Polycirrus cf. denticulatus Saint-Joseph, 1894

Lavesque, Nicolas, Hutchings, Pat, Daffe, Guillemine & Londoño-Mesa, Mario H., 2020, Revision of the French Polycirridae (Annelida, Terebelliformia), with descriptions of eight new species, Zootaxa 4869 (2), pp. 151-186 : 161

Polycirrus cf. denticulatus Saint-Joseph, 1894

Figures 6–7 , Table 2.

Material examined: AM W.53114, incomplete, NE Atlantic, Bay of Biscay , Bay of Brest, 48°21’28”N, 4°26’38”W, 7 m depth, May 2018 , mounted for SEM, some parapodia used for molecular analysis. AM W.53115, incomplete, NE Atlantic, Bay of Biscay , Bay of Brest, 48°21’28”N, 4°26’38”W, 7 m depth, May 2018 , mounted for SEM, some parapodia used for molecular analysis. MNHN-IA-PNT 121, incomplete, English Channel , Morlaix Bay, 48°41’04”N, 3°54’58”W, intertidal, February 2016 . SMA_ BR _ Poly _17, incomplete, English Channel, 48°35’50”N, 4°37’27”W, intertidal, February 2015 . SMA_ BR _ Poly _14, incomplete, English Channel, 48°35’50”N, 4°37’27”W, intertidal, February 2015 .

Description. Transverse prostomium attached to dorsal surface of base of upper lip; basal part as thick semicircular crest across dorsum, extending lateral and posteriorly ( Fig. 6B ), covering SG1 laterally and terminating lateral to lower lip. Distal part extending along lip, terminating subdistally.

Few buccal tentacles remaining, short and thick, cylindrical ( Figs 6A ; 7A ). Peristomium forming lips; upper lip comprising single medial lobe only, margin of lobe thickened and overturned ( Figs 6 A–C; 7A). Outer lower lip shield-like, subtriangular and pointing toward mouth, longer than wide, ridged and grooved, extending posteriorly to segment 3 ( Figs 6A ; 7A ).

SG1 and 2 reduced, SG1 visible dorsally and laterally, SG2 visible dorsally, laterally and ventrally ( Fig. 6A ); body slightly broader until SG5, gently tapering until SG10, then of relatively uniform width, cylindrical ( Fig. 6B ). Ventro-lateral inflated pads well-defined from SG3 to SG10, smooth and transversely ridged, subsequent ones less conspicuous until mid-body ( Figs 6A, C ; 7A ). Deep mid-ventral groove from SG3 ( Figs 6A ; 7A ).

Notopodia from SG3, extending for 12–13 segments, until SG14–15. Notopodia more-or-less rectangular, lobes slightly triangular (distally rounded) ( Fig. 7 B–C). Narrowly-winged notochaetae of two distinct lengths, slightly expanded subdistally, with fine tips ( Figs 6 D–E; 7B–C). Neuropodia beginning from SG12; type of uncini not seen (specimen used for SEM), crest with single elongate and sharp tooth on first row above main fang, with at least one additional row of shorter, irregularly sized teeth at base (exact number of additional rows not visible) ( Fig. 7D ).

Nephridial and genital papillae present on segments 3–8, ventral to bases of notopodia ( Fig. 6C ).

Pygidium unknown.

Habitat. Shallow waters, in maerl (rhodolith) beds, seagrass beds (this study) and among laminarians, algae, serpulids, and hydrozoa ( Gil 2011).

Type locality. Brittany, France (exact locality problematic) .

Distribution. NE Atlantic, English Channel, Mediterranean Sea ( Fauvel 1927; Gil 2011), Adriatic Sea ( Mikac 2015).

Remarks. French specimens, sampled close to the potential type locality, match almost completely with the recent redescription of type material by Glasby & Hutchings (2014). However, few minor variations were observed: mid-ventral groove appearing on segment 3 (instead of segment 4), notochaetigerous segments 12–13 (instead of 10, but type material is broken). Finally, we also document the first segment on which neuropodia begin.

As commented by Glasby & Hutchings (2014), doubts exist about the location of the type material. Indeed, the holotype seems to have been sampled in Concarneau (Brittany, Bay of Biscay) while in the original description Mr le Baron de St. Joseph (1894) reported the type locality in Dinard (Brittany, English Channel). Moreover, the redescription of the holotype does not fit exactly the type description ( Glasby & Hutchings 2014). Consequently, until a neotype is collected and described, we prefer to identify these specimens as Polycirrus cf. denticulatus .

Figures

FIGURE 6. Polycirrus cf. denticulatus, material examined SMA_Br_Poly_17 (A), SMA_Br_Poly_14 (B–E). A. Anterior end, ventral view; B. Anterior end, dorsal view; C. Anterior end, lateral view; D. Notochaetae, SG6, 10x objective; E. Notochaetae, SG6, 100x objective. Abbreviations: Ll, lower lip; Pr, prostomium; Np, nephridial papilla: Ul, upper lip. Numbers refer to segments.

FIGURE 7. Polycirrus cf. denticulatus, SEM, material examined AM W.53114 (A, C), AM W.53115 (B, D). A. Anterior end, ventral view; B. Notopodia, SG3–4, ventral view; C. Notochaetae, SG4–5; D. Abdominal uncini. Abbreviations: Bt, buccal tentacle; Ll, lower lip; Ul, upper lip.