Amphitrite fauveli, Jirkov & Ravara & Cunha, 2018

Jirkov, Igor A., Ravara, Ascensão & Cunha, Marina R., 2018, Amphitrite fauveli sp. n. (Polychaeta: Terebellidae) from the Bay of Biscay and the Gulf of Cadiz (NE Atlantic), Invertebrate Zoology 15 (1), pp. 85-91 : 88-91

Amphitrite fauveli sp.n.

Figs 2–4.

Material examined. Atlantic Ocean. Bay of Biscay. Tributary of Cap Breton canyon, St M 84-5_ 677, 214 m, 1 large specimen ( NHM ANEA 2017.194 , Holotype) ; Saint Nazaire canyon, St M 84-5_649, 1105 m, 1 specimen ( DBUA0001973 ) . Gulf of Cadiz : Darwin MV, St B 09-14b_02W, 1100 m, 1 gravid female ( DBUA0001953 ) ; St TTR16_AT608, 1115 m, 1 specimen without branchae on one side ( DBUA0001962 ) ; Captain Arutynov MV, St MSM01/3_212, 1317 m, 1 small specimen ( DBUA0001963 ) .

DESCRIPTION (based on holotype and paratypes). Length up to 80 mm, 5 mm width, near 100 S. Buccal tentacles short, near 1/5 of body length. Eyespots absent. Branchiae consisting of numerous cirriform filaments attached directly to short thick symmetric wart like stem, which is small in the smaller worms and larger in holotype ( Fig. 2C). Number of filaments in the holotype: BS1 — 15 , BS2 — 10 , BS3 — 8 . Specimen from St MSM01/3_212 has no branchia on the left side of S1 and on the right side of S3; no scars were found. S1 forms a small lower lip ( Fig. 2E, F). Lobes of S2–S4 distinct ( Fig. 2F, G): S2 — low, lateral dorsal margin higher and disappearing ventrally; S3 — semicircular reaching the upper margin of first uncinigerous row, S4 — smaller and more dorsal, slowly disappearing ventrally. 17 TC. Ventral pads until C10, smooth ( Fig. 2E). Notochaetae long and smooth, bilimbate and short, geniculated with serrated tips ( Fig. 3). Uncini avicular from C2 facing forward, similar in thorax ( Fig. 4A) and abdomen ( Fig. 4B), but the thoracic ones slightly larger and with a more developed heel. On C 8–C17 the uncini are in double rows, face-to-face, with rows well apart ( Fig. 4C). All abdominal uncini in single rows facing forward. Thoracic unicinigerous rows large, the nine anterior almost reaching the ventral pads ( Fig. 2E). Length of the uncinigerous row of TU1 slightly smaller than TU2 , but in all anterior neuropodia equal to or larger than the width of the widest ventral pad. All thoracic neuropodia are tori (transversal cushion, uncini are situated in a medial furrow Fig. 2H TC17 ), abdominal neuropodia gradually transformed into fan-like rectangular pinnules posteriorly ( Fig. 2H AU1 , AU26 ), but uncini are not situated at the margin as it is in pinnuli of Ampharetidae . Uncinigerous row of AU1 half the length of the row from last TU. A pair of nephridial papillae present in S3 ( BS2 ) laterally to branchiae, very large, almost half the size of notopodia of TC1 ( BS3 ); absent in S4 and S5; present again between notopodiaandneuropodiaofS6–S8, muchsmall- er than in S3 ( Fig. 2F). The gravid female presents inflated shields instead of papillae in S6–S8, papillae of S3 normally developed ( Fig. 2G). Pygidium with crenulated margins, without papillae .

DIFFERENTIAL DIAGNOSIS. Three species of Amphitrite have cirriform branchia. The new species differs from two of them by the smaller number of nephridial papillae ( 8 in A. cirrata , 7 in A. kerguelensis , 4 in A. fauveli sp.n.). The third species A. oculata from Japan and Australia has also four segments with nephridial papillae but it has eyespots, absent in A. fauveli sp.n.

REMARKS. A. cirrata profunda Fauvel, 1909 was recorded from off the Azores and Morocco at depths between 778–1287 m and probably is the same species as described here. However, according to the International Code of Zoological Nomenclature ( ICZN, 1999), A. cirrata profunda should be interpreted as nomen nudum as it fails to conform to Article 12 (Article 12.1: “To be available, every new name published before 1931… must be accompanied by a description or a definition of the taxon that it denotes”). The only sentence describing this taxon is “Ils sont principalement caractérisés par le petit nombre et la forme relativement trapue de leurs filets branchiaux” ( Fauvel, 1909: 26) which can not be interpreted as a description or definition of a taxon. The number of cirri of the single branchia depends on the size of worm, while the shape of cirri depends on degree of relaxation during fixation. Thus none of the characters mentioned by Fauvel (1909) allow us to distinguish this taxon from the ones previously known. Furthermore, Solís-Weiss et al. (2004) did not list Fauvel’s material in the collection of the Muséum national d’Histoire naturelle, Paris where to all alcohol-preserved specimens were transferred. So there is no other way than to describe the new species.

ETYMOLOGY. The species is named after Prof. P. Fauvel who reported A. cirrata profunda , a probable synonym of the new species.

Acknowledgements

Thanks are due to the chief-scientists, scientific parties and crews of the cruises TTR16 (RV Prof. Logatchev, Training Through Research Programme, IOC-UNESCO), MSM01-03 (RV Maria S Merian), and B09-14b (RV Belgica).

This work was supported by CESAM (UID/ AMB/50017/2013) financed by FCT/MEC through national funds and co-funded by the FEDER within the PT2020 Partnership Agreement and Compete 2020, by EURODEEP/0001/ 2007 (project CHEMECO, ESF EuroDEEP programme), by the European Commission Sixth Framework Programme (FP6) under the HERMES project (EC contract GOCE-CT-511234), and by Seventh Framework Programme (FP7) under the HERMIONE project (EC contract 226354). The first author was supported by the Fauna Ibérica project (Fauna Ibérica XI: Polychaeta VI: Palpata-Canalipalpata I, CGL2014- 53332-C5-3-P) and by the Russian Science Foundation (grant number 14-50-00029) for investigation within Russia. The second author was supported by a postdoctoral grant (SFRH/BPD/ 112408/2015) from FCT co-financed by ESF.