Anguillosyllis denaria, 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 : 32-35

Anguillosyllis denaria n. sp.

Figures 10 B–E, 11

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Material examined. (39 specimens from 23stations) South China Sea,off Brunei. Coll.J.A.Blake.Sta. 6, 7Jun2011, 5°51′40.17938″N, 114°10′54.32730″E, 1353 m, 2 specimens ( MCZ 151148 ) ; Sta. 9, 6 Jun 2011, 5°52′38.23770″N, 114°13′42.28254″E, 1459 m, paratype ( MCZ 151147 ) ; Sta. 21, 5 Jun 2011, 5°50′25.56269″N, 114°12′30.71125″E, 1424 m, 1 specimen ( MCZ 151149 ) ; Sta. 29, 4 Jun 2011, 5°43′01.15997″N, 114°06′07.18190″E, 1537 m, 1 specimen ( MCZ 151150 ) ; Sta. 33, 4 Jun 2011, 5°48′54.28228″N, 114°14′02.81573″E, 1370 m, 2 specimens ( MCZ 151151 ) ; Sta. 34, 4 Jun 2011, 5°50′32.29819″N, 114°15′47.44656″E, 1369 m, holotype ( MCZ 151152 ) ; Sta. 35, 3 Jun 2011, 5°47′37.12906″N, 114°14′10.75153″E, 1329 m, 2 specimens ( MCZ 151153 ) ; Sta. 40, 3 Jun 2011, 5°41′48.58019″N, 114°08′57.21297″E, 1379 m, 2 paratypes ( MCZ151154 ) ; Sta. 42, 3 Jun2011, 5°45′13.06236″N, 114°13′06.77111″E, 1252 m, 2 specimens ( MCZ 151155 ) ; Sta. 44, 2 Jun 2011, 5°47′22.97393″N, 114°15′36.22932″E, 1294 m, 1 speci- men ( MCZ 151156 ) ; Sta. 45, 2 Jun 2011, 5°48′57.88185″N, 114°17′18.08262″E, 1260 m, 2 specimens (poor con- dition) ( MCZ 151157 ) ; Sta. 48, 2 Jun 2011, 5°45′28.93802″N, 114°15′23.44165″E, 1219 m, 2 specimens ( MCZ 151158 ) ; Sta. 49, 2 Jun 2011, 5°44′24.32540″N, 114°13′59.60803″E, 1199 m, paratype ( MCZ 151159 ) ; Sta. 50, 2 Jun 2011, 5°42′55.91978″N, 114°12′23.51666″E, 1214 m, 2 specimens ( MCZ 151160 ) ; Sta. 51, 1 Jun 2011, 5°41′53.71760″N, 114°10′26.14608″E, 1308 m, 1 specimen ( MCZ 151161 ) ; Sta. 54, 9 Jun 2011, 5°42′10.95536″N, 114°13′11.98424″E, 1171 m, 2 specimens ( MCZ151162 ) ; Sta. 56, 1 Jun 2011, 5°45′04.58388″N, 114°16′27.71012″E, 1179 m, 1 specimen ( MCZ 151163 ) ; Sta. 61 , 31 May 11, 5°40′32.90422″N, 114°13′15.64893″E, 1050 m, 1 specimen ( NJM) , Sta. WH-Jokit-NE , 6 Jun 2011, 5°53′28.38401″N, 114°11′57.24436″E, 1400 m, 3 specimens ( MCZ 151164 ) . Coll. P. Neubert, Chief Scientist, Sta. JA4, 30 Jun 2011, 5°30′54.36931″N, 113°37′21.11932″E, 1967 m, 2 specimens (NJM); Sta. TU2, 24 Jun 2011, 5°18′25.22812″N, 113°48′13.59077″E, 1224 m, paratype ( MCZ 151165 ) ; Sta. TU7, 4 Jul 2011, 5°19′24.21956″N, 113°47′15.61845″E, 1327 m, 3 specimens ( MCZ 151166 ) ; Sta. TU9, 23 Jun 2011, 5°23′40.02974″N, 113°51′04.16812″E, 1306 m, 2 specimens ( MCZ 151167 ) ; Sta. TU10, 23 Jun 2011, 5°24′42.72532″N, 113°51′35.81868″E, 1354 m, 2 specimens (NJM).

