Prionospio multisetosa Delgado-Blas & Peraza, 2024

Hektoen, Martin M., Radashevsky, Vasily I. & Bakken, Torkild, 2025, Partial revision of northern European Prionospio Malmgren, 1867 (Annelida: Spionidae), European Journal of Taxonomy 1027, pp. 1-58 : 14-20

Prionospio multisetosa Delgado-Blas & Peraza, 2024

Figs 6–7

Prionospio multisetosa Delgado-Blas & Peraza, 2024: 69–82 , figs 4a–t, 5a–b.

Prionospio steenstrupi – Söderström 1920: 232–233, figs 136–140 (partim).

Prionospio dubia – Sigvaldadóttir & Mackie 1993: 211–215, figs 6–8. — Sigvaldadóttir 2002: 210–211. Prionospio cf. dubia – Hektoen et al. 2024: figs 1, 4.

Prionospio ( Prionospio) steenstrupi – Hartmann-Schröder 1996: 327–328 (partim).

Prionospio ( Prionospio) dubia – Dagli & Cinar 2009: 6 .

Non Prionospio ( Prionospio) dubia – Maciolek 1985: 336–339, figs 2–3. — Imajima 1990: 118–120, figs 8–9. — Blake 1996: 130–133, fig. 4.12.

Diagnosis

Prostomium narrow, anteriorly rounded, posteriorly extending to end of chaetiger 1 as a narrow caruncle. Eyes absent. Four pairs of branchiae on chaetigers 2–5; branchiae of chaetiger 2 up to 5 × as long as other pairs. Branchiae on chaetigers 2 and 5 densely pinnate almost to tip, on chaetigers 3 and 4 apinnate; pinnules long and digitiform. Dorsal crests absent. Neuropodial postchaetal lamellae of chaetiger 3 upwards pointing. Sabre chaetae in neuropodia from chaetigers 17–22. Hooded hooks in neuropodia from chaetigers 18–22.

Material examined

FRANCE • 10 specs; Bay of Biscay ; 43°43.200′ N, 3°47.802′ W; depth 641 m; 19 Jul. 1967; H. Sanders leg.; stn 56; epibenthic sled; USNM 65931 • 2 specs; Bay of Biscay ; 43°46.698′ N, 3°37.800′ W; depth 2379 m; 18 Jul. 1967; H. Sanders leg.; stn 50; epibenthic sled; USNM 65930 .

MAURITANIA • 1 spec.; 16°22.698′ N, 16°51.972′ W; depth 509 m; 8 Nov. 2011; CCLME exped.; stn 2011410-GR10; van Veen grab; ZMBN 152650 • 7 specs; same data as for preceding; ZMBN 152604 .

MOROCCO • 2 specs; 28°52.026′ N, 12°34.176′ W; depth 495 m; 6 Jun. 2011; CCLME exped.; stn 2011410-GR35; van Veen grab; ZMBN 112312 • 1 spec.; 33°46.164′ N, 7°41.424′ W; depth 99 m; 15 Nov. 2011; CCLME exped.; stn 2011410-GR55; van Veen grab; ZMBN 152578 .

