Marphysa gili Martin and Romano, 2025

Martin, Daniel, Chaibi, Marwa, Lavesque, Nicolas, Daffe, Guillemine, Daramy, Flore, Hutchings, Pat, Jourde, Jérôme & Romano, Chiara, 2025, Integrative taxonomy reveals further hidden diversity of Marphysa (Polychaeta: Eunicidae) in European Atlantic and Mediterranean waters, Zoological Journal of the Linnean Society 204 (3) : -

Marphysa gili Martin and Romano , sp. nov.

( Figs 12–15)

LSID urn:lsid:zoobank.org:act:AA1775A1-6C41-40B1-AC54-FB9091A0CD99 .

Material examined: Holotype: CEAB.AP.1000A, February 2020, Gulf of Fos , France, approximate location 43°25′N 4°56′E, fixed in 4% formalin seawater solution and preserved in 70% ethanol, one specimen entire, dissected to extract jaws, collected by Creocean team . Paratypes: MNHNC MB29 :000453 and MB29 :000454, October 2023, Gulf of Fos , France, approximate location 43°24′54′′N 4°50′42′′E, fixed in 4% formalin seawater solution and preserved in 70% ethanol, one specimen entire, dissected to extract jaws, collected by Creocean team . CEAB. AP.1000B, November 2019, Port la Nouvelle , France, approximate location 43°0′29′′N 3° 4′35′′E, fixed in 4% formalin seawater solution and preserved in 70% ethanol, one specimen (anterior fragment), collected by Creocean team .

Description: Based on holotype. Body 49 mm long, 6.5 mm wide, width uniform along body, with 128 chaetigers ( Table 2), rounded in cross section anteriorly, tapering and dorsoventrally flattened posteriorly, lacking most posterior segments ( Fig. 12A–F). Prostomium dorsoventrally flattened, with anterior end elevated, bilobate, with a conspicuous median sulcus ( Fig. 12A, D). One median and two lateral antennae, thin, distally tapering, folding back to middle of chaetiger 2; two palps, similar in shape to antennae, folding back until beginning of chaetiger 2 ( Fig. 12A–D). One pair of dark-brown reniform eyes, placed laterally to ceratophores of lateral antennae ( Fig. 12D). Calcareous cutting plates, 36 µm long and 67 µm wide, 1/4 shorter than sclerotized matrix, overall thick, with thin translucent borders, broadly B-shaped ( Fig. 13A, C); sclerotized matrix c. six times shorter than mandible carriers, D-shaped, distally straight, with smooth upper margin and growth ring-like marks seen though translucent calcareous cutting plates; left carrier with swollen distal end ( Fig. 13A, B). MxI c. three times as long as carrier, brown, with white, translucent tips; MxII c. four-fifths of MxI; MxIII arched, with anteriormost teeth more lateral than posteriormost ones, partly ventral to MxII, brownish, with teeth border whitish; attachment lamella of MxIII very small, straight, elongated, slightly sclerotized; left MxIV as wide as long, D-shaped; right MxIV four times longer than wider, arched; both Mx IV with concave side and posterior part of convex side brownish, anterior part of convex side and teeth border whitish; attachment lamellae of MxIV roughly C-shaped, ventral to Mx, right one with lower arm (pointed) c. three times shorter than right arm (rounded), left one with both arms rounded, similar in length; MxV roughly square, whitish; maxillary formula: I = 1 + 1, II = 4 + 4, III = 7 + 0, IV = 4 + 6, V = 1 + 1, VI absent ( Fig. 13D–F). Notopodial cirri triangular, tapering; longer (anterior), shorter (median and posterior), and longer (posteriormost) than chaetal lobes ( Fig. 14A–C). Branchial filaments starting at chaetiger 19, with a maximum of three filaments from chaetigers 50–73; longest filaments 4.8 times longer than notopodial cirri and 5.9 times longer than branchial stem ( Fig. 14B, C). Ventral cirri triangular, with rounded tips, with inflated bases from chaetiger 6 to posterior body end, as long as notopodial cirri in anteriormost chaetigers, one-third at midbody ( Fig. 13A–C). Notopodial aciculae inconspicuous. Neuropodial aciculae, brownish, with golden tips, up to three per parapodia, with blunt tips non-protruding from acicular lobe ( Fig. 14A–C). Chaetae in two distinct bundles: supracicular with limbates and pectinates at anterior edge, and subacicular with compound spinigers and one golden subacicular hook, with guards covering tip, bidentate, with short, rounded, upwards directed teeth separated by a narrow angle ( Fig. 15D, E), starting at chaetiger 40, present on all following chaetigers. Pectinate chaetae of four types, present in all chaetigers, except 1–4. Type 1 present from anterior parapodia, flat to little curved, isodont, slightly asymmetrical, with external teeth similar in length, with c. 25 narrow teeth about 4.3 µm long, similar in length on different chaetae, with pointed tips ( Fig. 15A). Type 2 thick, flat to little curved, isodont, slightly asymmetrical with short external teeth slightly differing in length, with 25 narrow teeth about 5 µm long, coarse, with pointed tips, slightly varying in length on different chaetae ( Fig. 15B, specimen from Port la Nouvelle). Type 3 thick, isodont, slightly asymmetrical, with external teeth of same length as internal ones, with 10–14 short coarse teeth with pointed tips ( Fig. 15B, specimen from Port la Nouvelle). Type 4 thick, non–curved, anodont, asymmetrical, with 7–11 coarse teeth with pointed tips, 18–25 µm long, c. eight times longer than wider ( Fig. 15C). Pygidium with four anal cirri, dorsal ones c. seven times longer than ventral.

