Polycirrus nonatoi Carrerette & Nogueira, 2013, sp. nov.

Polycirrus nonatoi sp. nov.

(Figures 1–3; Tables 2–3)

Type series. Holotype and paratypes 1–3 coll. 06.Jul.2009 (23º12'4.250"S 40º59'41.700"W, 142 m); holotype MZUSP 1213; paratype 1 MZUSP 1214; paratype 2 MZUSP 1215; paratype 3 LACM-AHF Poly 4983. Paratypes 4–7 coll. 01.Sep.2009 (23º39'17.358"S 41º18'39.120"W, 692.7 m); paratype 4 LACM-AHF Poly 4984; paratype 5 ZUEC 11811; paratype 6 ZUEC 11812; paratype 7 ZUEC 11813. Paratypes 8–10 coll. 22.Jul.2009 (22º6'8.560"S 40º3'11.400"W, 150 m); paratype 8 USNM 1195838; paratype 9 USNM 1195839; paratype 10 MZUSP 1243.

Material examined. HABITATS /PETROBRAS Project: State of Rio de Janeiro – Campos Basin, Mouth of Rio Paraíba do Sul: 21º24'39.354"S 40º25'24.744"W, 33 m, 4 specs, coll. 7.Mar.2009; 21º45'9.870"S 40º14'14.082"W, 67 m, 1 spec., coll. 14.Mar.2009; 22º11'30.342"S 40º55'30.995"W, 44 m, 2 specs, coll. 17.Jul.2009; 22º6'15.635"S 40º43'47.736"W, 47 m, 1 spec., coll. 17.Jul.2009; 21º45'10.950"S 40º14'14.360"W, 66 m, 1 spec., coll. 8.Jul.2009. Continental Shelf: 23º36'10.450"S 41º21'36.230"W, 145 m, 1 spec., coll. 03.Jul.2009; 22º59'42.920"S 41º21'13.850"W, 77 m, 1 spec., coll. 04.Jul.2009; 23º10'0.720"S 41º3'12.550"W, 107 m, 1 spec., coll. 05.Jul.2009; 23º12'4.250"S 40º59'41.700"W, 142 m, 4 specs, coll. 06.Jul.2009; 23º12'4.090"S 40º59'41.770"W, 142 m, 1 spec., coll. 07.Jul.2009; 22º6'8.560"S 40º3'11.400"W, 150 m, 3 specs, coll. 22.Jul.2009; 21º9'5.449"S 40º16'13.977"W, 103 m, 1 spec., coll. 30.Jul.2009; 21º22'59.306"S 40º15'16.816"W, 140 m, 4 specs, coll. 31.Jul.2009; 23º9'59.770"S 41º3'12.776"W, 105 m, 1 spec., coll. 01.Aug.2009; 23º11'24.493"S 41º0'55.751"W, 117 m, 3 specs, coll. 02.Aug.2009; 22º46'50.511"S 41º3'39.038"W, 77 m, 1 spec., coll. 03.Aug.2009; 22º17'21.109"S 40º6'42.477"W, 143 m, 3 specs, coll. 16.Aug.2009; 22º6'6.272"S 40º3'12.696"W, 154 m, 1 spec., coll. 21.Aug.2009; 22º6'6.141"S 40º3'12.849"W, 153 m, 3 specs, coll. 22.Aug.2009; 21º9'5.797"S 40º16'13.427"W, 101 m, 1 spec., coll. 28.Aug.2009. Continental Slope/Canyons: 21º55'2.964"S 39º54'37.914"W, 996 m, 5 specs, coll. 29.Aug.2009; 21º40'13.146"S 39º58'12.810"W, 1004 m, 4 specs, coll. 31.Aug.2009; 23º39'17.358"S 41º18'39.120"W, 692.7 m, 5 specs, coll. 01.Sep.2009; 23º41'5.496"S 41º16'10.218"W; 1006.8 m, 4 specs, coll. 02.Sep.2009; 23º1'26.394"S 40º45'29.088"W, 964.8 m, 5 specs, coll. 03.Sep.2009; 23º18'28.872"S 40º47'36.264"W, 1903 m, 4 specs, coll. 04.Sep.2009.

Additional material examined for comparison. Polycirrus abrolhensis Garraffoni & Costa, 2003. Holotype: IBUFRJ–0481; paratype 1: IBUFRJ–0482. Polycirrus bicrinalis Hutchings & Glasby, 1986. Holotype: AM W199637; paratypes: AM W199638; AM W199639; AM W199640. Polycirrus paivai Garraffoni & Costa, 2003. Holotype: IBUFRJ–0484; paratypes: IBUFRJ–0486, 3 specimens.

