Anguillosyllis bruneiensis, 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 : 51-53

Anguillosyllis bruneiensis n. sp.

Figure 24

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Material examined. South China Sea, off Brunei. Coll. J.A. Blake. Sta. 46, 2 Jun 2011, 5 o 48′02.68476″N, 114 o 18′10.00693″E, 1234 m, 1 specimen, holotype ( MCZ 147936 ) .

Description. Body with 8 setigers ( Fig. 24A ), colorless; 1 mm long without anal cirri, 0.2 mm wide without parapodia, 0.4 mm wide with parapodia but excluding setae, posterior half distorted with eggs. Palps completely fused, anterior margin wide, softly rounded with slight medial indentation; eyes lacking; prostomium oval, with three club-shaped antennae; peristomium shorter but wider than prostomium, with two short, oval tentacular cirri. Nuchal area between prostomium and peristomium visible when stained with Shirlastain A. Proventricle in 2+ setigers, bluntly barrel-shaped anteriorly, tapered posteriorly, rows of muscle cells indistinct, ca. 20; post-ventricle caeca retaining MG stain on dorsal circlet of cells.

Parapodia uniramous, shortest on setiger 1, becoming longer, rectangular, over next few setigers; small anterior lobe present on all setigers; posterior lobe small on setigers 1–2, becoming larger through setiger 8 ( Fig. 24A ); dorsal lobe not observed; large clear cell or gland present in parapodium near base of ventral cirrus. Dorsal cirri present on setigers 4–7, others lost but basal cirrophores present on setigers 1, 3, and 8; ventral cirri short, digitiform, inserted in middle of parapodium.

All setae compound with heterogomph shafts; setiger 1 with 18–20 setae, setigers 2–7 with 20–22, setiger 8 with ca. 10 setae. Several setae emerge from distal tip, others from ventral face of parapodium. All blades with roughened proximal edge seen only with Phase Contrast at 1500x, terminating in pointed tips, length of blades 30–120 µm ( Fig. 24 B–C). Aciculae not seen.

Pygidial cirri lost, except one small oval cirrus possibly regenerating.

Oocytes in coelom of setigers 5–7, measuring 50–75 µm in greatest diameter; some oocytes entering or within parapodia ( Fig. 24A ).

Remarks. Anguillosyllis bruneiensis n. sp. from the South China Sea is, along with A. andeepia n. sp. from the Antarctic, reproductively mature with only eight setigers, thus precluding the possibility that these are juveniles of other species. The two species differ from each other principally in that A. bruneiensis n. sp. has a peristomium that is shorter rather than longer than the prostomium and fused palps that are short, wide, and anteriorly rounded rather than elongated and pointed anteriorly. Also, A. bruneiensis n. sp. lacks the obvious golden aciculae of A. andeepia n. sp.

Etymology. The species epithet reflects the collection location off Brunei in the South China Sea.

Records. South China Sea, 1234 m.

Figures

FIGURE 24. Anguillosyllis bruneiensis n. sp. Holotype (MCZ 147936): A, entire specimen, dorsal view; B–C, setae, inset not to scale.