Variation: Specimens MNHNC MB29:000453 and MB29:000454 from Gulf of Fos fragmented in several parts, anterior one longest (2.4–5 cm long, 0.5–0.7 cm wide, for 72–83 chaetigers); branchiae starting at chaetigers 16 and 25, subacicular hooks starting at chaetigers 37 and 42; nondissected, jaws not seen. Specimen from Port La Nouvelle ripe female with intra-coelomic oocytes (195–210 µm in diameter, Fig. 14F), body c. 40 mm long, 7.5 mm wide, with 67 segments, lacking middle and posterior segments ( Table 2). Antennae folding back to middle of chaetiger 4 ( Fig. 12G, I; Table 2). Maxillary formula with MxIII 6 + 0 and MxIII 3 + 6 ( Fig. 13G; Table 2). Branchiae starting at chaetiger 24, with 2(1) filaments to chaetiger 44, then three ( Fig. 13E) to chaetigers 67 (left side) or 64 (right side) ( Fig. 13H, 14E); last three right-side segments with four filaments, longest filament 5.7 times longer than notopodial cirri ( Fig. 14F; Table 2). Aciculae 3–4 up to chaetiger 40, then 2–3 till last available body segment. Subacicular hooks starting from chaetiger 40–45 ( Table 2), present to last available body segment, bidentate, with two guards, sometimes one broken ( Fig. 15F).

Remarks: The specimens from southern France belong to the species of the ‘ sanguinea ’ group having bidentate subacicular hooks ( Quatrefages 1866, Hansen 1882, Webster 1884, Gravier 1907, Treadwell 1917, Hutchings and Karageorgopoulos 2003, Liu, Hutchings and Sun 2017, Kara et al., 2020, Lavesque et al., 2020, Molina-Acevedo and Idris 2020, Abdulla et al., 2024). They differ from Marphysa birgeri Molina-Acevedo and Idris, 2020 , M. haemasona Quatrefages, 1866 , and M. multipectinata Liu et al., 2017 , which have bidentate subacicular hooks from chaetigers 25/27, 60, and 20, respectively (40/ 45 in M. gili sp. nov.). Marphysa birgeri , which was described from the Adriatic Sea, resembles M.gili sp. nov. in having the teeth of bidentate subacicular hooks with blunt tips and upwards directed, but differs in having longer teeth (distal smaller than proximal) separated by a wide angle and occasionally bearing a second, unidentate subacicular hook (both teeth very short, separated by a narrow angle and no additional unidentate subacicular hook in M. gili sp. nov.). Marphysa tribranchiata Liu et al., 2017 and M. schmardai Gravier, 1907 have up to three branchial filaments (up to six in M. gili sp. nov.). Marphysa brasiliensis ( Hansen, 1882) and M. mullawa Hutchings and Karageorgopolous, 2003 have branchiae from chaetigers 28–33, M. acicularum Webster, 1884 from chaetigers 27–35, and M. victori from 29 to 33 (19–24 in M. gili sp. nov.). Marphysa victori also has three types of pectinate chaetae and M. merchangensis Abdullah et al., 2024 has five types (four in M. gili sp. nov.). Marphysa viridis Treadwell, 1917 has one type of isodont pectinate chaetae (four in M. gili sp. nov.) with fewer teeth in middle body chaetigers (14 vs. 25 in M. gili sp. nov.).

Marphysa gili sp. nov. also resembles M. gaditana and, particularly, M. sanguinea ( Table 2). However, M. gaditana may have two subacicular hooks, the second one being either unidentate (Cádiz) or bidentate ( Tunis), with the bidentate ones with triangular and laterally directed teeth (only one hook, with teeth short, round, upwards directed in M. gili sp. nov.) and their Type 4 pectinate chaetae have very long teeth tapering to very long filiform tips (not particularly long having pointed, non-filiform tips in M. gili sp. nov.). In turn, M. sanguinea has subacicular hooks with long, triangular, upwards directed teeth and start from chaetigers 21–25 (short, rounded, upwards directed teeth, starting from chaetiger 40–45 in M.gili sp. nov.), Type I pectinate chaetae with 14–15 short filiform teeth and Type 4 with 8–10 teeth with pointed tips eight times longer than wider (Type 1: 20–22, with pointed tips; Type 4: 4–13, with short filiform tips up to 10 times longer than wider in M. gili sp. nov.).