Description. Body with 10 setigers ( Figs. 10B , 11A ), colorless, delicate, linear in shape; maximum size 1.9 mm (holotype 1.5 mm) long without anal cirri, 0.3 mm wide without parapodia, 0.6 mm wide with parapodia but excluding setae. Palps fused both dorsally and ventrally on proximal half to two-thirds, tips free, rounded, faint medial furrow visible on some specimens ( Fig. 11A ); eyes lacking; prostomium more-or-less oval in shape, with three oval to club-shaped antennae, medial antenna slightly longer than lateral antennae; peristomium slightly inflated, with two short oval tentacular cirri. Nuchal cilia in lateral patches between prostomium and peristomium. Proventricle in two or three setigers, barrel-shaped with blunt anterior edge, slightly tapered posteriorly ( Figs. 10 B–C, 11A), rows of muscle cells indistinct at either end, numbering ca. 14–20; post-ventricle caeca surrounding posterior proventricle, with dorsal oval loop of cells retaining MG stain ( Fig. 10C ).

Parapodia uniramous, shortest on setiger 1, becoming longer, rectangular over next few setigers; small anterior lobe present on all setigers, largest on middle setigers then becoming very small ( Fig. 11 B–E); posterior lobe small on setiger 1, becoming increasingly larger through setiger 10, especially large, with large gland(s) on setigers 8–10 ( Fig. 11 B–E); dorsal lobe small, rounded knob on all setigers. Several internal parapodial glands present in setigers 5–10, elongated, intertwined, appearing to exit through dorsal lobe ( Figs. 10E , 11 D–E). Dorsal cirri present on setiger 1 on most specimens, cirri or basal cirrophores of cirri seen on setigers 3–10; ventral cirrus short, wider at base then tapered, inserted in middle of parapodium.

All setae compound with heterogomph shafts; most setae emerge from distal tip, several others from ventral face of parapodium. Ventral blades shorter with narrow, blunt tips, 22–45 µm in length; longer dorsal spiniger-like blades with fine, pointed tips, up to 120 µm long; all blades with serrated proximal area. Setigers 1–8 with ca. 18–20 setae, setigers 9–10 with 8–12 setae. Parapodia each with at least two, possibly three, 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 and two filiform ventromedial ( Figs. 10B, E , 11A ).

Oocytes in coelom of setigers 6–9 ( Fig. 10B, D ), measuring 50–85 µm greatest diameter (ave.= 59.8 ± 8.9 µm, n=20); large oocytes entering parapodia ( Fig. 10A ).

Remarks. Anguillosyllis denaria n. sp. has palps that are fused both dorsally and ventrally for half to 2/3 their length; a faint median furrow is visible on some specimens. The separate tips of the palps are softly rounded rather than narrow as in A. palpata , but may be elongated, thus appearing narrow, or contracted, thus appearing shorter and wider. The only other Anguillosyllis species with similar palps is A. truebloodi n. sp., described below; all other species have palps that are either completely free dorsally or are completely fused except for the very tip. Anguillosyllis denaria n. sp. is similar to A. carolina n. sp. and A. taleola n. sp. in having 10 setigers but differs from both in having large posterior lobes and small nuchal patches, rather than absent or small posterior lobes and large nuchal patches.

The setal blades of A. denaria n. sp. have blunt to fine tips, but are never hooked or hooded as they are in A. palpata and A. hampsoni n. sp. The cells that retain MB stain in the post-ventricle tend to form a loose loop rather than a tight circle as seen in A. palpata and other species.

Etymology. From the Latin adjective denaria , meaning “containing ten each;” in reference to the ten setigers of this species.

Records. South China Sea, off Brunei; 1171–1967 m.

Figures

FIGURE 10. Anguillosyllis carolina n. sp. Holotype (USNM 1480214): A, anterior end, dorsal view.—Anguillosyllis denaria n. sp. Holotype (MCZ 151152): B, entire specimen, dorsal view. Paratype (MCZ 151147): C, setigers 1–5, dorsal view, pharynx, proventricle and post-ventricle MG-stained cells. Holotype (MCZ 151152): D, eggs in coelom of setigers 7–9. Paratype (MCZ 151152): E, setigers 9–10 and pygidium.

FIGURE 11. Anguillosyllis denaria n. sp. Holotype (MCZ 151152): A, entire specimen, dorsal view. Paratype (MCZ 151147): B, setiger 1; C, setiger 2. Holotype (MCZ 151152): D, setiger 7; E, setiger 10. Abbreviations: Acb—acicular bump, aCL—anal cirrus lateral, aCF—anal cirrus filiform, aL—anterior lobe, dC—dorsal cirrus, dL—dorsal lobe, InGl—internal gland, MGstcells stained with Methyl Green, mscBn—muscle bundle, pL—posterior lobe, vC—ventral cirrus.