Description. Middle-sized, anteriorly swollen worm (Figs 1 A–D; 2A–D), progressively tapering from midbody to pygidium, coiled after notopodia terminate. Holotype complete, with 69 (20–78) segments, 10.1 (4.5–16.7) mm long, 1.0 (0.5–1.2) mm wide (Table 3). Prostomium at base of upper lip, both basal and distal parts forming thick crests on dorsal surface of upper lip, basal part extending posteriorly and ventrally, terminating laterally to mouth (Figs 1 A–D; 2A–E); distal part of prostomium swollen, extending along dorsal surface of upper lip until near anterior border; distal part of prostomium protruding laterally as one tentacle-like prostomial lateral process (plp) at each side (Figs 1 B–D; 2A–E), from which originate tufts of numerous short and cylindrical buccal tentacles; prostomial lateral processes basally swollen, distally blunt, directed dorsally (Figs 1 B–D; 2A–E); two types of buccal tentacles, long tentacles distally expanded, short tentacles uniformly cylindrical. Peristomium restricted to lips (Figs 1 A–C; 2A–E); upper lip distinctly elongate, relatively narrow, convoluted, ciliated; lower lip large and densely ciliated, extending posteriorly from mouth along segment 2 midventrally (Figs 1 A–D; 2A–E). Segmentation poorly marked dorsally (Figs 1 B–D; 2C). Segment 1 conspicuous dorsally (Figs 1 B; 2B–C); segment 2 narrower than following ones. Rectangular, highly glandular, tessellated ventro-lateral pads, pairs separated from each other by mid-ventral groove extending from segment 2, right after termination of lower lip (Figs 1 A, C; 2A, D); pads progressively narrower from segment 8 to last, on segment 13 (12–13); wide groove on region with notopodia, progressively narrowing from mid-body (Figs 1 A, C; 2A, D), as narrow stripe from posterior segments with notopodia. Cylindrical, elongate notopodia extending to segment 15 (13–16), with elongate, distally blunt tentacle-like post-chaetal lobe (Fig. 2 A–D, G–I); last pair of notopodia distinctly shorter than previous ones. Notochaetae progressively shorter ventralwards within each row, those of anterior row shorter, pinnate, gradually tapering to tips; posterior row with narrowly winged notochaetae sensu Nogueira et al. (2010), with hirsute wings (Figs 1 E; 2G–I; 3A–D). Neuropodia beginning from segment 16 (14–17), first segment after termination of notopodia in all specimens; anterior neuropodia short, sessile tori, progressively more developed posteriorwards, forming prominent pinnules on posterior chaetigers. Neurochaetae type 1 uncini sensu Glasby and Glasby (2006) (Figs 1 F–G; 3E), small, longer than high, with pointed prow, short triangular heel, back distinctly bent posteriorly, short dorsal button near base of main fang, and crest with two rows of secondary teeth, first row with three teeth, central tooth distinctly longer, upper row with smaller teeth of variable sizes (Figs 1 F–G; 3E). Nephridial and genital papillae present on segments 4–9 (4–9 to 11) (Fig. 2 B, H). Pygidium surrounded by rounded papillae, larger ventral papilla, small papillae lateral and dorsally (Fig. 2 F).

Remarks. Polycirrus nonatoi sp. nov., belongs to Group 1A sensu Glasby and Glasby (2006), for having type 1 uncini and notopodia terminating before segment 20. The other species in this group are P. albicans (Malmgren, 1866), P. antarcticus (Willey, 1902), P. bicrinalis Hutchings & Glasby, 1986, P. broomensis Hartmann-Schröder, 1979, P. dodeka Hutchings, 1990, P. haematodes (Claparède, 1864), P. hesslei M onro, 1930, P. insignis Gravier, 1907, P. kerguelensis (McIntosh, 1885), P. latidens Eliason, 1962, P. m e d u s a Grube, 1850, P. nephrosus Hutchings & Glasby, 1986, P. norvegicus Wollebaek, 1912, P. paivai Garraffoni & Costa, 2003, P. plumosus (Wollebaek, 1912), P. ro s e a Hutchings & Murray, 1984, and P. variabilis Hutchings & Glasby, 1986.

In addition to the type of uncini and number of pairs of notopodia, P. nonatoi sp. nov., is also characterized for having elongate and remarkably narrow upper lip; notopodia with elongate and digitiform post-chaetal lobe and both pinnate and limbate notochaetae present; uncinial back distinctly bent posteriorly; in addition to a pair of elongate prostomial lateral processes (plp) originating from distal part of prostomium, which have never been described for any other species of Polycirrus, except for Polycirrus cf. plumosus sensu Nonato (1981), which we believe belongs to the same taxon (see below). However, prostomial lateral processes are also present in P. p a i v a i, although not mentioned in the original description (Garraffoni & Costa 2003).

