Anguillosyllis pupa ( Hartman, 1965 )

Maciolek, Nancy J., 2020, Anguillosyllis (Annelida: Syllidae) from multiple deep-water locations in the northern and southern hemispheres, Zootaxa 4793 (1), pp. 1-73 : 66-68

Anguillosyllis pupa ( Hartman, 1965)

Figure 33

Braniella pupa Hartman, 1965: 72–73 , pl. 8; Hartman & Fauchald, 1971: 51.

Anguillosyllis pupa: Aguado & San Martín, 2008: 38 , Figure 2 ; Lucas et al. 2018: 773.

Material examined. (holotype plus 109 specimens in 15 samples from 2 stations) Western Atlantic Slope, off Georges Bank south of Cape Cod . Holotype ( AHF Poly 0168 ), Sta. SL 4, 39°56ʹ30ʺN, 70°39ʹ54ʺW, 400 m, Aug 1962, coll. H.L. Sanders, WHOI .— US North Atlantic ACSAR Program, Sta. 12, coll. G. Hampson, WHOI, Chief Scientist, Cruise North-1, R/V Cape Hatteras , 15 Nov 1984, Rep. 2, 39°54.35ʹN, 70°55.18′W, 558 m, 15 specimens ( USNM 1480245 ) ; Rep. 3 , 39°54.37ʹN, 70°55.18′W, 553 m, 9 specimens ( USNM 1480246 ) ; Cruise North-2, R/V Oceanus , 4 May 1985, Rep. 1 , 39°54.31ʹN, 70°55.04ʹW, 551 m, 10 specimens ( USNM 1480247 ) ; Rep. 2 , 39°54.26′N, 70°55.07′W, 555 m, 7 specimens ( USNM 1480248 ) ; Rep. 3 , 39°54.29′N, 70°55.04′W, 554 m, 8 specimens ( USNM 1480249 ) ; Cruise North-4, R/V Gyre , 30 Nov 1985, Rep. 1, 39°54.28′N, 70°55.12′W, 560 m, 2 specimens ( USNM 1480250 ), 1 ( NJM) ; Rep. 2 , 39°54.28′N, 70°55.12′W, 559 m, 9 specimens ( USNM 1480251 ) ; Rep. 3 , 39°54.32′N, 70°55.12′W, 544 m, 3 specimens ( USNM 1480252 ) ; Cruise North-5 , R/V Cape Hatteras , 06 May 1986, Rep. 1 , 39°54.17′N, 70°55.22′W, 560 m, 2 specimens ( USNM 1480253 ) ; Rep. 2 , 39°54.27′N, 70°55.17′W, 548 m, 11 specimens ( USNM 1480254 ) ; Rep. 3 , 39°54.28′N, 70°55.09′W, 552 m, 2 specimens ( USNM 1480255 ) ; Cruise North-6 , R/V Cape Hatteras , 30 July 1986, Rep. 1 , 39°54.25′N, 70°55.04′W, 563 m, 10 specimens ( USNM 1480256 ) ; Rep. 2 , 39°54.26′N, 70°55.07′W, 559 m, 7 specimens ( USNM 1480257 ) ; Rep. 3 , 39°54.24′N, 70°55.09′W, 563 m, 9 specimens ( USNM 1480258 ) (2, NJM) . Gulf of Maine , coll. G. Hampson, WHOI, Chief Scientist, BIMP Sta. 14A , 41°57.5ʹN, 68°31.0ʹW, 165 m, Jul 1982, 2 specimens ( USNM 1480244 )

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Description. Body with 9 setigers; maximal length 2 mm without anal cirri, width 0.3–0.4 mm without parapodia, 0.6–0.75 mm including parapodia but without setae, most specimens 1 mm long, 0.5 mm wide. Palps completely fused, short, broad, anterior margin wide and gently rounded ( Fig. 33A ), occasionally slightly pointed, sometimes with tiny medial notch. Prostomium elliptical, wider than long; eyes lacking; three oval antennae in transverse row on posterior half of prostomium; peristomium shorter than prostomium, clearly demarcated, with two short tentacular cirri. Nuchal cilia not visible even when stained with Shirlastain A. Eversible pharynx distally surrounded by 10 long, soft papillae, tooth absent. Proventricle in three setigers, spherical in two setigers and usually tapered in third; rows of muscle cells difficult to discern, ca. 20–25 (fide Aguado & San Martín 2008); post-ventricle with dorsal circlet of cells retaining MG stain.

Parapodia uniramous, elongated, rectangular; with very small anterior lobe present in anterior setigers, essentially absent in posterior setigers ( Fig. 33 B–K); posterior lobe small in anterior setigers, becoming much larger over subsequent setigers ( Fig. 33 B–K); dorsal lobe small, difficult to observe; parapodial glands not observed except in the large posterior lobes. Dorsal cirri with basal cirrophore ( Fig. 33 A–B), cirri extremely long, thin, tightly coiled into corkscrew or relaxed, absent on setiger 2. Ventral cirri slender, inserted in middle of parapodium ( Fig. 33I ).

