Anguillosyllis hampsoni, 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 : 38-40

Anguillosyllis hampsoni n. sp.

Figures 14–15

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Braniella cf. palpata: Maciolek-Blake et al. 1985 .

Material examined. (14 specimens from 3 stations, 10 samples). Western North Atlantic, off Massachusetts, Georges Bank, BIMP Sta. 16, 40°34.2′N, 67°12.3′W, coll. M. Rawson, Lamont-Doherty, Chief Scientist, Cruise M-2, R/V Oceanus , 18 Nov 1981, 142 m, 2 paratypes ( USNM 1480259 ) ; coll. G. Hampson, WHOI, Chief Scientist, Cruise M-4, R/V Cape Henlopen, 12–13 May 1982, 140 m, paratype ( USNM 1480260 ) ; Cruise M-8, R/ V Gyre, 16 May 1983, 139 m, 2 paratypes ( USNM 1480261 ) ; coll. R. Petrecca, Chief Scientist, Cruise M-10, R/V Oceanus , 15 Nov 1983, 142 m, 2 paratypes ( USNM 1480262 ) ; coll. G. Hampson, Chief Scientist, Cruise M-11, R/V Oceanus , 3 Feb 1984, 142 m, paratype ( USNM 1480263 ) . BIMP Sta. 17, 40°35.0′N, 67°11.7′W, coll. M. Rawson, Lamont-Doherty, Chief Scientist, Cruise M-2, R/V Oceanus , 18 Nov 1981, 134 m, paratype ( USNM 1480264 ) ; coll. G. Hampson, Chief Scientist, Cruise M-5, R/V Oceanus , 23 Jul 1982, 135 m, 2 paratypes ( USNM 1480265 ) . BIMP Sta. 18, 40°33.5′N, 67°13.7′W, coll. G. Hampson, Chief Scientist, Cruise M-3, R/ V Endeavor, 17–18 Feb 1982, 145– 147 m, paratype ( USNM 1480266 ) ; Cruise M-5, R/V Oceanus , 23 Jul 1982, 140 m, holotype ( USNM 1480267 ) ; Cruise M-6, R/V Oceanus , 21 Nov 1982, 144 m, paratype ( USNM 1480268 ) .

Description. Body with 11 setigers ( Figs. 14A , 15A ); most specimens ca. 1.0 mm long, maximal length 2.0 mm without anal cirri, maximal width 0.5 mm without parapodia, 1.1 mm with parapodia but without setae. Overall body shape linear ( Fig. 15A ) unless swollen with eggs ( Fig. 14A ), first three setigers with stiff, bristly appearance due to large number of setae. Palps bean-shaped, appear fused (at least ventrally) along proximal two-thirds to three-quarters, tips free, often turned ventrally; prostomium dome-shaped, with three short club-shaped antennae in nearly transverse row, two lateral antennae slightly anterior to medial one; eyes lacking; nuchal area between prostomium and peristomium short, oblong, extending toward midline, cilia obvious. Peristomium with two tentacular cirri, similar to but smaller than antennae; sometimes appearing large or swollen. Eversible pharynx with distal ring of 10 soft papillae. Proventricle in 2–3 setigers, anterior margin straight, widest in middle with slightly narrowing posterior end ( Figs. 14A , 15 A–B); rows of muscle cells indistinct, perhaps 30–35; post-ventricle caeca with numerous dorsal cells retaining MB stain ( Fig. 15A ).

Anterior setigers 1–3 faintly biannulate dorsally, clearly biannulate when stained. Parapodia uniramous, long, rectangular, with small anterior and slightly larger posterior lobes on all setigers ( Fig. 14 C–E); with large dorsal lobe on all setigers, often turned back, appearing as triangular flap ( Fig. 14 C–E). Dorsal cirri long, thin, coiled into tight corkscrews or relaxed, present on all setigers (including setiger 2 on one specimen); with basal cirrophores near posterior margin of parapodium. Ventral cirri inserted midway between body and distal end of parapodia on all setigers, wider at base, tapering toward distal end. No parapodial glands observed but dorsum with areas of dark glandular areas and clear sinuous channels on setigers 5–11.

All setae compound, with heterogomph shafts; several emerging from ventral face of parapodium, others emerging from distal end of parapodium. Setigers 1–3 with ca. 35–40 short-bladed falcigers, blades serrated, with hooked tips, 20–30 µm long ( Fig. 14B ); setigers 1–3 additionally with 2–4 falcigers with longer blades measuring 45–50 µm, these also serrate ( Fig. 14B ); longer-bladed setae becoming more numerous, with blades up to 110 µm long, in middle and posterior setigers. Setal shafts measuring 70–130 µm long. Number of setae decreasing to about 15 in mid-region, 10 in posterior setigers. Each parapodium with stout, pointed acicula in anterior edge and 1–2 aciculae in posterior edge.

Pygidium with four cirri: two flat, oval lateral cirri and two thin, filiform, often coiled ventromedial cirri; all cirri easily lost ( Figs. 14A , 15C ).

Reproductive characteristics. Eggs measuring 50–80 µm were present in several specimens in the coelom after setiger 6 or 7. Specimens with eggs were collected in both November and July.

Remarks. Anguillosyllis hampsoni n. sp. differs from A. palpata principally in the number and type of setae in anterior fascicles as well as in other subtler morphological details. There are three to four times as many shortbladed falcigers in setigers 1–3 in A. hampsoni n. sp. as in A. palpata and many fewer longer-bladed setae, none of which are spiniger-like. The palps of A. hampsoni n. sp. are usually more clearly fused along the ventral surface compared with the palps of A. palpata , although they may appear separate from the dorsal side. Additionally, the proventricle in A. hampsoni n. sp., which is basically the same size as that of A. palpata , is not cordate, but has a straighter anterior margin, and does not taper as abruptly as that of A. palpata . There are no obvious glands in the parapodia in A. hampsoni n. sp. as there are in A. palpata , and the huge lateral nuchal patches seen in A. palpata are much smaller and visible only as dorsal bands between the prostomium and peristomium in A. hampsoni n. sp. Finally, A. hampsoni n. sp. is generally a smaller species than A. palpata .

Etymology. This species is named for Woods Hole Oceanographic Institute scientist Mr. George Hampson (1938–2015), the skilled Chief Scientist on many of the Georges Bank and ACSAR cruises conducted in the 1980s. A friend and colleague, George exemplified the best in enthusiasm, competence, and careful attention to detail that made these sampling cruises a success.

Records. Northwest Atlantic, Georges Bank, 142–151 m.

Figures

FIGURE 14. Anguillosyllis hampsoni n. sp. Paratype (USNM 1480263): A, entire specimen, dorsal view; B, falcigers from setiger 3; C, anterior end including setigers 1 and 2, dorsal view; D, setiger 8, dorsal view; E, setigers 10 and 11, dorsal view. Abbreviations: Acb—acicular bump, aL—anterior lobe, dC—dorsal cirrus, dL—dorsal lobe, nuc—nuchal cilia, pL—posterior lobe, vC—ventral cirrus.

FIGURE 15. Anguillosyllis hampsoni n. sp. Paratype (USNM 1480263): A, entire specimen, dorsal view. Holotype (USNM 1480267): B, anterior end, dorsal view. Paratype (USNM 1480263): C, setiger 11 and pygidium, ventral view. B–C with Shirlastain A.