NORWAY – Norwegian Sea • 2 specs; 61°13.050′ N, 2°16.677′ E; depth 218 m; 28 May 2014; stn GFC-30; van Veen grab; ZMBN 152582 • 1 spec.; 61°22.622′ N, 2°6.729′ E, depth 280 m; 31 May 2014; stn VTG-32; van Veen grab; ZMBN 152591 • 6 specs; same data as for preceding; ZMBN 152590 • 6 specs; 61°22.629′ N, 2°6.581′ E; depth 284 m; 28 May 2011; stn VGPT2-10_2011; van Veen grab; ZMBN 152593 . – Akershus • 3 specs; Drøbak; 59°38.664′ N, 10°37.152′ E; depth 100–106 m; 20 Oct. 2014; POLYSKAG leg.; stn POLYSKAG2014/10-4; sledge; ZMBN 152580 • 1 spec.; Drøbak, Stormberget; 6 Mar. 1953; M.E.H-B.C leg.; dredge; NHMO • 2 specs; Asker, Håøyfjorden; 59°40.812′ N, 10°33.156′ E; depth 57 m; 4 Aug. 2021; NIVA leg.; stn STZ-4+3; van Veen grab; NTNU-VM 84022 . – Vestfold • 1 spec.; Larvik, Larviksfjorden; 59°2.667′ N, 10°1.537′ E; depth 43 m; 2020; NIVA leg.; stn lar-S27; van Veen grab; NTNU-VM 84020 . – Rogaland • 1 spec.; Stavanger, Boknafjorden; 59°12.833′ N, 5°46.519′ E; depth 168 m; 10 Jun. 2014; Bergen University Museum leg.; stn HM2014/06-56; van Veen grab; ZMBN 152584 • 1 spec.; Sandnes Strand; 58°56.913′ N, 5°59.179′ E; depth 250–251 m; 10 Jun. 2014; Bergen University Museum leg.; stn HM2014/06-43; sledge; ZMBN 152589 . – Vestland • 1 spec.; Øygarden Nautnes; 60°37.544′ N, 4°39.917′ E; depth 253 m; 1 May 2017; Bergen University Museum leg.; stn KB-66; van Veen grab; ZMBN 152601 • 1 spec.; Øygarden, Sund; 60°11.061′ N, 5°11.737′ E; depth 665 m; 26 Apr. 2017; Bergen University Museum leg.; stn KB-03; van Veen grab; ZMBN 152599 • 1 spec.; Aurland Aurlandsvangen; 60°54.233′ N, 7°10.088′ E; depth 115 m; 17 Nov. 2012; Bergen University Museum leg.; stn HM 2012-11-12; van Veen grab; ZMBN 152597 • 16 specs; Bjørnafjord, Saevareidfjorden; 60°8.813′ N, 5°40.206′ E; depth 235 m; 26 May 2021; Åkerblå AS leg.; stn MJÅ-REF; van Veen grab; NTNU-VM 84009 • 4 specs; Bjørnafjord, Saevareidfjorden; 60°10.436′ N, 5°42.816′ E; depth 253 m; 26 May 2021; Åkerblå AS leg.; stn MJÅ-2.2; van Veen grab; NTNU-VM 84007 • 4 specs; Bjørnafjord Saevareidfjorden; 60°10.551′ N, 5°43.070′ E; depth 237 m; 26 May 2021; Åkerblå AS leg.; stn MJÅ-3.2; van Veen grab; NTNU-VM 84008 • 2 specs; Bjørnafjord Saevareidfjorden; 60°10.581′ N, 5°43.153′ E; depth 235 m; 26 May 2021; Åkerblå AS leg.; stn MJÅ-1; van Veen grab; NTNU-VM 84006 • 2 specs; Bjørnafjord, Saevareidfjorden; 60°10.778′ N, 5°43.676′ E; depth 166 m; 26 May 2021; Åkerblå AS leg.; stn MJÅ-4; van Veen grab; NTNU-VM 84010 • 2 specs; Hardbakkeneset; 61°1.035′ N, 4°56.645′ E; depth 110 m; 19 Sep. 2019; Åkerblå AS leg.; stn HAR-3; van Veen grab; NTNU-VM 84015 • 1 spec.; Fjaler, Hegnes; 61°21.470′ N, 5°17.110′ E; depth 243 m; 4 Dec. 2019; Åkerblå AS; HEG-1; van Veen grab; NTNU-VM 84062 • 17 specs; Selje, Beitveit; 62°8.171′ N, 5°19.906′ E; depth 138 m; 10 Oct. 2019; Åkerblå AS leg.; stn BEI-3; van Veen grab; SEM stub; NTNU-VM 83988 • 20 specs; Selje, Beitveit; 62°8.551′ N, 5°20.113′ E; depth 129 m; 10 Oct. 2019; Åkerblå AS leg.; stn BEI-5; NTNU-VM 84141 . – Møre og Romsdal • 3 specs; Rauma, Skarbukta; 62°35.870′ N, 7°22.444′ E; depth 414 m; 28 Oct. 2021; Åkerblå AS leg.; stn SKA-4; van Veen grab; NTNU-VM 84019 • 2 specs; Midsund Stabben; 62°40.170′ N, 6°33.357′ E; depth 119 m; 5 Sep. 2019; Åkerblå AS leg.; stn STA-2; van Veen grab; NTNU-VM 84016 • 1 spec.; Molde, Setevika; 62°44.123′ N, 6°56.613′ E; depth 292 m; 29 Jun. 2021; Åkerblå AS leg.; stn SET-2.1; van Veen grab; NTNU-VM 84021 • 19 specs; Aukra, Sandholmane; 62°47.266′ N, 6°40.379′ E; depth 105 m; 18 Jul. 2021; Åkerblå AS leg.; stn SAN-REF; van Veen grab; NTNU-VM 84005 • 4 specs; Aukra, Sandholmane; 62°47.780′ N, 6°40.894′ E; depth 153 m; 18 Jul. 2021; Åkerblå AS leg.; stn SAN-3; van Veen grab; NTNU-VM 84002 • 1 spec.; Sandøy, Sandholmane; 62°47.780′ N, 6°40.894′ E; depth 153 m; 4 Sep. 2019; Åkerblå AS leg.; SAN-4; van Veen grab; SEM stub; NTNU-VM 84156 • 1; same data as for preceding; NTNU-VM 84041 • 17 specs; Aukra, Sandholmane; 62°48.042′ N, 6°40.451′ E; depth 150 m; 18 Jul. 2021; Åkerblå AS leg.; stn SAN-4; van Veen grab; NTNU-VM 84003 • 15 specs; same data as for preceding; NTNU-VM 84001 • 18 specs; Aukra, Sandholmane; 62°48.068′ N, 6°39.863′ E; depth 102 m; 18 Jul. 2021; Åkerblå AS leg.; stn SAN-5.2; van Veen grab; NTNU-VM 84004 • 7 specs; Aukra Fausken; 62°53.858′ N 6°43.390′ E; depth 130 m; 17 Jun. 2021; Åkerblå AS leg.; stn FAU-4; van Veen grab; NTNU-VM 84000 • 6 specs; Gjemnes, Slettnes Vest; 62°57.660′ N, 7°50.739′ E; depth 135 m; 27 May 2021; Åkerblå AS leg.; stn SLE-REF; van Veen grab; NTNU-VM 84014 • 5 specs; Gjemnes, Slettnes Vest; 62°57.670′ N, 7°51.966′ E; depth 163 m; 27 May 2021; Åkerblå AS leg.; stn SLE-5; van Veen grab; NTNU-VM 84013 • 1 spec.; Tingvoll, Halsbukta; 63°4.952′ N, 8°8.815′ E; depth 343 m; 2 Jun. 2021; Åkerblå AS leg.; stn hal-3; van Veen grab; NTNU-VM 84011 • 1 spec.; Tingvoll, Halsbukta; 63°4.219′ N, 8°8.888′ E; depth 304 m; 2 Jun. 2021; Åkerblå AS leg.; stn hal-4; van Veen grab; SEM stub; NTNU-VM 84153 • 1 spec.; same data as for preceding; NTNU-VM 84012 • 9 specs; Averøy, Skjellingen; 63°8.698′ N, 7°33.211′ E; depth 111 m; 5 Jul. 2021; Åkerblå AS leg.; stn SKJ-1.4; van Veen grab; NTNU-VM 84017 • 1 spec.; Aure Hagahammaren; 63°8.027′ N, 8°1.332′ E; depth 207 m; 22 May 2019; Åkerblå AS leg.; stn HAG-2; van Veen grab; SEM stub; NTNU-VM 84155 • 1 spec.; same data as for preceding; NTNU-VM 83992 • 5 specs; Aure, Hagahammaren; 63°8.187′ N, 8°2.185′ E; depth 213 m; 22 May 5 2019; Åkerblå AS leg.; stn HAG-5; van Veen grab; NTNU-VM 83991 . – Trøndelag • 1 spec.; Hitra, Vaerøya; 63°24.700′ N, 8°28.885′ E; depth 205 m; 21 May 2021; Åkerblå AS leg.; stn VAER-REF; van Veen grab; SEM stub; NTNU-VM 84154 • 4 specs; same data as for preceding; NTNU-VM 84018 • 6 specs; Indre Fosen, Frengåsen; 63°42.106′ N, 9°52.857′ E; depth 91 m; 23 Jun. 2021; Åkerblå AS leg.; stn FRE-2; van Veen grab; NTNU-VM 83994 • 1 spec.; Indre Fosen, Frengåsen; 63°42.157′ N, 9°53.129′ E; depth 98 m; 23 Jun. 2021; Åkerblå AS leg.; stn FRE-3.2; van Veen grab; NTNU-VM 83995 • 4 specs; Indre Fosen, Frengåsen; 63°42.210′ N, 9°53.399′ E; depth 120 m; 23 Jun. 2021; Åkerblå AS leg.; stn FRE-1; van Veen grab; NTNU-VM 83993 • 2 specs; Indre Fosen, Frengåsen; 63°42.334′ N, 9°53.802′ E; depth 162 m; 23 Jun. 2021; Åkerblå AS leg.; stn FRE-4; van Veen grab; NTNU-VM 83996 • 1 spec.; Indre Fosen, Frengåsen; 63°42.436′ N, 9°53.802′ E; depth 196 m; 23 Jun. 2021; Åkerblå AS leg.; stn FRE-5.1; van Veen grab; NTNU-VM 83997 • 1 spec.; Skjoldryggen; 65°30.034′ N, 6°16.109′ E; depth 397 m; 23 Jun. 2013; MAREANO leg.; stn R1119-67; van Veen grab; ZMBN 152585 . – Troms • 1 spec.; Tranøy, Gjervika; 69°2.628′ N. 16°51.239′ E; depth 160 m; 30 Oct. 2019; Åkerblå AS leg.; stn GJE-REF; van Veen grab; NTNU-VM 83999 • 1 spec.; Tranøy Gjervika; 69°2.796′ N, 16°53.047′ E; depth 250 m; 30 Oct. 2019; Åkerblå AS leg.; stn GJE-4.1; van Veen grab; SEM stub; NTNU-VM 84152 • 4 specs; same data as for preceding; NTNU-VM 83998 .

