Bradabyssa antarctica ( Hartman, 1978 ) 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 : 30-32

Bradabyssa antarctica ( Hartman, 1978) n. comb.

Figure 13

Ilyphagus antarcticus Hartman, 1978: 170 –173, Fig. 22a–e .

Type material. Antarctica. Holotype ( USNM 46823 ), USCGC Glacier, Cruise 1, Station 1 (74°07' S, 39°39' W), 650 m, 6 Feb. 1968, J.S. Rankin coll.

Description. Holotype (USNM 46823) complete, pale, cylindrical, tapered towards both ends ( Fig. 13A ); 14 mm long, 1 mm wide, cephalic cage 1.5 mm long, 46 chaetigers, regenerating posteriorly (some parapodia previously removed). Body papillae abundant, rounded short, filiform, capitate, about 6 series per segment in anterior segments, rounded ones less abundant in median and posterior segments (2–3 series per segment), some adherent sediment grains on anterior chaetigers.

Anterior end not exposed; not dissected to prevent further damage. Cephalic cage present, chaetae about as long as 1/10 total length, or 1.5 times longer than body width. Only chaetiger 1 involved in cephalic cage. Cephalic cage chaetae arranged dorsolaterally in short series. Notochaetae and neurochaetae barely separate; 5–6 notochaetae, 3–4 neurochaetae.

Anterior dorsal margin of first chaetiger papillated, slightly depressed; anterior chaetigers without especially long papillae. Chaetigers 1–3 of similar length ( Fig. 13A, B ). Chaetal transition from cephalic cage to body chaetae abrupt; aristate neurospines present from chaetiger 2. Gonopodial lobes not seen.

Parapodia lateral, slightly developed ( Fig. 13D ); 3 large papillae between rami. Median neuropodia ventrolateral. Notopodia and neuropodia close to each other. Notopodia reduced, notochaetae emerge from the body wall; all notochaetae multiarticulate capillaries. Neuropodia better developed, lateral foliose outgrowths, with a few papillae.

Median notochaetae arranged in tufts, multiarticulate capillaries, articles medium-sized basally, long medially and distally; 2–3 in anterior and median chaetigers, 4–5 in posterior chaetigers, 2/3 as long as body width. Neurochaetae aristate spines from chaetiger 2, arranged in transverse series ( Fig. 13D, E ), becoming È-shaped posteriorly, with 2–3 neurospines in anterior chaetigers, 4 in median and posterior ones.

Posterior end tapered, conical ( Fig. 13C ); pygidium with anus dorsal, muscular ring, anal cirri absent.

Remarks. Ilyphagus antarcticus Hartman, 1978 does not belong in Ilyphagus because it lacks a globose body with abundant filiform papillae. The anterior end has not been examined due to the fact that there is only a single holotype specimen, but on the basis of its integument, papillae and neurochaetae it is being transferred to Bradabyssa as a new combination, B. antarctica ( Hartman, 1978) n. comb.

Bradabyssa antarctica resembles B. bransfieldia ( Hartman, 1967) n. comb. by having a cylindrical body. As indicated in the key above, they differ because in B. antarctica anterior dorsal papillae are of a similar size, compared with different sizes as present in B. bransfieldia . Furthermore, in B. antarctica notochaetae are fewer and have medium-sized articles basally, whereas they are more abundant and with short articles basally in B. bransfieldia .

Distribution. Weddell Sea, Antarctica.

Figures

FIGURE 13. Bradabyssa antarctica (Hartman, 1978) n. comb., holotype (USNM 46823). A. Dorsal view. B. Anterior end, dorsal view. C. Posterior end, dorsal view (methyl green staining). D. Chaetiger 7, right parapodium, posterior view. E. Same, neurochaetae. Scale bars: A: 0.7 mm, B, C: 0.2 mm, D: 60 µm, E: 40 µm.

FIGURE 22. Bradabyssa grangieri n. sp. A. Holotype (USNM 1422382), oblique dorsolateral view, most tunic removed. B. Anterior end, oblique dorsal view. C. Anterior end, ventral view (arrows point to gonopodial lobes). D. Posterior end, oblique dorsal view. E. Paratype (USNM 1422383), head, frontal view, palps and branchiae removed (Br: branchial scars, PS: palp scar). F. Same, chaetiger 10, right parapodium, basal, medial and distal notochaetal regions. G. Same, aristate neurospines, one with a subdistal constriction. H. Non-type specimen (USNM 1422385), chaetiger 10, right parapodium, typical neurospine tips. Scale bars: A: 5.3 mm, B: 1.1 mm, C: 1 mm, D: 1.2 mm, E: 0.9 mm, F: 60 µm, G, H: 120 µm.