taxonID	type	description	language	source
03EA55484961FFFDF1ADEE9DFC16FBB3.taxon	type_taxon	Type species. Thelepus cincinnatus (Fabricius, 1780) by original designation.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	description	zoobank. org: act: 6 ACD 11 A 8 - 7476 - 47 AF-A 5 B 2 - 537160 E 49627 (Figures 2 – 3)	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	materials_examined	Type material: Holotype: MNHN IA 2000 - 2127, North Atlantic Ocean, West Africa, Mauritania, Banc d’Arguin National Park, Arkeiss, 20.1302 ° N, 16.2593 ° W, 2 m, 31 st May 2024; fixed and preserved in 80 % ethanol. Paratypes: MNHN IA 2000 - 2128, gravid, complete; MNHN IA 2000 - 2130, MNHN IA 2000 - 2129 and AM W. 55325 (fixed and preserved as holotype) and AM W. 55326 (mounted for SEM) with some parapodia used for molecular analysis; sampling data as holotype, one specimen for each paratype.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	description	Description. Holotype complete (about 110 segments), 114.9 mm long, 6.1 mm wide. Prostomium at base of upper lip; small eyespots in thin and continuous dark band, with 1 – 2 irregular rows (Fig. 2 D); buccal tentacles dark when fixed, long, thick, deeply grooved (Figs 2 A – C; 3 A). Upper lip as wide as long, striated, thick, hood-like (Fig. 2 C); lower lip striated, crescent-shaped (Fig. 2 C); pharyngeal organ visible on some specimens. Segments 1 – 2 short, visible laterally and dorsally. Three pairs of branchiae, on segments 2 – 4, originating from large glandular cushion-like structures; first pair lateral, with a cushion structure below notopodia; first and third pairs with very narrow, almost inconspicuous medial gap, more developed between filaments of second pair; branchia with many twisted short, distally blunt, cylindrical filaments (≈ 70 in first pair; 35 in second pair; 15 in third one) (Figs 2 A – B; 3 A). Ventral surface of anterior segments strongly glandular, corrugated on anterior-most segments; ventral shields absent (Fig. 3 C); thin mid-ventral stripe from about segment 18 to almost end of body. Notopodia from segment 3, on 20 – 36 % of entire body length (holotype with 31 pairs of notopodia, for about 110 segments); notopodia large, roughly rectangular, distally rounded (Figs 2 A – B; 3 A – C); notochaetae emerging between lobes, in two rows: anterior with ≈ 10 – 20 twisted winged chaetae, posterior with ≈ 10 – 20 narrowly-winged chaetae; difference in length between rows well-marked (Figs 2 G, 3 B – C). Neuropodia from segment 5, as long fleshy ridges on anterior body, progressively shorter and more raised from mid-body to become rounded papillae on segments close to pygidium (Figs 2 A – B; 3 D). Thoracic uncini with terminal dorsal button (Fig. 2 H), abdominal uncini with sub-terminal dorsal button and short pointed prow (Fig. 2 I); all uncini longer than high, with base curved. Crest of thoracic uncini with two rows of secondary teeth above main fang, basal row with two teeth, upper row with minute teeth (Fig. 3 E); crest of abdominal uncini with two rows of secondary teeth above main fang, basal row with two teeth, second row with irregularly sized teeth, slightly larger than those of upper row of thoracic uncini (Fig. 3 F). Nephridial (segment 5) and genital (segment 6 – 7) papillae short, between noto- and neuropodia (Fig. 2 A). Pygidium with 5 – 6 globular papillae (Fig. 2 F). Tube incrusted with gravel, shell fragments, small fauna (e. g. serpulids, ascidians, bryozoans) (Fig. 2 E).	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	etymology	Etymology. Named after the Banc d’Arguin National Park, where the new species was collected.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	materials_examined	Type locality. North Atlantic Ocean, West Africa, Mauritania, Banc d’Arguin National Park, Arkeiss.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	distribution	Distribution. Only known from the type locality.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	biology_ecology	Habitat. Rocky substrate, 2 m depth. Ecology. The specimens occur in association with diverse fauna, both on their tubes (including serpulids, ascidians, and bryozoans) and also within the tubes, with the commensal polynoid L. hupferi being found inside the tubes of two specimens (Fig. 2 E).	