SENEGAL • 3 specs; 14°27.576′ N, 17°36.624′ W; depth 489 m; 5 Nov. 2011; CCLME exped.; stn 2011410-GR08; van Veen grab; ZMBN 152596 • 3 specs; 15°28.812′ N, 17°13.566′ W; depth 504 m; 7 Nov. 2011; CCLME exped.; stn 2011410-GR09; van Veen grab; ZMBN 152588 .

SWEDEN • 1 spec.; Varberg , Värö; 57°10′ N, 12°1′ E; depth 47 m; 1981; stn VÄRH81#3; van Veen grab; SMNH 11281 • 1 spec.; same data as for preceding; 1978; stn VÄRH78#3; van Veen grab; SMNH 8105 • 1 spec.; same data as for preceding; SMNH 6450 • 1 spec.; same data as for preceding; 1979; stn VÄRV79#3; van Veen grab; SMNH 9009 • 1 spec.; same data as for preceding; SMNH 8716 • 2 specs; same data as for preceding; 1980; VÄRV80 #3; van Veen grab; SMNH 9667 • 3 specs; same data as for preceding; 1984; VÄRV84 #3; van Veen grab; SMNH 53676 .

WESTERN SAHARA • 1 spec.; 25°3.900′ N, 16°18.612′ W; depth 568 m; 25 Nov. 2011; CCLME exped.; stn 2011410-GR20; van Veen grab; ZMBN 152587 • 19 specs; 26°27.402′ N, 14°30.612′ W; depth 435 m; 29 Nov. 2011; CCLME exped.; stn 2011410-GR24; van Veen grab; ZMBN 152595 .

Examined material with sequence data

GUINEA • 1 spec.; 9°38.724′ N, 16°40.002′ W; depth 509 m; 15 May 2012; CCLME exped.; stn 2012404-GR03; van Veen grab; ZMBN 152594 .

