Anguillosyllis taleola, 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 : 41-44

Anguillosyllis taleola n. sp.

Figures 16–17

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Material examined. (14 specimens from 10 stations) South China Sea, off Brunei. Coll. J.A. Blake. Sta. 19, 5 Jun 2011, 5°47′28.77291″N, 114°09′18.99869″E, 1487 m, 2 specimens ( MCZ 150599 ) ; Sta. 44, 2 Jun 2011, 5°47′22.97393″N, 114°15′36.22932″E, 1294 m, paratype ( MCZ 150600 ) . Coll. P.A. Neubert, Sta.AN 8, 27 Jun 2011, 5°27′56.15653″N, 113°45′42.93641″E, 1783 m, 3 paratypes ( MCZ 150601 ) ; Sta. DA2, 1 Jul 11, 5°24′13.64904″N, 113°28′04.25708″E, 1760 m, paratype ( MCZ 150598 ) ; Sta. DA5, 1 Jul 11, 5°26′21.37195″N, 113°28′35.58907″E, 1958 m, 2 specimens ( MCZ 150602 ) ; Sta. JA1, 30 Jun 2011, 5°28′22.57522″N, 113°36′38.54386″E, 1888 m, 1 specimen ( MCZ 150603 ) ; Sta. JA2 , 30 Jun 11, 5°27′55.53448″N, 113°32′57.69642″E, 1954 m, 1 specimen ( NJM) ; Sta. JA3 , 3 Jul 2011, 5°29′25.34994″N, 113°34′52.03519″E, 1922 m, 1 specimen ( MCZ 150604 ) ; Sta. ME13, 26 Jun 2011, 5°23′16.81208″N, 113°37′16.44011″E, 1777 m, holotype ( MCZ 150597 ) ; Sta. ME16, 26 Jun 2011, 5°24;24.44585″N, 113°35;28.03023″E, 1805 m, 1 specimen ( MCZ 150605 ) .

Description. Body with 10 setigers ( Figs. 16A , 17 A–B), colorless, delicate; holotype 2 mm long without anal cirri; other specimens including paratypes 1 mm long; maximum width 0.2 mm without parapodia, 0.5–0.6 mm with parapodia but excluding setae. First 5–6 setigers may be short, setigers 6–10 longer, more widely separated, or body may appear linear with setigers of relatively equal length ( Fig. 17 A–B). Palps elongate, bean-shaped, completely separate; prostomium wider than long, appearing to be faintly divided into two parts with smaller inner part domeshaped, slightly raised and outer part inflated, surrounding inner part like a collar ( Figs. 16 A–B, 17D); three large club-shaped antennae on outer part, eyes lacking; peristomium slightly inflated, with two large tentacular cirri. Nuchal cilia in obvious patches between prostomium and peristomium. Proventricle filling body cavity in 3–4 setigers, cylindrical to barrel-shaped, with slightly rounded or straight anterior edge, very slightly narrowed at posterior end ( Figs. 16A , 17 A–C); rows of muscle cells particularly indistinct even under high power, ca. 18 irregular darker areas; post-ventricle caeca not retaining MG stain.

Parapodia uniramous, shortest on setiger 1, becoming longer, rectangular over subsequent setigers, after setiger 5 becoming elongated, slim, with rounded distal end; small anterior lobes present on setigers 1–4 ( Figs. 16C , 17E ), lobes becoming smaller and absent on subsequent setigers; posterior lobes lacking but posteroventral portion of parapodia may bulge with possibly glandular structures; dorsal lobe small, rounded ( Fig. 16C ). Dorsal cirri (or basal cirrophore) present on setiger 1 ( Fig. 17 A–C), other cirri absent or lost; ventral cirri short, wider at base then tapered, inserted in middle of parapodium. No elongated parapodial glands observed, but most specimens with fleshy looking posteroventral area of parapodia that might contain glands ( Fig. 17E ).