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA55484961FFFEF1ADE9C1FCD1FB2A.taxon	discussion	Remarks. Thelepus arguinensis sp. nov. differs from the Namibian T. pequenianus Augener, 1918 in several morphological characters, particularly the branchiae and uncini. Thelepus arguinensis sp. nov., bears> 70 filaments in the first pair of branchiae (about 20 in T. pequenianus), has branchiae arising from large glandular cushion-like structures (glandular base poorly developed in T. pequenianus), and the medial gap is almost inconspicuous in first and third branchial pairs and more developed in the second (very small medial between first pair, increasing slightly in second and third pairs in T. pequenianus). Thoracic uncini in T. arguinensis sp. nov. lack prow which is present in thoracic and abdominal uncini of T. pequenianus. Moreover, notopodia are present on 30 – 36 % of the segments of T. arguinensis sp. nov., while they are present on 64 % of the segments of T. pequenianus. This last species is also characterised by the presence of large gonopores from segment 8 to segment 13 which are absent for T. arguinensis sp. nov. Finally, T. arguinensis sp. nov. is currently known only from Mauritania, in the northern hemisphere, while T. pequenianus occurs ≈ 7000 km away, in the southern hemisphere (South Africa, Namibia). Although both species are present on the same coastline, they live in very distinct biogeographical regions. Three 16 S and two COI sequences were successfully obtained (Table 1). The intraspecific distances between the specimens of T. arguinensis sp. nov. range from 0 – 1.2 ± 1.13 % for 16 S gene and were 1 % for COI (Figs 4; 5). Phylogenetic analyses confirm the separation of T. arguinensis sp. nov. from all congeners with available sequences: for 16 S, its closest relative is T. verrilli (Treadwell, 1911) (K 2 P distance = 27.5 ± 1.14 %) (Fig. 4), while for COI is T. crispus Johnson, 1901 (K 2 P distance = 24.5 ± 0.2 %) (Fig. 5).	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA5548496DFFF1F1ADE929FC59FB4F.taxon	type_taxon	Type species. Aphrodita clava Montagu, 1808 by original designation.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA5548496DFFF3F1ADE85DFBBAFA16.taxon	description	(Figure 6)	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA5548496DFFF3F1ADE85DFBBAFA16.taxon	materials_examined	Type material. Lepidonotus hupferi Augener, 1918 from W Africa, Ambrizette (Angola), 12 m, collector A. Hupfer, determinator Augener (1918): 7 syntypes (ZMH- 530, ZMH- 531, ZMH- 532 and ZMH- 590), at Zoologisches Museum Hamburg, Germany.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA5548496DFFF3F1ADE85DFBBAFA16.taxon	description	Description (based on both specimens). MNHN-IA- 2017 - 2207 complete specimen, 25 mm long, 3.9 mm wide, for 26 segments (including tentacular segment); SMA _ NL 291 complete specimen, 15.4 mm long and 2.1 mm wide for 26 segments (including tentacular segment). Living colouration unknown; in ethanol, pale yellow with middorsal brownish to dark green bands on anterior segments (Fig. 6 A); elytra with similar but denser pigmentation, overlapped margin not coloured. Prostomium hexagonal (Fig. 6 A), withdrawn into following segment (SG 2), posterior margin not visible; without cephalic peaks. Median antenna, with ceratophore at anterior notch, distinct, style smooth, slightly inflated subdistally. Lateral antennae terminal, ceratophores fused to prostomium, styles smooth, subulate, abruptly tapering into thin tips, shorter (~ 0.75 x) than median style. Palps stout, minutely papillated, subulate, abruptly tapering into thin tips, about as long as lateral antennae. Two pairs of eyes: anterior dorsolateral at widest part of prostomium, posterior pair dorsal to anterior pair, near posterior margin. Tentaculophores lateral to prostomium, with few chaetae and one pair of tentacular cirri, styles smooth, abruptly tapering into thin tips; dorsal tentacular cirri slightly inflated subdistally, longer (~ 1.25 x) than ventral cirri, as long as