Thelepus recheri Lavesque, Pinsivy & Hutchings 2025, n. sp.

Thelepus recheri Lavesque, Pinsivy & Hutchings n. sp. zoobank.org:act: 6483B533-7FE5-4DF5-9896-22D6C3B5A664 Figures 5 and 6 Material examined. Holotype. MNHN-IA-2000-2102, North Atlantic Ocean, Saint-Pierre and Miquelon Archipelago, West of Saint-Pierre Island, SPM 32, 46.771292° N, 56.307388° W, 46 m depth, September 2023, complete, some parapodia used for molecular analysis. Paratypes. AM W.55318, North Atlantic Ocean, Saint-Pierre and Miquelon Archipelago, East of Saint-Pierre Island, SPM 4, 46.805247° N, 56.115607° W, 100 m depth, September 2023, complete, some parapodia used for molecular analysis, mounted for SEM. MNHN-IA-2000-2103, North Atlantic Ocean, Saint-Pierre and Miquelon Archipelago, SW of Saint-Pierre Island, SPM 30, 46.732683° N, 56.271452° W, 80 m depth, September 2023, incomplete, some parapodia used for molecular analysis. MNHN-IA-2000-2104, North Atlantic Ocean, Saint-Pierre and Miquelon Archipelago, SW of Saint-Pierre Island, SPM 30, 46.732683° N, 56.271452° W, 80 m depth, September 2023, complete, some parapodia used for molecular analysis. MNHN-IA-2000-2105, North Atlantic Ocean, Saint-Pierre and Miquelon Archipelago, East of Saint-Pierre Island, SPM 4, 46.805247° N, 56.115607° W, 100 m depth, September 2023, complete, gravid. Additional material. SMA-NL272, North Atlantic Ocean, Saint-Pierre and Miquelon Archipelago, SW of Saint-Pierre Island, SPM 30, 46.732683° N, 56.271452° W, 80 m depth, September 2023, some parapodia used for molecular analysis. Description (based on holotype and paratypes). Holotype complete (about 110 segments), 91.6 mm long, 3.3 mm wide. Largest paratype (MNHN-IA-2000-2105) 145 mm long and 4 mm wide. Prostomium at base of upper lip; numerous black eyespots in continuous dark band, with 3–4 irregular rows (Fig. 5B); buccal tentacles long, thick, deeply grooved (Figs 5A–D; 6A–B). Upper lip as wide as long, striated, thick, hood-like (Fig. 5D); lower lip thick, wider than long, striated, surrounded by ventral crescent-shaped lobe originating from SG1 (Fig. 5D). SG1 and SG2 short, visible laterally and dorsally (Fig. 5B). Two pairs of branchiae, on SG2–3, with 10–21 filaments on SG2 and 6–13 on SG3 (Figs 5B–C; 6A–B); filaments short, distally blunt, cylindrical, arising directly from body wall, with wide medial gap; branchial filaments arranged in two irregular rows (Fig. 5C). First pair of branchiae situated more laterally. Ventral surface of anterior segments strongly glandular, corrugated on anterior-most segments, ventral shields absent (Fig. 5D); thin mid-ventral stripe beginning from about SG29–30. Notopodia from SG3 to almost the end of the body, present on holotype from SG3 to SG97 (for about 110 segments), on paratype MNHN-IA-2000-2104 from SG3 to SG70 (for about 85 segments) and from SG3–84 (for about 90 segments) for paratype MNHN-IA-2000- 2105; notopodia short, roughly rectangular, distally rounded (Figs 5B–C; 6A–B); notochaetae emerging between lobes. Few falcate notochaetae in both rows, anterior row with about 10 twisted winged chaetae (Fig. 6C), posterior row with about eight narrowly-winged notochaetae (Fig. 6C); well-marked difference in length between rows (Fig. 6C). Neuropodia from SG5, as long fleshy ridges on anterior body, progressively shorter and more raised from midbody segments onwards (Figs 5E; 6D–E). Uncini with terminal dorsal button, short prow, much shorter than button, base curved; uncini longer than high (Fig. 6G). Crest of uncini with three rows of secondary teeth, basal row with 2–3 teeth, second row with 1–2 teeth, last row with irregularly sized teeth (Fig. 6F). Nephridial and genital papillae not seen. Pygidium with 5–6 globular papillae (Fig. 5E). Tube incrusted with gravels, foraminifera and shell fragments. Etymology. This species is dedicated to Jean Recher, a fishing captain from the days of great fishing on the banks of Newfoundland who wrote the book “Le Grand Métier” (“The Great Profession”). He probably dredged up many specimens of this new species. Type locality. North Atlantic Ocean, Saint-Pierre and Miquelon Archipelago. Distribution. Canadian region: Saint-Pierre and Miquelon Archipelago (this study), New Brunswick (Dewaard unpub; Carr et al. 2011 as T. cincinnatus in GenBank), Newfoundland and Labrador (Carr et al. 2011, as T. cincinnatus in GenBank) (Fig. 8; Table 2). Habitat. Between 46 and 100 m depth, pebbles with coralline crusts (rhodoliths), rocky substrate. Remarks. Only two species of Thelepus have been described from the NW Atlantic: T. abranchiatus (Hartman & Fauchald, 1971) and T. cincinnatus (Fabricius, 1780). The holotype of T. abranchiatus was re-examined by Hutchings & Glasby (1986). This last species differs mainly from Thelepus recheri n. sp. in the absence of branchiae, which are well developed in T. recheri n. sp. and in the number of notochaetae, which are present on 30 pairs of notopodia and 60% of the body length for T. abranchiatus and about 90 notopodia and until