Polycirrus glasbyi, Lavesque & Hutchings & Daffe & Londoño-Mesa, 2020

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 : 164-165

Polycirrus glasbyi n. sp.

Figures 8–9 , Table 2.

Material examined: Holotype: MNHN-IA-TYPE 2010, complete, NE Atlantic, Bay of Biscay , Arcachon Bay, Comprian, 44°40’33”N, 1°06’28”W, 9 m depth, April 2018 . Paratypes: AM W.53116, one specimen, complete, NE Atlantic , Bay of Biscay, Arcachon Bay, Comprian, 44°40’33”N, 1°06’28”W, 9 m depth, April 2018. AM W.53117, one specimen, incomplete, gravid, NE Atlantic, Bay of Biscay , Arcachon Bay, Comprian , 44°40’33”N, 1°06’28”W, 9 m depth, April 2018. MNHN-IA-TYPE 2011, one specimen, incomplete, NE Atlantic, Bay of Biscay , Arcachon Bay, Comprian , 44°40’33”N, 1°06’28”W, 9 m depth, April 2018. MNHN-IA-TYPE 2012, one specimen, incomplete, NE Atlantic, Bay of Biscay , Arcachon Bay, Comprian , 44°40’33”N, 1°06’28”W, 9 m depth, April 2018. AM W.53118, one specimen, complete, NE Atlantic , Bay of Biscay, Arcachon Bay, Jacquet, 44°43’08”N, 1°10’59”W, 9 m depth, December 2018, mounted for SEM .

Additional material. SMA_Arc_Poly_08, one incomplete specimen, NE Atlantic, Bay of Biscay , Arcachon Bay , Piraillan, 44°43’15”N, 1°10’45”W, 7 m depth, October 2017. SMA_Arc_Poly_09, one incomplete specimen, NE Atlantic, Bay of Biscay , Arcachon Bay , Piraillan, 44°42’17”N, 1°13’15”W, 9 m depth, October 2017, posterior part used for molecular analysis. SMA_Arc_Poly_10, one incomplete specimen, NE Atlantic, Bay of Biscay , Arcachon Bay , Piraillan, 44°42’17”N, 1°13’15”W, 9 m depth, October 2017, posterior part used for molecular analysis. SMA_Arc_Poly_11, one incomplete specimen, NE Atlantic, Bay of Biscay, Arcachon Bay, Piraillan, 44°42’17”N, 1°13’15”W, 9 m depth, October 2017, posterior part used for molecular analysis .

Description. Small species, holotype complete, 12.0 (0.7–12.2) mm long and 0.8 (0.6–1.1) mm wide.

Transverse prostomium attached to dorsal surface of base of upper lip; basal part as thick semicircular crest across dorsum, extending lateral and posteriorly, covering SG1 and 2 laterally and terminating lateral to lower lip. Buccal tentacles of two types, long and thin tentacles uniformly cylindrical, long and thick ones deeply grooved ( Fig. 8 A–B, D). Peristomium forming lips; upper lip elongate, longer than wide, folded into three lobes with a clear triangular shape (middle lobe very elongated) ( Figs 8 A–C; 9A); lower lip oval and inflated, wider then long, very glandular and ridged ( Figs 8 A–C; 9A).

SG1 and 2 reduced, only visible dorsally but hard to see; body with uniform width until mid-body, slightly tapering after ( Fig. 8D ). Ventro-lateral inflated pads present from SG3 to SG9 (SG8), well-defined, smooth and transversely ridged, not separated by a gap ( Figs 8A, C ; 9A ). Anterior midventral groove present until end of body as a stripe, narrow between anterior ventral shields ( Figs 8A, C ; 9A ).

Notopodia from SG3, extending for 19 (18–22) segments, until SG21 (SG20–24); distinctly elongate, rectangular, first pair slightly shorter, bilobed, postchaetal lobe digitiform, larger than prechaetal one ( Fig. 9B ). Winged notochaetae of two distinct lengths, wings present at the distal half of notochaetae, tips whip-like ( Figs 8E ; 9 B–C). Neuropodia beginning from SG10 (9–11); uncini with short occipitum and slightly convex base (Type 1) ( Fig. 8F ), crest with single elongate and sharp tooth on first row above main fang, with two additional rows of shorter, irregularly sized teeth at base ( Fig. 9D ), subrostral process present as low protuberance ( Fig. 8F ).

Nephridial and genital papillae not seen.

Pygidium rounded.

Etymology. This species is dedicated to Chris Glasby, for his friendship and for his great contributions to the knowledge of terebellids and Polycirrus species.

Habitat. Subtidal (5–9 m depth), muddy sands, sheltered waters. Many specimens found inside Bittium reticulatum ( da Costa, 1778) shells ( Fig. 8B ).

Type locality. Arcachon Bay , Bay of Biscay, NE Atlantic Ocean, France .

Distribution. Only known from type locality.

Remarks. Polycirrus glasbyi n. sp. is characterized by the presence of notopodia extending for 18–22 segments which is similar to P. plumosus (17–19 segments) and P. nogueirai n. sp. (16–21 segments) ( Table 2).

Polycirrus glasbyi n. sp. differs from P. plumosus by the first appearance of neuropodia (SG9–11 for P. glasbyi n. sp., SG18–20 for P. plumosus ), by the shape of upper lip (triangular in P. glasbyi n. sp., with a single medial lobe only for P. plumosus ), by the shape of lower lip (wider than long for P. glasbyi n. sp., longer than wide for P. plumosus ), the type of notochaetae (absence of pinnate chaetae for P. glasbyi n. sp., present in P. plumosus ) and by the shape of uncini (presence of a main tooth above the main fang for P. glasbyi n. sp., but absent in P. plumosus ).

Polycirrus glasbyi n. sp. differs from P. nogueirai n. sp. by the first appearance of neuropodia (SG9–11 for P. glasbyi n. sp., SG14–16 for P. nogueirai n. sp.), by the shape of upper lip (triangular in P. glasbyi n. sp., whereas a single median elongated lobe present in P. nogueirai n. sp.), by the shape of lower lip (wider than long for P. glasbyi n. sp., rounded and as wide as long for P. nogueirai n. sp.), by the shape of notochaetae (with distal half enlarged for P. glasbyi n. sp., almost the same size for P. nogueirai n. sp.), by the presence of uncini with a subrostral process (absence in P. nogueirai n. sp.) and by a narrow gap between ventro-lateral pads (whereas a large gap present in P. nogueirai n. sp.).

Figures

FIGURE 8. Polycirrus glasbyi n. sp., paratype MNHN-IA-TYPE 2012 (A), additional material SMA-Arc-Poly-08 (B), holotype MNHN-IA-TYPE 2010 (C), paratype AM W.53116 (D), paratype MNHN_Arc_Poly_29 (E), additional material SMA- Arc_Poly_09 (F). A. Anterior end, ventral view; B. Anterior end, in Bittium reticulatum shell, antero-frontal view; Anterior end, lateral view; D. Entire specimen, lateral view; E. Notochaetae, SG4, 100x objective; F. Uncini, SG13, 40x objective. Abbreviations: Bt, buccal tentacle; Ll, lower lip; Ul, upper lip; Sp, subrostral process.

FIGURE 9. Polycirrus glasbyi n. sp., SEM, paratype AM W.53118. A. Anterior end, ventral view; B. Notopodia, SG5, ventral view; C. Notochaetae, SG5; D. Thoracic uncini.Abbreviations: Ll, lower lip; Ul, upper lip. Numbers refer to segments.