MAURITANIA • 1 spec.; 16°22.698′ N, 16°51.972′ W; depth 509 m; 8 Nov. 2011; CCLME exped.; stn 2011410-GR10; van Veen grab; ZMBN 152602 • 1 spec.; 17°20.538′ N, 16°46.590′ W; depth 572 m; 1 Jun. 2012; CCLME exped.; stn 2012404-GR28; van Veen grab; ZMBN 114671 .

MOROCCO • 1 spec.; 28°52.026′ N, 12°34.176′ W; depth 495 m; 6 Jun. 2011; CCLME exped.; stn 2011410-GR35; van Veen grab; ZMBN 152581 • 1 spec.; 33°46.164′ N, 7°41.424′ W; depth 99 m; 15 Nov. 2011; CCLME exped.; stn 2011410-GR55; van Veen grab; ZMBN 152759 .

NORWAY – Norwegian Sea • 1 spec.; 61°13.050′ N, 2°16.677′ E; depth 218 m; 28 May 2014; stn GFC-30; van Veen grab; ZMBN 152598 • 1 spec.; 61°22.629′ N, 2°6.581′ E; depth 284 m; 28 May 2011; stn VGPT2-10_2011; van Veen grab; ZMBN 152583 . – Akershus • 1 spec.; Drøbak; 59°38.664′ N, 10°37.152′ E; depth 100–106 m; 20 Oct. 2014; POLYSKAG leg.; stn POLYSKAG2014/10-4; sledge; ZMBN 152603 . – Rogaland • 1 spec.; Stavanger, Boknafjorden; 59°12.833′ N, 5°46.519′ E; depth 168 m; 10 Jun. 2014; Bergen University Museum leg.; stn HM2014/06-56; van Veen grab; ZMBN 152584 • 1 spec.; Sandnes Strand; 58°56.913′ N, 5°59.179′ E; depth 250–251 m; 10 Jun. 2014; Bergen University Museum leg.; stn HM2014/06-43; sledge; ZMBN 152589 . – Vestland • 1 spec.; Øygarden Nautnes; 60°37.544′ N, 4°39.917′ E; depth 253 m; 1 May 2017; Bergen University Museum leg.; stn KB-66; van Veen grab; ZMBN 152601 • 1 spec.; Øygarden, Sund; 60°11.061′ N, 5°11.737′ E; depth 665 m; 26 Apr. 2017; Bergen University Museum leg.; stn KB-03; van Veen grab; ZMBN 152599 • 1 spec.; Aurland Aurlandsvangen; 60°54.233′ N, 7°10.088′ E; depth 115 m; 17 Nov. 2012; Bergen University Museum leg.; stn HM 2012-11-12; van Veen grab; ZMBN 152597 • 1 spec.; Selje, Beitveit; 62°8.171′ N, 5°19.906′ E; depth 138 m; 10 Oct. 2019; Åkerblå AS leg.; stn BEI-3; van Veen grab; SEM stub; NTNU-VM 83989 . – Trøndelag • 1 spec.; Ørland, Brekstad; 63°39.444′ N, 9°38.025′ E; depth 260–278 m; 24 Oct. 2016; stn 2016041; sledge; ZMBN 114364 • 1 spec.; Haltenbanken; 64°8.214′ N, 8°43.170′ E; depth 233 m; 5 Oct. 2013; MAREANO leg.; stn R890-105; van Veen grab; ZMBN 152600 – Troms • 1 spec.; Tranøy, Gjervika; 69°2.628′ N. 16°51.239′ E; depth 250 m; 30 Oct. 2019; Åkerblå AS leg.; stn GJE-4; van Veen grab; NTNU-VM 83990 .

REPUBLIC OF THE CONGO • 1 spec. 4°29.616′ S, 10°55.878′ E; depth 202 m; 12 May 2008; GCLME exped.; stn 8CR-01; van Veen grab; ZMBN 114799 .

SENEGAL • 1 spec.; 15°28.812′ N, 17°13.566′ W; depth 504 m; 7 Nov. 2011; CCLME exped.; stn 2011410-GR09; van Veen grab .

WESTERN SAHARA • 1 spec.; 26°27.402′ N, 14°30.612′ W; depth 435 m; 29 Nov. 2011; CCLME exped.; stn 2011410-GR24; van Veen grab; ZMBN 152592 .