the end of the body in T. recheri n. sp. In addition, T. recheri n. sp. is a coastal species that lives at depths of between 50 and 100 m, while T. abranchiatus is a deep-water species sampled at 2022 m (Hutchings & Glasby 1986). Thelepus recheri n. sp. has probably been confused with the so-called cosmopolitan species T. cincinnatus, as for example in Carr et al. (2011) (Fig. 8). Indeed, this last species has been described from western Greenland which is only separated from SPM by the Labrador Sea and is largely reported in the Canadian region. Recently, Nogueira (2019) redescribed T. cincinnatus based on syntypes from the type locality (= “Torell’ topotypes ”). Based on morphological characters, the two species can easily be distinguished from each other. The branchiae of T. recheri n. sp. are separated by a wide medial gap which is inconspicuous for T. c incinnatus. The mid-ventral groove begins from SG10 for T. cincinnatus and from about SG30 for T. recheri n. sp. The notopodia of T. recheri n. sp. are present almost until the end of the body while they terminate far from the posterior end for T. cincinnatus. In the Northern hemisphere, another species has two pairs of branchiae, the presence of eyespots and notopodia until the end of the body: T. parapari Jirkov 2018, described from the Mediterranean Sea. However, T. recheri n. sp. differs by the presence of black eyespots instead of red ones (which are rarely present), by the higher number of branchial filaments (up to 21 filaments for the first branchiae and up to 17 for the second ones for T. recheri n. sp., instead of 11 and 8 filaments respectively for T. parapari), and by the shape of the pygidium which presents 5–6 globular papillae for T. recheri n. sp. and which is crenulated for T. parapari. The notochaetae of T. parapari are usually in one row with mixed short and long chaetae while there are always two rows for T. recheri n. sp. with well-marked difference in length between rows. The posterior uncini of T. parapari have only one row of tooth/teeth above the main fang (“uncini have only one tooth in profile”) while there are always two rows above the main fang for T. recheri n. sp. Finally, the two species are found in two very different habitats with T. recheri n. sp. found up to 100 m depth in a sub-Arctic region and T. parapari present in the Mediterranean Sea up to 15 m depth. The molecular results allow us to confirm the presence of T. recheri n. sp. in several localities in Canada. The intraspecific distances (K2P) between the SPM specimens and the Canadian specimens observed are 0% for both COI and 16S. The 16S sequences of T. recheri n. sp. are very different (K2P: 7.6%) from a sequence of T. cincinnatus from Trondheim in Norway (GenBank accession number DQ779636, Fig. 7) (Rousset et al. 2007), but once again we have no certainty that this has been correctly identified. The type species of the genus, Thelepus cincinnatus (Fabricius, 1780), has long been considered as a cosmopolitan species with a worldwide distribution. The democratisation of molecular tools has led to major advances in our understanding of geographical distributions and has highlighted that many cosmopolitan species are actually complexes of cryptic or pseudo-cryptic species (Nygren et al. 2018; Hutchings & Lavesque 2020; Lavesque et al. 2021b). It is now accepted that such a wide distribution and variety of habitats, as for T. cincinnatus, is unlikely. Recently, Jirkov redescribed T. cincinnatus but while he used almost 2000 specimens from more than 100 stations, none of these stations were from the type locality, but instead covered a wide range of depths (2 to 2000 m), from the Arctic to the Mediterranean (Jirkov, 2018). To confirm his identification, he compared his specimens with Pettibone’s description of topotypes (Pettibone 1954). However, Pettibone used a large number of specimens for her description, with animals collected from both the Beaufort Sea, the east and west coasts of the USA and the type locality (eastern Greenland), and no topotype was formally established as a name-bearing type. However, with such a wide geographical distribution, it is possible that she was dealing with several different species. Finally, in 2019, Nogueira was able to examine specimens of T. cincinnatus stored in the Naturhistoriska Riksmuseet (Swedish Museum of Natural History) in Stockholm, Sweden. Three specimens (NRM 84944) “which apparently were intended to be designated as syntypes, as the lot is labelled as ‘Type 1270’ in the museum’s old catalogue, but that never happened” (Nogueira 2019). These specimens were collected by O. Torell in 1859, almost 80 years after the original description (Fabricius 1780), at the same locality as the worms studied by Fabricius (Nogueira, 2019). These “Torell’ topotypes ” and their precise description, permitted us to confirm that specimens from SPM belong to a different, undescribed, species: Thelepus recheri n. sp.

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