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

• Main Authors: Carrerette, Orlemir, Nogueira, João Miguel De Matos
• Format: Text
• Language: unknown
• Published: Zenodo 2013
• Subjects: Biodiversity; Taxonomy; Animalia; Annelida; Polychaeta; Terebellida; Terebellidae; Polycirrus; Polycirrus breviuncinatus; Arctic; Canada; Pacific; Norway; North Pole; Medusa; Stripe; Fang; Malmgren; Antarc*; Antarctica; antarcticus; Spitsbergen
• Online Access: https://dx.doi.org/10.5281/zenodo.6165218; https://zenodo.org/record/6165218

Polycirrus breviuncinatus sp. nov. (Figures 7–8; Tables 2, 5) Type series. Holotype and paratype 1 coll. 06.Jul. 2009 (22 º 3 ' 37.240 "S 40 º 24 ' 15.840 "W, 55 m); holotype MZUSP 1220; paratype 1 ZUEC 11816. Paratype 2 coll. 07.Feb. 2009 (21 º 56 ' 7.716 "S 39 º 57 ' 51.396 "W, 720 m); MZUSP 1245. Material examined. HABITATS /PETROBRAS Project: State of Rio de Janeiro – Continental Shelf: 22 º 3 ' 37.240 "S 40 º 24 ' 15.840 "W, 55 m, 2 specs, coll. 06.Jul. 2009. Continental Slope/Canyons: 21 º 56 ' 7.716 "S 39 º 57 ' 51.396 "W, 720 m, 1 spec., coll. 07.Feb. 2009. Additional material examined for comparison. Polycirrus variabilis Hutchings & Glasby, 1986. Holotype: AM W 199538. Description. Small-sized, anteriorly swollen worm, progressively tapering from midbody, coiled after notopodia terminate (Fig. 7 A–D). Holotype incomplete, with 34 (34–45) segments, 4.9 (4.9 – 1.8) mm long, 0.3 (0.3–0.8) mm wide (Table 5). 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 7 B–D; 8 A); swollen distal part terminating far from anterior margin of lip (Fig. 7 B–C); two types of buccal tentacles, long tentacles distally expanded, short tentacles uniformly cylindrical. Peristomium restricted to lips; circular upper lip, folded in three lobes; lower lip developed, reaching posterior margin of segment 2 (Figs 7 B, D; 8 A). Segment 1 not conspicuous around body; segment 2 distinctly narrower than following segments (Figs 7 B; 8 A). Rectangular, glandular, smooth ventro-lateral pads, separated from each other within pairs by mid-ventral groove extending from segment 2, right after termination of lower lip; ventro-lateral pads progressively narrower from segment 9 to last, on segment 13; wide groove on anterior segments, as narrow stripe from termination of notopodia (Fig. 7 A–B). Cylindrical notopodia extending to segment 15, with rounded post-chaetal lobe (Fig. 8 B–D); last pair of notopodia distinctly shorter. Notochaetae progressively shorter ventralwards within each row, both anterior and posterior rows with narrowly winged notochaetae sensu Nogueira et al. (2010), those of the anterior row about twice length of those from posterior row (Figs 7 E; 8 C–E). Neuropodia beginning from last segment with notopodia, segment 15; 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 7 F; 8 F–G), small uncini, longer than high, with pointed prow, short triangular heel, slightly curved back, short dorsal button near base of main fang, and crest with three transverse rows of secondary teeth, first row with three teeth, central tooth distinctly longer, following rows with smaller teeth of variable sizes (Fig. 8 F–G). Nephridial and genital papillae not visible. Pygidial papillae not observed. Remarks. Polycirrus breviuncinatus sp. nov. , also belongs to Group 1 A sensu Glasby and Glasby (2006), and it has narrowly winged notochaetae on both rows. Such a combination of characters is also shared by P. al bi c an s (Malmgren, 1866), P. a n t a rc t i c u s (Willey, 1902), P. latidens Eliason, 1962, P. m e du s a Grube, 1850, P. norvegicus Wollebaek, 1912, P. ro s e a Hutchings & Murray, 1984, P. tenuisetis Langerhans, 1881, and P. variabilis Hutchings & Glasby, 1986 (Table 1). Of all those species, only