Bradabyssa strelzovi (Jirkov & Filippova in Jirkov, 2001) Salazar-Vallejo, 2017

Salazar-Vallejo, Sergio I., 2017, Revision of Brada Stimpson, 1853, and Bradabyssa Hartman, 1967 (Annelida, Flabelligeridae), Zootaxa 4343 (1), pp. 1-98 : 38-39

Bradabyssa strelzovi (Jirkov & Filippova in Jirkov, 2001) n. comb.

Figure 18

Brada strelzovi Jirkov & Filippova, 2001: 356 , Figs 1–3 .– Oug et al. 2011: 15, Figs a–c (repeated from Jirkov & Filippova 2001).

Type material. Arctic Ocean, Barents Sea. One syntype (HDMSU 13.07.1926), R.V. Persey, Cruise 10, Sta. 493 (68.49° N, 44.04° W), 65 m, 13 Jul. 1926 (complete, body cylindrical, rounded in both ends, breaking into two parts, 32 mm long, 3 mm wide, cephalic cage 1.8 mm long, 31 chaetigers; gonopodial papillae in chaetiger 5, cephalic cage chaetae 2 notochaetae, 2 neurochaetae, notochaetae half as long as body width, neurospines from chaetiger 2, 2–3 per ramus, in oblique series). One syntype (HDMSU S.1970), R.V. Maslov, Summer 1970 (body cylindrical with blunt ends, 32 mm long, 3 mm wide, cephalic cage broken, 36 chaetigers; gonopodial papillae in chaetiger 5, notochaetae up to 6 per ramus, neurochaetae up to 7, in longitudinal series). One syntype (HDMSU 31.08.1969), R.V. Maslov, Sta. 242, 125 m, 31 Aug. 1969 (body fusiform, rounded in both ends, 26 mm long, 5 mm wide, cephalic cage broken, remaining chaetae 1 mm long, 27 chaetigers, gonopodial papillae in chaetiger 5, 15–16 transverse series of dorsal papillae per segment, notochaetae 1/3 as long as body width, 2 notochaetae per bundle, 3–4 neurochaetae, in transverse series). Two syntypes (HDMSU 04.07.1980), R.V. Alaid, Cruise 30, Sta. 8 (74.3° N, 32.3° W), 180–200 m, 4 Jul. 1980 (fusiform, anterior region swollen, constricted posterior region; 19–24 mm long, 6 mm wide, cephalic cage 1.0– 1.6 mm long, 27–29 chaetigers; gonopodial papillae in chaetiger 5, small, pale, digitate, 32–34 transverse series of minute papillae per segment).

Description. Syntypes of Brada strelzovi (HDMSU 13.07.1926) complete, whitish, cigar-shaped, fusiform, or slightly swollen anteriorly, tapered posteriorly ( Fig. 18A ); 19–32 mm long, 3–6 mm wide, cephalic cage 1.0– 1.8 mm long (smaller specimens too damaged), 27–36 chaetigers. Papillae free from sediment cover, not forming tubercles, each arising from an oval or polygonal area. Papillae short, digitate, with little sediment, larger dorsally, mostly eroded, in 15–34 transverse series in anterior chaetigers (chaetiger 10), less dense in smaller specimens, smaller ventrally.

Anterior end not observed. Cephalic cage present, chaetae as long as 1/15 body length or 1/3–1 /6 body width. Only chaetiger 1 involved in cephalic cage; chaetae arranged in short lateral series, each with 2–3 chaetae.

Anterior margin of first chaetiger papillated, papillae very short, mostly eroded, abundant. Anterior chaetigers without especially long papillae. Chaetigers 1–3 progressively longer. Chaetal transition from cephalic cage to body chaetae abrupt; aristate neurospines present from chaetiger 2. Ventral gonopodial lobes in chaetiger 5, each rounded, digitate, whitish ( Fig. 18B ).

Parapodia well developed, lateral ( Fig. 18D ). Median neuropodia ventrolateral. Notopodia and neuropodia close to each other. Notopodia with chaetal lobes rounded, short, with 1–2 inferior rounded papillae; neuropodia with larger rounded lobe, with 2–3 inferior rounded papillae.

Median notochaetae arranged in short transverse series, all notochaetae multiarticulate capillaries with articles short basally, medium-sized medially, longer distally ( Fig. 18E ), 5–6 chaetae per bundle, as long as 1/2 body width. Neurochaetae multiarticulate capillaries in chaetiger 1; posterior chaetigers with aristate neurospines, arranged in oblique patterns, 6–7 per bundle. Each neurospine with short rings basally, become shorter medially, distally hyaline, with long aristae ( Fig. 18D , inset).

Posterior end rounded ( Fig. 18C ), pygidium with anus terminal, anal cirri absent.

Remarks. Bradabyssa strelzovi (Jirkov & Filippova in Jirkov, 2001) n. comb. resembles B. alaskensis n. sp. and B. nuda ( Annenkova-Chlopina, 1922) n. comb. in having a large, thick body and first parapodia of similar size tofollowing ones. As indicated above, B. nuda differs from the other two by having gonopodial lobes midventrally displaced. Also, B. strelzovi differs from B. alaskensis in the relative size of neuropodia: they are markedly projecting in B. strelzovi , whereas in B. alaskensis they are barely projecting.

Distribution. Barents Sea, Arctic Ocean, 65–200 m water depth.

Figures

FIGURE 1. Morphological features of Brada Stimpson, 1853, and Bradabyssa Hartman, 1967. A. Brada granulosa Hansen, 1880, lateral view. B. neurochaeta. C. Bradabyssa (olim Trophonia) rugosa (Hansen, 1880) n. comb., lateral view. D. Median parapodium. E. Notochaeta. F. Neurochaeta (modif. after Hansen 1880).

FIGURE 2. Brada granosa Stimpson, 1853. A. Neotype (USNM 1422407), lateral view, anterior end to the right (inset: small paratype, lower right in Fig. 3 A). B. Same, anterior end, ventral view (arrows point to gonopodial lobes). C. Non-type specimen (USNM 22851), head dissected, branchiae and palps removed (Br: branchial scar, PS: palp scar). Scale bars: A: 1.7 mm, B: 1.3 mm, C: 0.4 mm.

FIGURE 3. Brada granosa Stimpson, 1853. A. Juveniles (USNM 453). B. Non-type specimens (USNM 22851), chaetiger 2, right parapodium, anterior view. C. Same, notochaetal basal, medial and distal regions. D. Same, neurochaetal tips. E. Chaetiger 17, right parapodium, anterior view. F. Same, neurochaetal tips. Scale bars: A: 0.8 mm, B, E: 0.3 mm, C: 80 µm, D, F: 20 µm.

FIGURE 18. Bradabyssa strelzovi (Jirkov & Filippova in Jirkov, 2001) n. comb., syntype (HDMSU 13.07.1926). A. Dorsal view, thicker portion is anterior region. B. Anterior end, ventral view (arrows point to gonopodial lobes). C. Posterior end, left lateral view. D. Chaetiger 10, right parapodium, anterior view (insets: neurochaetae). E. Same, basal, medial and distal notochaetal regions. Scale bars: A: 1.5 mm, B: 1 mm, C: 0.7 mm, D: 0.5 mm, E: 40 µm.