Nancy J., 2020, Anguillosyllis (Annelida: Syllidae) from multiple deep-water locations in the northern and southern hemispheres, Zootaxa 4793 (1), pp. 1-73 : 56-59

Anguillosyllis enneapoda n. sp.

Figures 27–28

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Material examined. (40specimens from27stations) South China Sea,off Brunei. Coll.J.A.Blake: Sta. 12, 6Jun2011, 5°49′20.73816″N, 114°09′45.51185″E, 1469 m, 1 specimen ( MCZ 147963 ) ; Sta. 15, 6 Jun 2011, 5°44′32.59263″N, 114°04′34.13854″E, 1721 m, 2 specimens ( MCZ147964 ) ; Sta. 16, 5 Jun2011, 5°43′02.93420″N, 114°04′33.77977″E, 1649 m, 2 specimens ( MCZ147965 ) ; Sta. 20, 5Jun 2011, 5°48′57.17939″N, 114°10′54.28492″E, 1435 m, 2specimens ( MCZ 147966 ) ; Sta. 25, 5 Jun 2011, 5°47′23.69441″N, 114°10′48.45326″E, 1402 m, 1 specimen ( MCZ 147967 ) ; Sta. 29, 4 Jun 2011, 5°43′01.15997″N, 114°06′07.18190″E, 1537 m, 1 specimen ( MCZ 147968 ) ; Sta. 32, 4 Jun 2011, 5°44′28.60071″N, 114°09′16.86792″E, 1415 m, 2 specimens ( MCZ 147969 ) ; Sta. 35, 3 Jun 2011, 5°47′37.12906″N, 114°14′10.75153″E, 1329 m, 1 specimen ( MCZ 148500 ) ; Sta. 47, 2 Jun 2011, 5°47′21.86444″N, 114°17′10.72194″E, 1242 m, 1 specimen ( MCZ 148501 ) ; Sta. WH_Jokit-SW, 5 Jun 2011, 5°46′27.76503″N, 114°07′33.98027″E, 1487 m, 1 specimen ( MCZ 148502 ) . Coll. P. Neubert: Sta. AN2, 27 Jun 2011, 5°25′43.52552″N, 113°47′34.41444″E, 1568 m, 1 specimen ( MCZ 148503 ) ; Sta. AN3, 28 Jun 2011, 5°28′16.43794″N, 113°49′34.34518″E, 1540 m, 1 specimen ( MCZ 148504 ) ; Sta. AN5, 27 Jun 2011, 5°26′51.39448″N, 113°46′41.57612″E, 1632 m, holotype ( MCZ 148506 ) , 6 paratypes ( MCZ 148505 ) ; Sta. AN8, 27 Jun 2011, 5°27′56.15653″N, 113°45′42.93641″E, 1783 m, 2 specimens ( MCZ 148507 ) ; Sta. AN9, 28 Jun 2011, 5°30′30.14745″N, 113°47′38.56098″E, 1820 m, 1 specimen ( MCZ 148508 ) ; Sta. DA3, 3 Jul 2011, 5°25′15.03011″N, 113°29′30.52872″E, 1772 m, 1 specimen ( MCZ 148509 ) ; Sta. JA1, 30 Jun 2011, 5°28′22.57522″N, 113°36′38.54386″E, 1888 m, 2 specimens ( MCZ 148510 ) ; Sta. JA4, 30 Jun 2011, 5°30′54.36931″N, 113°37′21.11932″E, 1967 m, 1 specimen ( MCZ 148511 ) ; Sta. JA6, 30 Jun 2011, 5°31′02.11247″N, 113°36′27.60639″E, 1999 m, 1 specimen ( MCZ 148512 ) ; Sta. ME14, 26 Jun 2011, 5°25′20.73778″N, 113°39′02.48164″E, 1792 m, 1 specimen ( MCZ 148513 ) ; Sta. ME16, 26 Jun 2011, 5°24′24.44585″N, 113°35′28.03023″E, 1805 m, 2 specimens ( MCZ148514 ) ; Sta. SA3, 3 Jul 2011, 5°35′09.05425″N, 113°38′49.25754″E, 2117 m, 1 specimen (NJM); Sta. SE1, 28 Jun 2011, 5°33′07.24983″N, 113°46′11.03389″E, 1894 m, 1 specimen ( MCZ 148515 ) ; Sta. SE5, 28 Jun 2011, 5°35′44.35485″N, 113°47′09.29726″E, 1947 m, 1 spec- imen ( MCZ 148516 ) ; Sta. SE6, 28 Jun 2011, 5°35′12.78573″N, 113°44′06.06326″E, 2095 m, 1 specimen ( MCZ 148517 ) ; Sta. TA5, 2 Jul 2011, 5°27′50.62360″N, 113°26′34.31837″E, 2008 m, 1 specimen ( MCZ 148518 ) ; Sta. TU4, 25 Jun 2011, 5°12′34.01837″N, 113°42′17.60077″E, 1439 m, 1 specimen ( MCZ 148519 ) .