P. tenuisetis has been recorded in Brazilian waters. In addition to the type of uncini and the presence of narrowly winged notochaetae on both rows, P. breviuncinatus sp. nov. , is also characterized for having smooth ventro-lateral pads on segments 2–13, as well as notopodia extending to segment 15, with rounded post-chaetal lobe, and neuropodia beginning from the last segment. Polycirrus albicans was described from Spitsbergen, northern Atlantic, close to the North Pole. It is different from P. breviuncinatus sp. nov. , in having 16 pairs of notopodia, i.e., up to segment 18, and neuropodia from segment 16 (Glasby & Glasby 2006) (Tables 1–2). Polycirrus antarcticus was originally described from Antarctica and differs from P. breviuncinatus sp. nov. , in having only 9 pairs of notopodia, i.e., until segment 11, and neuropodia from the segment 16 (Hessle 1917) (Table 1). According to Holthe (1986 b), P. latidens , described from material from the Skagerrak Strait, Baltic Sea, differs from P. breviuncinatus sp. nov. , in having 12 pairs of notopodia, neuropodia beginning from first segment after notopodia terminate, segment 15, ventro-lateral pads on segments 3–8, and nephridial and genital papillae on segments 4–9. Therefore, besides the differences in the number of pairs of notopodia and the segment on which first pair of neuropodia appears, P. breviuncinatus sp. nov. , differs from P. latidens by having ventro-lateral pads on segments 2–13, and inconspicuous nephridial and genital papillae (Tables 1–2). Polycirrus medusa , which is the type species of the genus, was described from the Mediterranean Sea and has been recorded from the Arctic, Boreal Eastern and Western Atlantic, and Boreal Western Pacific (Holthe 1986 a). According to Hessle (1917), P. m e d u s a is different to P. breviuncinatus sp. nov. , as it has 8–11 pairs of notopodia, neuropodia starting from segment 16, and nephridial and genital papillae on segments 3–8 (Table 1). Polycirrus norvegicus was originally described from Norway and was also recorded for the Atlantic Coast of Canada (Holthe 1986 a). According to Hessle (1917), P. norvegicus has 14–20 pairs of notopodia, neuropodia beginning from segments 10–15, and nephridial and genital papillae on segments 3–8 (Table 1). Polycirrus rosea was originally described from New South Wales, Australia, and according to the original description (Hutchings & Murray 1984), it differs from P. breviuncinatus sp. nov. , by having 10 pairs of notopodia and neuropodia beginning from segment 9. Polycirrus tenuisetis was originally described from the Atlantic Ocean, Madeira Island, and has been recorded for the Brazilian coast (Morgado & Amaral 1989). According to the literature (Fauvel 1927; Day 1961, 1967), it has variable number of pairs of notopodia, between 12–19 pairs, extending to segments 14–21, and neuropodia beginning from segment 9–12. In contrast, P. breviuncinatus sp. nov. , has a single chaetiger with biramous parapodia, as neuropodia begin from the last segment with notopodia (see Tables 1–2). Finally, P. variabilis was originally described from Australia and is distinguished from P. breviuncinatus sp. nov. , in having 15 pairs of notopodia, neuropodia beginning from segment 18, and ventro-lateral pads with large and raised glandular papillae (Hutchings & Glasby 1986 (Table 1–2). Etymology. We attribute the epithet “ breviuncinatus ” to this taxon in reference to the small size of its uncini. : Published as part of Carrerette, Orlemir & Nogueira, João Miguel De Matos, 2013, Four new species of Polycirrus Grube, 1850 (Polychaeta: Terebellidae) from Campos Basin, southeastern Brazil, pp. 146-172 in Zootaxa 3626 (1) on pages 163-165, DOI: 10.11646/zootaxa.3626.1.6, http://zenodo.org/record/218715