Paucibranchia glemareci, Pinsivy & Lavesque & Daffe & Daramy & Hutchings, 2025

Pinsivy, Lucas, Lavesque, Nicolas, Daffe, Guillemine, Daramy, Flore & Hutchings, Pat, 2025, Paucibranchia glemareci sp. nov. (Annelida, Eunicidae), a new species from the French Atlantic continental shelf, ZooKeys 1232, pp. 187-203 : 187-203

publication ID	https://doi.org/10.3897/zookeys.1232.143944
publication LSID	lsid:zoobank.org:pub:0A9637CB-31D1-4D68-8B9B-DDFBB6319C71
DOI	https://doi.org/10.5281/zenodo.15047020
persistent identifier	https://treatment.plazi.org/id/4EAC680D-208B-56DA-8ED5-AA1DC8F71899
treatment provided by	ZooKeys by Pensoft
scientific name	Paucibranchia glemareci
status	sp. nov.

Treatment

Paucibranchia glemareci sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4

Material examined.

Holotype. France – Bay of Biscay • “Grande Vasière”; 46.800, -3.750; depth 128 m; Sep. 2019; APPEAL ATL 19-2 Campaign; station FLLD 2 ; Hamon grab; MNHN -IA 2000-2112 GoogleMaps Paratypes. France – Bay of Biscay • 3 specimens; same collection data as for the holotype; MNHN -IA 2000-2113 and MNHN -IA 2000-2114 , AM W.55320 GoogleMaps • 1 spec.; “ Grande Vasière ”; 47.116, -3.910; depth 116 m; Sep. 2019; APPEAL ATL 19-2 Campaign; stn FLLC 3; Hamon grab; MNHN -IA 2000-2115 GoogleMaps • 1 spec.; “ Grande Vasière ”; 46.940, -3.480; depth 109 m; Sep. 2019; APPEAL ATL 19-2 Campaign; stn FLLBB 1; Hamon grab; MNHN -IA 2000-2116 GoogleMaps • 1 spec.; “ Grande Vasière ”; 47.150, -3.587; depth 101 m; May 2019; APPEAL ATL 19-1 Campaign; stn 5880; Rallier du Baty dredge; MNHN -IA 2000-2117 GoogleMaps • 1 spec. (mounted for SEM); same data as for MNHN -IA 2000-2117; AM W.55323 GoogleMaps .

Additional material for molecular analyses.

Paucibranchia glemareci sp. nov. France – Bay of Biscay • 1 spec.; “ Grande Vasière ”; 47.514, -4.540; depth 112 m; Oct. 2022; EVHOE 2022 Campaign; stn A 1470; Rallier du Baty dredge; GenBank no: PV 021094 (COI); SMA -NL 298 GoogleMaps Paucibranchia bellii . France – Brittany • 1 spec.; Morlaix Bay, Pierre Noire GoogleMaps ; 48.708, -3.866; depth 17 m; Feb. 2023; Céline Houbin leg.; Van Veen grab; GenBank no: PV 019095 (COI); SMA -NL 194 • 2 specs; Brignogan GoogleMaps ; 48.673, -4.321; Intertidal; Mar. 2023; Jacques Grall leg.; Hand corer; GenBank no: PV 019094, PV 019092 (COI); SMA -NL 192 and SMA -NL 183 • 1 spec.; Brest, “du Château” harbour GoogleMaps ; 48.378, -4.488; depth 5 m; Jul. 2022; Vincent Le Garrec leg.; Day grab; GenBank no: PV 019093 (COI); SMA -NL 185 .

Diagnosis.

Prostomium anteriorly rounded with ventral sulcus. Five prostomial appendages arranged in an arc on posterior margin of prostomium. Eyes present, round and dark. Maxillary formula: 1 + 1, 8 + 9 (8), 9 + 0, 5 (6) + 10, 1 + 1. Branchiae pectinate, present from chaetiger 14–16 to 31–33 with 8–13 long filaments. Dorsal cirri always well developed, slightly longer but thinner in postbranchial chaetigers. Ventral cirri shorter than dorsal cirri, bluntly triangular in pre-branchial region, becoming bluntly conical and thinner through the body. Postchaetal lobes well developed in anterior part of body, becoming inconspicuous from about chaetiger 45 onwards. Three or four light brown aciculae in prebranchial chaetigers, decreasing to two in anterior part of branchial region and to one thereafter. Subacicular hooks light brown, bidentate, commencing from chaetiger 33–37 and present in all following chaetigers; most often one per chaetiger but sometimes two in posterior part of body. Compound chaetae all bidentate falcigers, with two sizes of blades, short ones about 50 µm, long ones about 90 µm. One type of pectinate chaetae identified: narrow, isodont with 2–5 long and slender internal teeth. Posterior pectinate chaetae, if different, unknown. Pygidium unknown.