Among all the taxa belonging to Group 1A sensu Glasby and Glasby (2006), four species are similar to Polycirrus nonatoi sp. nov., by having pinnate notochaetae in the anterior row, P. bicrinalis, whose type locality is in Queensland, Australia, P. broomensis, described from material from Western Australia, P. paivai, described from material from Abrolhos Archipelago, Brazil, and P. plumosus, which was originally described from Norway and has been recorded worldwide.

Polycirrus bicrinalis differs from P. nonatoi sp. nov., by lacking prostomial lateral processes, and having almost circular upper lip; ventro-lateral pads with large and raised glandular papillae, covering entire ventral surface until around segment 10; 16 pairs of notopodia (Table 1), with short post-chaetal lobes; and uncini with slightly curved back (see Nogueira et al. 2010: p. 77, Fig. 38B–C). Polycirrus nonatoi sp. nov., in contrast, has the prostomium continuing laterally as one pair of tentacle-like prostomial lateral processes, one at each side; distinctly expanded and relatively narrow upper lip; smooth ventro-lateral pads extending until segments 13 (12–13); 13 (11–14) pairs of notopodia, with elongate and digitiform post-chaetal lobe; and neuropodia bearing uncini with the back distinctly bent posteriorly.

Polycirrus broomensis differs from P. nonatoi sp. nov., as it lacks both prostomial lateral processes, and notopodial post-chaetal lobes, has poorly defined ventral-lateral pads, and uncini with slightly curved back (see Hutchings & Glasby 1986: p. 337, Fig. 7 c), while P. nonatoi sp. nov., has, in addition to what was discussed above, clearly defined ventral pads (Table 2).

Polycirrus paivai Garraffoni & Costa, 2003 was originally described from Brazilian material, collected off the Abrolhos Archipelago. Polycirrus paivai is similar to P. nonatoi sp. nov., as it has notopodia extending to segment 14 (in P. nonatoi these structures occur on segments 3 to 13–15), all with elongate post-chaetal lobe. In addition, P. paivai also shares other characters with P. nonatoi sp. nov., which were not mentioned in the original description, such as prostomial lateral processes basally swollen, distally blunt, directed dorsally, and ventro-lateral pads on segments 2–13. However, this taxon differs from P. nonatoi sp. nov., in having trilobate upper lip with convoluted lateral lobes, all notochaetae similar in size, neuropodia beginning from the penultimate segment with notopodia (Table 1), bearing uncini with slightly curved back, and nephridial and genital papillae were not visible in typematerial (OC personal observation), while in P. nonatoi sp. nov., the upper lip is distinctly elongate and relatively narrow, notopodia bear progressively shorter ventralwards notochaetae within each row, neuropodia begin from first segment after notopodia terminate, and nephridial and genital papillae are conspicuous on segments 4–9 (4–9 to 11) (Tables 1–2).

Polycirrus plumosus (Wollebaek, 1912), which is the species of Polycirrus most commonly recorded in Brazilian waters (Amaral et al. 2012), was originally described from Norway and has been recorded worldwide (Holthe 1986a, b; Kritzler 1984; Fauchald et al. 2009). This means it is possibly a complex of sibling species and more detailed studies are required to confirm the identification of this taxon in localities outside the Northern Atlantic, including Brazilian material.

The only description available for Brazilian material of Polycirrus plumosus (Nonato 1981, as P. cf. plumosus) agrees with that provided above for P. nonatoi sp. nov., including the prostomial lateral processes and the post-chaetal notopodial lobes. The few differences between the description provided by Nonato (1981) and the material herein described are probably due to the poor state of preservation of the material examined by Prof. Nonato. There are some discrepancies, however, between the available descriptions of P. plumosus from different localities (compare Wollebaek 1912; Day 1961, 1967; Kritzler 1984; Holthe 1986b; Jirkov 2001) and, except for Nonato (1981), no one mentions the prostomial lateral processes or the post-chaetal notopodial lobes. Because of those differences between descriptions from different localities, we base our comparison on the specimens from the northern Atlantic, the type locality. According to Holthe (1986b), P. plumosus has 17–19 pairs of notopodia (Table 1); in contrast, P. nonatoi sp. nov., has 11–14 pairs of notopodia (Table 2). In addition, as said before, Holthe does not mention the prostomial lateral processes or the digitiform post-chaetal lobes, both structures present in P. nonatoi sp. nov., neither are illustrated in his Figures 73A and B (Holthe 1986b: p. 158).

Finally, Polycirrus nonatoi sp. nov., also shares some characteristics with other taxa described in the present paper, as discussed in the Remarks of the following descriptions.

Etymology. We dedicate this species to Professor Edmundo Ferraz Nonato, from Instituto Oceanográfico, Universidade de São Paulo, not only for having been the first researcher who noticed the occurrence of this taxon off the Brazilian coast, although he identified it as P. cf. plumosus, but also for his great contribution to the study of Polychaeta in Brazil, as the “father, grandfather and great-grandfather” of all Brazilian polychaetologists.