Anterior setigers with ca. 12–18 setae, setiger 1 with slightly fewer setae than setigers 2–5; number of setae after setiger 5 up to 6–10 per parapodium. All setae composite with heterogomph shafts, blades include ventral falcigers and dorsal spiniger-like setae; all blades with fine to medium serrations on proximal part of blade, these most obvious at 1000x. Falcigers with blunt, slightly hooked tips, emerging in two rows from ventral face of parapodium between insertion of ventral cirrus and distal tip of parapodium; blades measuring 30–85 µm. Spiniger-like setae with fine, sinuous tips, emerging from distal end of parapodium; blades measuring 75–95 µm in setiger 1, 110– 140 µm in setigers 2–6, 110– 120 µm in setigers 7–9. Parapodia each with two aciculae, not protruding but forming anterior and posterior bumps (e.g., Fig. 33F ).

Pygidium with four anal cirri: two ventromedial, filiform, coiled and two lateral, oval, glandular ( Fig. 33 L–M); anus surrounded by fine cilia.

Reproductive specimens collected in November 1984; oocytes present from setiger 6 onward, on either side of midline, pressed up against parapodia, measuring 70–95 µm greatest diameter. Specimens collected in May 1985 without eggs but included one very small 8-setiger specimen that may be a juvenile.

Remarks. Anguillosyllis pupa was described by Hartman (1965) from collections made by Dr. Howard L. Sanders of the Woods Hole Oceanographic Institution (WHOI) in the early 1960s during his pioneering investigations of deep-sea benthic fauna retained by fine 300-µm-mesh screens. Most of the new material examined here was collected at a station (ACSAR North 12) close to the type locality (Sanders’ Sta. SL4). Lucas et al. (2018) referred 41 specimens of Anguillosyllis collected from five stations off Norway to A. pupa ; these specimens were collected mostly from Rijpfjord in 128– 366 m.

The new materials agree well with the holotype, with the following additions to the original description, some of which were also noted by Aguado & San Martín (2008): (1) the distal end of the pharynx is surrounded by soft papillae rather than lacking papillae, (2) both falcigers and spiniger-like setae are present, rather than only spinigers, (3) the setae are finely serrated rather than smooth, (4) the ventral cirri are inserted halfway along the parapodia rather than at the base, and (5) the pygidium has four anal cirri rather than two.

Aguado & San Martín (2008) refer to the holotype in their redescription, but their material examined does not include any type material: the holotype is deposited in the Allan Hancock Foundation, LA County Museum, and is the only designated type specimen for this species. They noted the serrations on the blades of the setae and the presence of falcigers as well as spiniger-like setae but reported shorter blades than measured here (spinigers 95 µm vs. 140 µm and falcigers 10 µm vs. 30 µm).

In her description of the genus (as Braniella ), Hartman (1965: 274) wrote that the ventral cirri are “similar (to the dorsal cirri) but much shorter and slenderer” and were “inserted at the base” of the parapodia; the illustration of a median parapodium ( Hartman 1965: Plate 8b, p. 275) shows the ventral cirrus inserted at the base of the parapodium, but thicker than the dorsal cirrus. In my examination of the holotype and new material, the ventral cirri were noted to be as slender as the dorsal cirri but inserted halfway along the parapodia on all setigers; occasionally, the ventral cirrus on setiger 1 appeared to be at the base of the parapodium, but this is possibly an artifact due to the parapodium being pulled in toward the body of some specimens at the time of fixation.

Only a few specimens of A. pupa had a full complement of four anal cirri, with 0–3 usually being noted on any one individual. The arrangement of two slender, usually coiled, cirri in a ventromedial position and two lateral, oval, glandular-appearing cirri as figured here for A. pupa is also typical for all other members of the genus.

Other Anguillosyllis species with nine setigers include A. enneapoda n. sp. from the South China Sea and A. inornata n. sp. from off California. These species differ from A. pupa in: (1) having narrower, anteriorly pointed fused palps rather than palps softly rounded on the anterior margin and (2) lacking the large posterior parapodial lobes seen in A. pupa . The depth distribution of the three species also differs, with A. pupa occurring in shallower shelf and upper slope depths than almost all other species of Anguillosyllis .

Records. Gulf of Maine , 168 m ; off New England, 400–550 m ; off Delaware , 183 m ( USNM 56762 ); off northeast South America, 770–805 m (fide Hartman 1965) ; off Norway, 128–366 m (fide Lucas et al. (2018).

Figures

FIGURE 2. Anguillosyllis palpata (Hartman, 1967). Antarctica, ANDEEP sta. 74-5 (SMF 24873), parapodia, ventral view: A, setiger 1; B, setiger 2; C, setiger 3; D, setiger 4; E, setiger 5; F, setiger 6; G, setiger 7; H, setiger 9; I, setiger 11. Abbreviations: aL—anterior lobe, dL—dorsal lobe, pL—posterior lobe, vC—ventral cirrus.

FIGURE 33. Anguillosyllis pupa (Hartman, 1965). Specimen from USNM 1480249:A, anterior end; B, setiger 1; C, setiger 2; D, setiger 3; E, setiger 4; F–G, setiger 5 from right and left sides; H, setiger 6; I, setiger 7; J, setiger 8; K, setiger 9; L, pygidium and anal cirri. A–H, J–L: dorsal view, I: ventral view. Another specimen from USNM 1480249: M, pygidium and anal cirri, ventral view. Abbreviations: Acb—acicular bump, aL—anterior lobe, dL—dorsal lobe, InGl—internal gland, pL—posterior lobe, vC—ventral cirrus.