Setae emerging in fan-shaped fascicle from distal tip and ventral face of parapodium, all setae compound, with long heterogomph shafts measuring from ca. 70 µm up to 240 µm, shafts equal in length to blade or may be up to 4 times as long as blade, this especially noticeable in posterior setigers. Blades ranging in length from short falcigers 36–60 µm with blunt, rounded tip in ventral position to long spiniger-like blades up to 120 µm with fine, pointed tips, in dorsal position ( Fig. 17E ); all blades serrated. Setiger 1–5 of holotype with ca. 30 or more setae, becoming less numerous moving posteriorly; setiger 10 with ca. 15–20 setae; other, smaller, specimens with many fewer setae per setiger. Parapodia each with 3–4 aciculae, not emerging but forming anterior and posterior bumps at distal end of parapodia; one acicula with bent tip, others pointed.

Pygidium with four cirri: two large oval glandular lateral cirri and two ventromedial, filiform cirri ( Figs. 16A, D ; 17B, F ).

Reproductive features. Several specimens had eggs moving into the parapodia after setiger 5; these eggs were not measured as they were distorted in the parapodia and eggs in the coelom were indistinct.

Remarks. Anguillosyllis taleola n. sp. is similar to A. palpata in having dorsally separate palps and an obvious nuchal patch; but differs in having 10 rather than 11 setigers, lacking posterior parapodial lobes, and having plain rather than hooked tips on the falcigers. Anguillosyllis taleola n. sp. is similar to A. denaria n. sp. in having 10 setigers, but A. denaria n. sp. has palps that are fused halfway rather than completely separate and has large glandular posterior parapodial lobes that are absent in A. taleola n. sp. The nuchal patches of A. taleola n. sp. are large and obvious rather than inconspicuous as in A. denaria n. sp. Similarly, A. taleola n. sp is similar to A. sepula n. sp. in having 10 setigers and lacking posterior parapodial lobes, but A. sepula n. sp. (see next section) has completely fused palps and setae with shafts that are shorter relative to blade length. Anguillosyllis taleola n. sp. is also similar to A. denaria n. sp. and A. carolina n. sp., both of which have 10 setigers, in having a two-part appearance to the prostomium, with a smaller medial portion surrounded by an inflated area that bears the antennae.

Anguillosyllis taleola n. sp. differs from most other Anguillosyllis species in having setae with very long shafts relative to the blade length ( Table 3 ). The shafts may be equal in length to the longest blades or up to four times the length of the shortest blades. In other species of Anguillosyllis , the shafts are not as long relative to blade length; in A. palpata the shafts may be up to three times as long as the blades but in other species they may be up to only as twice as long.

Etymology. The specific name, taleola , is the diminutive of the Latin talea, for slender staff or rod; it refers to the relatively long shafts of the setae in this species.

Records. South China Sea, off Brunei; 1294–1958 m.

Figures

FIGURE 16. Anguillosyllis taleola n. sp. Paratype (MCZ 150598): A, entire specimen, dorsal view. Holotype (MCZ 150597): B, prostomium and peristomium, dorsal view; C, setigers 2–3, dorsal view; Paratype (MCZ 150598): D, setiger 10 and pygidium, ventral view. Abbreviations: aCL—anal cirrus lateral, aCF—anal cirrus filiform, aL—anterior lobe, dL—dorsal lobe, ip—inner prostomium, op—outer prostomium, vC, insertion point of ventral cirrus.

FIGURE 17. Anguillosyllis taleola n. sp. Holotype (MCZ 150597): A, entire specimen, dorsal view. Paratype (MCZ 150598): B, entire specimen, ventral view. Holotype (MCZ 150597): C, anterior end, dorsal view; D, palps, inner and outer prostomium, and peristomium, dorsal view; E, setigers 2–4, dorsal view; F, posterior end, ventral view. Dark spot near base of proventricle in A and C is stained ingested material rather than cells of post-ventricle caeca. Abbreviations: pa—palp, ip—inner prostomium, op—outer prostomium.