Leodice eritrocephala Risso, 1826 was described from Nice based on a single, small (i.e. 70 segments) specimen having three antennae ( Risso 1826). Notably, Nice is about 250 and 550 km far, respectively, from the Gulf of Fos and Port la Nouvelle, the two sites where we collected M. gili sp. nov.. The specimen described by Risso (1826) might be a juvenile of Marphysa as the palps (previously misidentified as outermost antennae) are the final cephalic appendages to develop during ontogeny (D.M. personal observations; Aiyar 1931, Prevedelli et al. 2007, Zanol and Budaeva 2021). Like other species of Leodice described by Risso (1826) that might belong to Marphysa , such as Leodice grunwaldi Risso, 1826 and Leodice triantennata Risso, 1826 ( Lavesque et al. 2017), the description of L. eritricephala is very brief and also lacks illustrations and type materials, thus being currently considered nomen nudum (Read and Fauchald 2024). However, despite the geographical proximity, the scarce available information strongly suggests that it could be a different species. Particularly its colouring, which was red in the anterior end and black with white spots in the remaining body (uniformly brownish, slightly darker anteriorly in M. gili sp. nov.), its white eyes with black pupils (uniformly dark brown in M. gili sp. nov.), and its cub-shaped antennae (thin, distally tapering in M. gili sp. nov.).

Etymology: The specific epithet ‘ gili’ is dedicated to Dr João Gil, worldwide renowned polychaetologist, indefatigable advocate of meticulous taxonomic work, and tireless editor of the World Polychaete Database.

Distribution: Western Mediterranean: Bay of Fos and off Port La Nouvelle ( France).

Chaetiger 205 216–233 175 128(67) 138–270

number

Body length 122 89–105 60 49(40, incomplete) 48.4–163.1

(mm)

Body width 6.5 7–8 5.2 6.5(7.5) 3.7–6.6

(mm)

Chaetiger lenght up to 15 up to 13 13 up to 12(18) 10–15

vs. width

Antenae central/ 2/3 3/5 1/1 2(4) 1/2

lateral (up to chaetiger)

Palps (up to 2/3 2/3 peristomium 2 peristomium chaetiger)

Mx I 1 + 1, brown with 1 + 1, brown with white 1 + 1, brown 1 + 1, brown with 1 + 1

dark tips tips with white white tips tips

Mx II 5 + 6 brown with 8 + 7, brown with some 4 + 4, brown 4 + 4(4-4), brown 3–4 + 5

dark tips white tips with dark tips with white tips

Mx III 5 + 0 brown with 7 + 0, brown with some 7 + 0, brown 7 + 0(6 + 0), brown 6–7 + 0

dark tips white tips with some with slightly whitish white tips upper side

Mx IV 3 + 5 brown with 3 + 8, brown with some 4 + 7, brown 4 + 6(3 + 6), brown 4 + 5–6

dark tips white tips with whitish with whitish upper upper side side

Mx V 1 + 1, brown 1 + 1, pale brownish 1 + 1, whitish 1 + 1, whitish 1 + 1

Notopodial cirri triangular, tapering; triangular, tapering; longer triangular, triangular, tapering; Elongate, triangular, longer (anterior (anterior and median), tapering; longer (anterior and digitiform in last and median), shorter (posterior) and longer (an- median), shorter chaetigers, longer shorter (pos- longer (posterior-most) terior and me- (posterior) and than chaetal lobes terior) and longer than chaetal lobes dian), shorter longer (posterior-

(posterior-most) (posterior) most) than chaetal than chaetal and longer lobes lobes (posteriormost) than chaetal lobes

Branchiae 20/25–195 19/24–174/223 22/24–126 19–112(24–?) 13/21–133/255

(chaetigers)

Branchial filaments up to 4 up to 5 up to 3 up to 3(4) up to 4–6

Maximum number 39-160 49–66 35/35– 50–73(65, right?

from chaetiger 103/110 side–?)

Neuropodial up to 6, golden up to 4(5), golden brown up to 4, golden up to 3(4), brownish, up to 4, dark brown aciculae brown brown with golden tips

Table 2 (cont.) Cádiz Arcachon (NL126) Tunis Fos(PLN) M. sanguinea

Subacicular hook from chaetiger from chaetigers 44/72, from chaetiger from chaetiger 40(45), from chaetiger 40/55, absent absent form many para- 42/65, light present in all para- 21/25, absent from from some podia (completely absent yellow, podia, dark yellow, some chaetigers, parapodia, dark in two specimens), dark bidentate, slightly bidentate, darkish basally and yellow, bidentate yellow, bidentate, with covered by with round tips translucent distally, with round tips, round tips laterally dir- two guards. upwards directed, bidentate with covered by two ected, covered by two covered by two thick short round tips guards; some- guards, in some para- guards; second hook upwards directed, times a second podia of one specimen, in some parapodia, covered by two one, unidentate, a second bidentate hook similar to main one. guards.

withouth guards. covered by two guards.