Comparative material

Prionospio gayheadia Delgado-Blas & Peraza, 2024

UNITED STATES – Massachusetts •>25 specs; 40°1.248′ N, 70°55.086′ W; depth 250 m; 4 May 1985; Battelle-New England Marine Lab For BLM/ MMS leg.; USNM 1002841 •> 25 specs;same data as for preceding; USNM 1002842 •> 25 specs; 40°1.302′ N, 70°55.098′ W; depth 250 m; 4 May 1985; Battelle-New England Marine Lab For BLM/ MMS leg.; USNM 1002843 • 2 specs; Georges Bank, Lydonia Canyon ; 40°27.468′ N, 67°40.266′ W; depth 556 m; 6 Jul. 1985; Battelle-New England Marine Lab For BLM/ MMS leg.; USNM 1002845 • 1 spec.; 39°48.252′ N, 70°54.948′ W; depth 1273 m; 30 Jul. 1986; Battelle-New England Marine Lab For BLM/ MMS leg.; USNM 1002854 • 1 spec.; 30°3.420′ N, 88°38.080′ W; depth 20 m; 20 Aug. 1988; D. Harper leg.; box corer; USNM 1573961 • 2 specs; 29°4.932′ N, 88°45.516′ W; depth 150 m; 11 Mar. 1988; D. Harper leg.; box corer; USNM 1573962 • 1 spec.; 29°16.302′ N, 88°6.498′ W; depth 150 m; 21 Aug. 1988; D. Harper leg.; box corer; USNM 1573963 • 1 spec.; 29°16.302′ N, 88°6.498′ W; depth 150 m; 16 Mar. 1988; D. Harper leg.; box corer; USNM 1573964 • 3 specs; 29°42.084′ N, 87°20.166′ W; depth 100 m; 13 Mar. 1988; D. Harper leg.; box corer; USNM 1573965 . – Florida • 1 spec.; 29°40.500′ N, 89°16.002′ W; depth 200 m; 23 Aug. 1988; D. Harper leg.; box corer; USNM 1573982 • 2 specs; 29°42.084′ N, 87°20.166′ W; depth 100 m; 16 Mar. 1988; D. Harper leg.; box corer; USNM 1573983 • 2 specs; same data as for preceding; USNM 1573987 • 1 spec.; 30°2.118′ N, 88°38.082′ W; depth 20 m; 19 Aug. 1988; D. Harper leg.; box corer; USNM 1573984 • 1 spec.; 30°2.118′ N, 88°38.082′ W; depth 20 m; 12 Mar. 1988; D. Harper leg.; box corer; USNM 1573985 • 1 spec.; same data as for preceding; USNM 1573986 • 1 spec.; 29°24.000′ N, 88°7.002′ W; depth 100 m; 17 Mar. 1988; D. Harper leg.; box corer; USNM 1573988 • 1 spec.; 29°42.084′ N, 87°20.166′ W; depth 100 m; 22 Aug. 1988; D. Harper leg.; box corer; USNM 1573989 • 3 spec.; 29°24.000′ N, 88°7.002′ W; depth 100 m; 20 Aug. 1988; D. Harper leg.; box corer; USNM 1573990 • 3 specs; same data as for preceding; USNM 1573991 • 2 specs; 29°42.084′ N, 87°20.166′ W; depth 100 m; 16 Mar. 1988; D. Harper leg.; box corer; USNM 1573992 • 3 specs; 29°40.500′ N, 89°16.002′ W; depth 200 m; 23 Aug. 1988; D. Harper leg.; box corer; USNM 1573993 • 1 spec.; 29°48.000′ N, 87°22.800′ W; depth 40 m; 16 Mar. 1988; D. Harper leg.; box corer; USNM 1573994 • 1 spec.; 29°24.000′ N, 88°7.002′ W; depth 100 m; 20 Aug. 1988; D. Harper leg.; box corer; USNM 1573995 • 2 specs; 29°14.898′ N, 88°7.284′ W; depth 200 m; 20 Aug. 1988; D. Harper leg.; box corer; USNM 1573996 .

