Bradabyssa tzetlini (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 : 85-87

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

Figure 44

Brada tzetlini Jirkov & Filippova, 2001: 356 –357, Figs 1–5 .—Oug et al. 2011: 14, Figs 1–4 (reprod. from Jirkov & Filippova, 2001).

Type material. Norwegian Sea. Syntype (HDMSU 21.07.1957), R.V. Sevastopol, Cruise 5, Sta. 1116 (63.0° N, 02.25° E), 950 m, 21 Aug. 1957. Syntype (HDMSU 27.09.1958), dried-out, R.V. Sevastopol, Cruise 10, Sta. 1702 (66.38° N, 04.59° E), 1125 m, 27 Sep. 1958 (cephalic cage 1.5 mm long, 2 notochaetae and 2 neurochaetae in chaetiger 1). Syntype (HDMSU 15.10.1958), R.V. Sevastopol, Cruise 10, Sta. 1766 (65.13° N, 00.10° E), 730 m, 15 Oct. 1958, Agassiz trawl (two anterior fragments of mature females, partly dehydrated; oocytes about 125 µm). Syntype (HDMSU 4.11.1959), dried-out, R.V. Sevastopol, Cruise 15, Sta. 2444 (69.2° N, 00.08° E), 1000 m, 4 Nov. 1959 (parapodia with 4 notochaetae and 4 neurochaetae per ramus). Syntype (HDMSU 30.06.1978), R.V. Tunetz, Cruise 105, Sta. 16 (72.5° N, 00.14° E), 960 m, 30 Jun. 1978 (complete, slightly swollen anteriorly, 13 mm long, 3 mm wide, cephalic cage 2 mm long (5 notochaetae, 4 neurochaetae), 30 chaetigers, gonopodial lobes in chaetiger 5, each digitate with tip black, posterior end with anus dorsal, anus with a thick black muscular ring, without anal cirri. Notochaetae 4–5, in transverse series, neurochaetae 4–5, in oblique series; notochaetae about 1/3 as long as body width, 5 transverse series of dorsal papillae).

Description. Better preserved syntype (HDMSU 21.07.1957) broken in two fragments; body whitish, papillae light brown ( Fig. 44A ), ventrally flat, blunt at both ends; 24(11+13) mm long, 4 mm wide, cephalic cage 1.8 mm long, 34(13+21) chaetigers. Papillae covered by fine sediment grains. Papillae very long, larger dorsally, arranged in 5–6 transverse series, shorter ventrally ( Fig. 44B ); posterior chaetigers with larger papillae, basally swollen, globular with long tip. Smaller syntype (HDMSU 30.06.1978) 13 mm long, 3 mm wide, cephalic cage 2 mm long, 30 chaetigers.

Anterior end not dissected. Cephalic cage chaetae broken; in another syntype (HDMSU 30.06.1978) chaetae 2.0 mm long. Only chaetiger 1 involved in cephalic cage; chaetae arranged in short lateral series, with 5 notochaetae and 4 neurochaetae per bundle.

Anterior margin of first chaetiger papillated, papillae short, rounded, eroded. Anterior chaetigers without especially long papillae. Chaetal transition from cephalic cage to body chaetae abrupt; aristate neurospines present from chaetiger 2. Gonopodial lobes in chaetiger 5 ( Fig. 44B, C ), blunt, digitate, tip slightly darker.

Parapodia well developed, lateral ( Fig. 44D ). Median neuropodia ventrolateral. Notopodia and neuropodia close to each other. Notopodia with chaetal lobe short, rounded, with 3–4 long papillae, longest about 1/3 as long as notochaetae.

Median notochaetae arranged in short transverse series, most notochaetae multiarticulate capillaries with articles short basally and medially, become long distally ( Fig. 44E ); about 4–5 notochaetae per bundle, about half as long as body width. Neurochaetae multiarticulate capillaries in chaetiger 1; posterior chaetigers with aristate neurospines, arranged in short transverse series, 4 per bundle. Each neurospine with short rings basally and medially, distally tapering, hyaline with long falcate mucro ( Fig. 44F ).

Posterior end rounded, truncate; pygidium with anus terminal, thick, anal cirri absent. Oocytes in a mature anterior fragment (HDMSU 15.10.1958), about 125 µm.

Remarks. Bradabyssa tzetlini (Jirkov & Filippova in Jirkov, 2001) n. comb. belongs to a group of species having 28–33 chaetigers and dorsal papillae with adhering sand particles, which includes B. pluribranchiata (Moore, 1923) n. comb. and B. setosa (Verrill, 1873) n. comb. However, B. tzetlini differs from these other species by having gonopodial papillae with pale stems and dark tips, whereas the other species possess completely pale ones.

Distribution. Scandinavian waters, Norwegian Sea, in 700–1200 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 4. Brada granulosa Hansen, 1880, syntypes (ZMUB 2197). A. Largest and smallest syntypes, oblique lateral view, anterior end pointing upwards. B. Largest syntype, anterior end, lateral view (arrow points to gonopodial lobe). C. Another syntype, head, frontal view, branchiae and palps removed (Br: branchial scar, PS: palp scar). D. Same, chaetiger 10, right parapodium, posterior view. E. Same, basal, medial and distal notochaetal regions. F. Chaetiger 3, right parapodium, neurochaetae tips (insets: chaetal tips). G. Chaetiger 11, neurochaetae (inset: chaetal tip). Scale bars: A: 6 mm, B: 0.7 mm, C: 0.5 mm, D: 0.1 mm, E: 40 µm, F: 0.2 mm, G: 110 µm.

FIGURE 5. Brada incrustata Støp-Bowitz, 1948. A. Lectotype (ZMUB 18605), right lateral view, anterior end above. B.

FIGURE 44. Bradabyssa tzetlini (Jirkov & Filippova in Jirkov, 2001) n. comb., syntype (HDMSU 21.07.1957): A. Anterior region, dorsal view. B. Same, right lateral view (arrow points to gonopodial papilla). C. Same, ventral view (arrows point to gonopodial papillae). D. Same, chaetiger 13, right parapodium. E. Same, basal, medial and distal notochaetal regions. F. Same, basal, medial and distal neurochaetal regions. Scale bars. A: 1.1 mm, B: 0.7 mm, C: 1 mm, D: 0.2 mm, E: 80 µm, F: 80 µm.