Description

(based on holotype, with variation in parentheses for paratypes). Specimens fixed in alcohol whitish, specimens fixed in formalin pinkish with reddish spots on prostomium, ventrum, parapodia, dorsal cirri, and lateral parts of dorsum (Fig. 2 B, C View Figure 2 ). All specimens incomplete, holotype with 60 chaetigers (longest paratype with about 90 chaetigers), about 26 mm (13.3–47.5 mm) long, 1.9 mm (1.0– 2.5 mm) wide at chaetiger 10, including parapodia. Body round in cross section anteriorly (about chaetiger 7–8), dorsoventrally flattened thereafter.

Prostomium anteriorly rounded (slightly conical), without dorsal median sulcus, ventral sulcus deep (Figs 2 A – D View Figure 2 , 4 A, B View Figure 4 ). Palps and antennae arranged in an arc on posterior margin of prostomium. Median antenna isolated by gap from lateral antennae and palps. Median antenna longer than lateral ones, lateral antennae longer than palps, antennae much longer and palps slightly longer (same size) than prostomium (Figs 2 B View Figure 2 , 4 A View Figure 4 ). Median antenna reaching chaetiger 3 (2), lateral antennae end of chaetiger 1 (end of second peristomial ring) and palps second peristomial ring (end of first peristomial ring) (Figs 2 B View Figure 2 , 4 A View Figure 4 ). Ceratostyles and palpostyles slender and tapering, with indistinct cylindrical articulations. Ceratophores and palpophores indistinct. Eyes present, one pair, rounded, black, situated at posterior base of palps and lateral to lateral antennae (Fig. 2 B View Figure 2 ). Separation between both peristomial rings distinct on all sides. First peristomial ring as long as second one dorsally (1 ½ × as long as second one), twice as long laterally (Figs 2 B View Figure 2 , 4 A View Figure 4 ). Anterior dorsal margin of first peristomial ring forming convoluting collar on holotype and most paratypes (Fig. 2 B View Figure 2 ). Some small specimens (non-type), less than 1 mm wide, lacking palps.

Maxillary formula as follows: MF = 1 + 1, 8 + 9 (8), 9 + 0, 5 (6) + 10, 1 + 1, MVI absent (Fig. 3 E View Figure 3 ). Maxillary carrier approximately 2 × shorter than MI, rectangular anteriorly, triangular posteriorly, with a pair of rounded wings situated at posterolateral margins. MI forceps-like, without attachment lamellae, with falcal arch developed, rounded; with outer edge of base straight and with curvature in basal inner edge where base of maxillae II is supported. Closing system approximately 5 × shorter than MI. MII without attachment lamella but with small basal ligament, teeth triangular, distributed on half of plate length. MIII, single, longer than left MIV, slightly curved, with equal-sized triangular teeth, without attachment lamella but with small basal ligament. Left MIV short (less than half length of right MIV), attachment lamella dark, 2 × shorter than corresponding MIV, subtriangular. Right MIV long, with teeth triangular, decreasing in size posteriorly; attachment lamella oval, 3 × shorter than corresponding MIV, dark. MV, paired, longer than high, whitish (Fig. 3 E View Figure 3 ). Mandibles light brown, with concentric stripes; longer than MI; cutting plates whitish (Fig. 3 F View Figure 3 ).

First three parapodia smallest; most developed from chaetiger 4 to end of branchial chaetigers, following ones becoming gradually smaller (Fig. 3 A – D View Figure 3 ). Prechaetal lobes as transverse fold in all chaetigers. Postchaetal lobes well developed until end of branchial chaetigers, bluntly triangular in first 9–10 chaetigers, becoming conical, longer and thinner through branchial region, then decreasing in size, becoming inconspicuous from about chaetiger 45. Dorsal cirri conical, tapering, becoming slender and longer from first chaetiger to end of branchial region, then filiform until end of body. Dorsal cirri slightly longer in post-branchial region than in pre-branchial chaetigers. Ventral cirri shorter than dorsal cirri, bluntly triangular in pre-branchial region, becoming bluntly conical and thinner throughout body (Fig. 3 A – D View Figure 3 ).

Branchiae pectinate, commencing from chaetiger 16 (14–15) continuing for a limited number of segments, until chaetiger 32 (31–33); with 8–13 long filaments; branchial filament about 1.5 × longer than dorsal cirri where best developed (Figs 2 C View Figure 2 , 3 B View Figure 3 ). Smaller specimens (non-type) have branchiae starting earlier and less numerous (from chaetiger 11 to 20 for a specimen 0.8 mm wide).