median antenna; ventral cirri as long as palps. Segment 2 with first pair of elytra, sub-biramous parapodia, and long ventral buccal cirri, abruptly tapering into thin tips. Twelve pairs of elytra; anteriormost pairs missing, subsequent elytra not completely covering dorsum. Elytra large, oval, soft, strongly folded; surface with small, round to slightly elongated microtubercles (Fig. 6 B) with warty to multifid, crown-like tips; macrotubercles absent; sac-like structures — possibly protozoans — on many elytra of larger specimen (Fig. 6 C); elytral margins with fringing papillae on exposed lateral edge. Dorsal cirri with large, triangular to cylindrical cirrophores; styles smooth, abruptly tapering into thin tips, reaching notochaetal tips at mid body. Ventral cirri with styles smooth, short, abruptly tapering into thin tips, shorter than neuropodia. Dorsal tubercles inconspicuous. Parapodia sub-biramous. Noto- and neuropodia with elongate acicular lobes; noto- and neuroacicula penetrating epidermis (tips mostly broken). Notopodia small, conical. Neuropodia with subtriangular prechaetal and postchaetal acicular lobes of similar size. Notochaetae moderate in number (≈ 25), short to long, slightly curved, slender with multiple rows of small spines and tapering capillary tips (Fig. 6 D); mostly covered by inorganic matter. Neurochaetae moderate in number (≈ 25), long, stouter, falcate, with ≈ 10 rows of distal spines; upper row with nearly twice longer spines and bidentate tips (Fig. 6 E), upper neurochaetae of segments 2 and 3 with unidentate tips. Nephridial papillae from segment 7 onwards, bulbous, small.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA5548496DFFF3F1ADE85DFBBAFA16.taxon	materials_examined	Type locality. Coastal waters of Ghana, western Africa.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA5548496DFFF3F1ADE85DFBBAFA16.taxon	distribution	Distribution. Eastern Atlantic: Mauritania (present study) to Cape Verde. Western Pacific: New Caledonia and Japan. Eastern Pacific: Mexico to Ecuador. Depth range: intertidal to 30 m. Most of these records appear to be doubtful and this species is probably restricted to West Africa.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
03EA5548496DFFF3F1ADE85DFBBAFA16.taxon	discussion	Remarks: Lepidonotus currently comprises 75 species (Read & Fauchald 2025 b), 35 of which were originally described over two centuries ago, with descriptions varying in detail, making comparisons with modern descriptions difficult. Species with fringed elytra and bidentate neurochaetae include at least 14 taxa. Among them, L. hupferi is distinguished by the absence of macrotubercles and presence of small non-carinate microtubercles with multifid tips. The sac-like structure observed on some elytra of the larger specimen likely represent encrusting organisms (probably epibiotic protozoans) rather than inherent morphological traits, since they were not seen on all elytra and are absent on the smallest specimen, although both specimens were adults. It seems that some confusion arose a long time ago. Day (1967, p. 37) stated, in the list of records from southern Africa, that L. hupferi was synonymous with L. tenuisetosus. However, he did not officially present it in the section devoted to the synonymy of L. tenuisetosus (Day 1967, p. 82), which led to a non-existent synonymy (never mentioned in WORMS either). We believe that these are distinct species, as L. hupferi clearly has bidentate neurochaetae, whereas L. tenuisetosus, as indicated by Day (1967), has slightly bidentate or unidentate neurochaetae. This study provides the first DNA sequences — two 16 S for SMA _ NL 291 (PX 560833) and for MNHN-IA- 2017 - 2207 (PX 560834), and one COI for SMA _ NL 291 (PX 434398) — for L. hupferi.	en	Lavesque, Nicolas, Bonifácio, Paulo, Gouillieux, Benoit, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat (2026): A new species of Thelepus (Annelida, Terebelliformia) from Banc d’Arguin, Mauritania, and its associated scaleworm Lepidonotus hupferi Augener, 1918 (Annelida, Polynoidae). Zootaxa 5748 (1): 73-88, DOI: 10.11646/zootaxa.5748.1.3, URL: https://doi.org/10.11646/zootaxa.5748.1.3