Description. Body with 9 setigers, colorless, more-or-less linear in shape ( Figs. 27A , 28 A–B); most specimens including holotype 1.0 mm long without anal cirri, 0.2 mm wide without parapodia, 0.5–0.6 mm wide with parapodia but excluding setae. Palps completely fused, narrowing to slightly rounded anterior tip, without medial notch ( Figs. 27A , 28 A–B); eyes lacking; prostomium oval with anterior border slightly dome-shaped, three club-shaped antennae in transverse row; peristomium well-defined, nearly as long as prostomium, with two small, oval tentacular cirri. Nuchal area oval lateral patches between prostomium and peristomium. Pharynx distally surrounded by 10–12 soft papillae, tooth absent. Proventricle in 2–3 setigers, barrel-shaped, tapered posteriorly ( Figs. 27A , 28 A–B); ca. 13–18 rows of muscle cells; post-ventricle with dorsal circlet of cells retaining MG stain ( Fig. 28C ).

Parapodia uniramous, obliquely truncate, usually swollen along posterior edge anterior and posterior lobes lacking ( Figs. 27B , 28 C–D, F), dorsal lobe small; parapodia of setiger 1 shortest, becoming slightly longer over setigers 2–5, then slightly shorter through setiger 9. Elongated internal gland with deeply staining distal tip visible in parapodia of some but not all specimens ( Figs. 27 B–C, 28D, F); some specimens with faintly staining cells along posterior edge of parapodium, likely associated with and obscuring long gland; small glands that stain deeply with MG on surface of parapodia and pygidium, these in a range of sizes from tiny to large ( Fig. 27C ). Dorsal cirri long, thin, retained only on setiger 1, never observed on other setigers. Ventral parapodial cirri slim, slightly wider at base, inserted in middle of parapodium, not exceeding length of parapodium.

All setae compound with long heterogomph shafts, up to 2.5 times length of blade. Setiger 1 with ca. 10–16 setae per parapodium, setigers 2–3 with 14, setigers 4–9 with up to 10 setae; some setae emerging from distal tip of parapodium, remaining setae emerging from ventral face of parapodium between insertion of ventral cirrus and distal tip. Ventral-most blades shortest, 25–75 µm, serrated on proximal portion, serrations clearly visible at 1000x; longer blades up to 300 µm, with very long, fine, drawn-out tips, possibly serrated at base. Parapodia each with up to four aciculae, these with heavy, thick, pointed, or knobby tip, often appearing golden in color, not protruding from parapodia but forming anterior and posterior bumps at distal end.

Pygidium with two ventromedial thin, filiform cirri and two lateral oval cirri, with glandular areas as seen on parapodia ( Figs. 27A , 28E ).

Reproductive specimens with oocytes in setigers 6–9, measuring 50–60 µm in greatest diameter, some squeezing into and filling half of parapodium, others in coelom near parapodia.

Remarks. Anguillosyllis enneapoda n. sp. is most similar to Anguillosyllis inornata n. sp. from offshore California: both species have nine setigers, fused palps, and lack any development of anterior or posterior lobes on the parapodia. However, the pharynx of A. enneapoda n. sp. lacks the deep golden-brown color seen in Anguillosyllis inornata n. sp. Anguillosyllis enneapoda n. sp. has four aciculae per parapodium and these are golden in color and heavier compared with the two aciculae per parapodium of A. inornata n. sp. Some aciculae appear to have a bent or knobby tip, others are clearly straight and pointed but this depends on the angle of view. In some specimens only two or three aciculae could be seen, but in specimens where the tissue was torn or decomposed, four were clearly visible, two each in the anterior and posterior parts of each parapodium. The setal blades of A. enneapoda n. sp. are clearly and more deeply serrated rather than appearing plain or only minimally serrated at very high magnifications as in A. inornata n. sp. The remaining species with nine setigers and fused palps, A. pupa , has large posterior parapodial lobes, which A. enneapoda n. sp. lacks.

Two other species, A. blakei n. sp. and A. sepula n. sp., also have large tubular glands in the parapodia, but those two species have 10 setigers whereas A. enneapoda n. sp. has nine. In A. enneapoda n. sp., the distal tip of the internal parapodial glands has a large-diameter opening that stains deeply with MG whereas in A. blakei n. sp. there is a narrow, nipple-like tip on the gland.

In addition to the deeply staining external glands associated with the parapodia, there are glands in the pygidial segment of A. enneapoda n. sp. that also stain; these glands appear to have a rosette structure similar to that seen in other species such as A. aciculata n. sp. and A. hadra n. sp.

Etymology. From the Greek ennea, meaning nine and podos, meaning foot; in reference to the nine setigers of this species.

Records. South China Sea, off Brunei, 1242–2117 m.

Figures

FIGURE 27. Anguillosyllis enneapoda n. sp. Holotype (MCZ 148506):A, entire specimen, dorsal view; B, setiger 8, dorso-lateral view; C, setigers 8–9 and pygidium, dorso-posterior view, anal cirri removed, inset not to scale. Abbreviations: ExGl—external gland, InGl—internal gland, pyg—pygidium.

FIGURE 28. Anguillosyllis enneapoda n. sp. Holotype (MCZ 148506): A, entire specimen. Paratype (MCZ 148505): B, entire specimen. Holotype (MCZ 148506): C, setigers 1–6, post-ventricle caeca with dorsal ring of stained cells; D, setiger 8; E, setigers 8–9 and pygidium with anal cirri; F, setiger 9. A–F, dorsal view; C–F stained with MG.