Remarks

Prionospio multisetosa was described by Delgado-Blas & Peraza (2024) during the preparation of the present manuscript. We were not able to examine the type material, and given the thorough and detailed original description, we did not find it necessary to provide a full redescription here. Instead, we present additional observations based on a larger number of specimens from a broader geographic and bathymetric range, contributing further information on the intraspecific variability and distribution of the species.

Delgado-Blas & Peraza (2024) based the description of P. multisetosa on 15 specimens from the west coast of Sweden, which they compared with the descriptions (not specimens) of P. dubia from South Africa provided by Day (1961) and Wilson (1990). Earlier, Prionospio with same characteristics from northern Europe were referred by various authors to P. dubia ( Sigvaldadóttir & Mackie 1993; Sigvaldadóttir 2002). Delgado-Blas & Peraza (2024: table 1) noticed that the described South African specimens of P. dubia had 26–50 chaetigers while Swedish specimens, which they described as P. multisetosa , had 60–98 chaetigers, despite that all worms from South Africa were anterior fragments. They noted a series of morphological characters to distinguish P. multisetosa and P. dubia : presence or absence of eyes, size of the branchiae, position of the pinnules on the branchiae of chaetiger 5, whether the notopodial postchaetal lamellae extend slightly onto the dorsum or not, size of the notopodial prechaetal lamellae, shape of the notopodial postchaetal lamellae of chaetiger 3, shape of the neuropodial capillaries of chaetigers 2–5, the appearance and shape of sabre chaetae and the notopodial and neuropodial hooded hooks.

In this study, we examined 313 specimens previously identified as P. dubia from northern Norway south to the Republic of the Congo and could not find any morphological differences between Nordic and West African worms. We provide more insight into the intraspecific variation in P. multisetosa , and new images of anterior morphology ( Fig. 6A–C) and drawings of parapodia and chaetae ( Fig. 7A–H) of this species. We found some specimens with branchiae of chaetiger 2 extending to chaetiger 9, rather than to chaetiger 5, as reported by Delgado-Blas & Peraza (2024) for North Atlantic specimens, and that the branchiae of chaetigers 3 and 4 are similar in length to the notopodial postchaetal lamellae on the same chaetiger rather than shorter ( Fig. 7C–D). While it was common for the notopodial postchaetal lamellae of chaetiger 2 to have a short ventral edge, not all worms had lamellae shaped like this. The neuropodial lamellae of chaetiger 3 were dorsally pointed in most worms ( Fig. 8C), which was not clearly expressed or illustrated in the original description of P. multisetosa by Delgado-Blas & Peraza (2024). We also found slightly larger ranges of the first appearance of hooded hooks and sabre chaetae in neuropodia. The smallest juveniles ( 0.1 mm wide) had hooded hooks in neuropodia from chaetiger 14 and sabre chaetae from chaetiger 13. In comparison, Delgado-Blas & Peraza (2024) reported the first appearance of hooded hooks and sabre chaetae in neuropodia from chaetigers 16 and 14, respectively, likely due to their studying slightly larger specimens ( 0.2 mm wide).

The studied material includes all specimens sequenced by Hektoen et al. (2024), which came from the same broad geographic range, from northern Norway to the Republic of the Congo, and depths from 106 m to 665 m. Their molecular analysis confirmed their conspecificity.

To summarize, we observed a wide range of ontogenetic variability of specimens with diagnostic characters of P. dubia but could not find distinct morphological differences between them to assume the presence of more than one species. Our previous molecular analysis confirmed the conspecificity of worms collected from northern Norway south to the Republic of the Congo ( Hektoen et al. 2024). This wide distribution range combined with the minute morphological differences between P. dubia and P. multisetosa may indicate that P. multisetosa is a junior synonym of P. dubia . However, this will likely only be resolved once new material of P. dubia from South Africa is collected and sequenced.

Habitats and distribution

Originally, P. multisetosa was reported from the west coast of Sweden. Here, we provide additional records of this species from East Atlantic waters, from northern Norway south to the Republic of the Congo, from depths of 47– 665 m. Adults mainly occur in fine silt and muddy sediments.