Aciculae light brown with paler blunt tips, three or four aciculae on pre-branchial chaetigers, two on anterior part of branchial region, and one from mid part of branchial region and following chaetigers; some posterior chaetigers with two aciculae. Supra-acicular chaetae with limbate capillaries and pectinates; capillaries present from first chaetiger to posterior ones, numbering up to 15 in anterior chaetigers and up to five in posteriormost chaetigers (Fig. 4 C, D View Figure 4 ). One type of pectinate chaetae identified: narrow, isodont with 2–5 long and slender internal teeth; inner teeth with terminal filaments; outer teeth longer, but of different length (Fig. 4 E, F View Figure 4 ), anterior body with two or three pectinate chaetae by parapodium, mid-body chaetigers with one chaeta, not seen posteriorly (but longest paratype with most of posterior chaetae broken). Subacicular chaetae including compound falcigers and subacicular hooks, compound spinigers absent (Fig. 4 C, D View Figure 4 ). Compound falcigers bidentate, with two sizes of blades, short ones about 50 µm, long ones about 90 µm, commencing from first chaetiger to posterior part, with more than 30 chaetae within parapodium in anterior part, with about seven chaetae in mid-body and four or five on last chaetigers (Fig. 4 C, D View Figure 4 ). Subacicular hooks ( SAH) light brown, bidentate, commencing from chaetiger 35 (33–37) and present in all chaetigers thereafter, ventral to bundle of falcigers, generally one per parapodium; few posterior chaetigers with two hooks (Fig. 4 D View Figure 4 ). Smaller specimens (non-type) have SAH starting earlier (at 19 th chaetiger for a specimen of 0.6 mm wide and at 29 th for a specimen 0.8 mm wide).

Pygidium unknown.

Etymology.

This species is named after Michel Glemarec for his major contribution to the ecology of the Grande Vasière and the taxonomy of polychaetes.

Type locality.

Northeastern Atlantic Ocean, Bay of Biscay, “Grande Vasière”, Station FLLD 2 (46.800, -3.750, 128 m depth).

Distribution.

Known from the “ Grande Vasière ” area.

Habitat.

Fine sands to muddy sands, between 100 and 130 m depth.

Remarks.

Paucibranchia glemareci sp. nov. is easily distinguished from other species described from Europe by the presence of compound falcigers and the absence of compound spinigers. It is, however, very close to P. adenensis ( Gravier, 1900) , described from Yemen and (questionably) later reported from the Mediterranean Sea ( Katsiaras et al. 2014; Katsiaras 2021; Rousou et al. 2023; Langeneck et al. 2024). These two species share the presence of rounded eyes, only falcigerous compound chaetae, same branchial distribution and similar looking bidentate sub-acicular hooks. They can however be separated based on morphological characters. According to the redescription of P. adenensis by Molina-Acevedo (2018), P. glemareci sp. nov. differs by its maxillary formula (1 + 1, 8 + 9 (8), 9 + 0, 5 (6) + 10, 1 + 1) versus (1 + 1, 7 (8) + 7 (8), 6 (7) + 0, 4 (5) + 7 (8-9), 1 + 1) for P. adenensis , the number of aciculae on prebranchial chaetigers (up to four for P. glemareci sp. nov. versus up to two for P. adenensis ) and shorter blades on anterior compound falcigers (50 and 90 µm for P. glemareci sp. nov. versus 90 and 105 µm for P. adenensis ). Moreover, both species appear to have a different colouration after fixation; P. glemareci sp. nov. presents reddish spots on most specimens, but never brown colouration as observed on some non-type specimens of P. adenensis by Molina-Acevedo (2018).

Worldwide, P. glemareci sp. nov. shares the absence of compound spinigers with P. conferta ( Moore, 1911) , P. gathofi Molina-Acevedo, 2018 , P. gemmata ( Mohammad, 1973) , P. miroi Molina-Acevedo, 2018 , P. patriciae Molina-Acevedo, 2018 , P. purcellana ( Willey, 1904) , P. triantennata Kim, Soh & Jeong, 2022 and with an undescribed species ( Paucibranchia sp. 2 of Molina-Acevedo 2018). However, it differs from P. conferta , P. gemmata , P. miroi , P. patriciae , P. purcellana , and P. sp. 2 by the chaetiger on which the branchiae start (chaetiger 14–16 for P. glemareci sp. nov. versus chaetiger 22 for P. gemmata , chaetiger 10–12 for P. triantennata and chaetiger 7 or 8 for the other five species) and from P. gathofi by the chaetiger where subacicular hooks start (chaetiger 33–37 for P. glemareci sp. nov. versus chaetiger 17–30 for P. gathofi ).

Paucibranchia glemareci sp. nov. may have been mistaken in the past for P. bellii (as Marphysa bellii ), the only name for specimens with pectinate branchiae restricted to the anterior part of the body in the early literature (e. g. Fauvel 1923). Thus, old records of P. bellii from offshore area in the Bay of Biscay should be regarded as doubtful.