Bradabyssa mammillata Salazar-Vallejo 2017, n. comb.

Bradabyssa mammillata (Grube, 1877) n. comb.

Figure 26

Brada mammillata Grube, 1877a: 69, 1877b: 541.—McIntosh 1885: 370–371, Pl. 43, Fig. 11, Pl. 23A, Figs 7, 8.—Ehlers 1897: 109.—Fauvel 1932: 185–186, 1953: 352.—Monro 1939: 131.—Hartman 1953: 51.—Hartman 1966: 33 Pl. 9, Figs 3, 4.—Hartman 1967: 122.—Wiktor 1980: 277.—Rozbaczylo 1985: 158.— Hartwich 1993: 116.

Type material. Southern Indian Ocean. Kerguelen Islands. One syntype (MNHW 264), Successful Bay, (Kerguelen Islands in Grube 1877b:511), R.V. Gazelle, Schleinitz or Buchholz, coll. (damaged, most larger papillae eroded, body wall ventrally broken by chaetigers 5–8; 50 mm long, 6.5 mm wide, cephalic cage 4 mm long, 31 chaetigers). Four syntypes (ZMB 688), complete, Whale Bay, R.V. Gazelle, Schleinitz or Buchholz coll. (10–67 mm long, 4.5–10.0 mm wide, cephalic cage 2–5 mm long, 27–30 chaetigers). Two syntypes (ZMB 689), off Mount Campbell, R.V. Gazelle, Schleinitz or Buchholz coll. (complete syntype 51 mm long, 8 mm wide, cephalic cage 3 mm long, 29 chaetigers; tubercles large, rounded, arranged in 3 transverse series, anterior ones closer to each other, median series with larger tubercles; larger dorsal tubercles arranged in 4 longitudinal series; ventral papillae much smaller, arranged in 5 transverse series with alternating papillae in successive rows).

Additional material. Southern Indian Ocean. Kerguelen Islands. Three specimens (MNHN 186), complete, 16–18 Jan. 1909, Rallier du Baty, coll. (50–70 mm long, 7.5–12.0 mm wide, cephalic cage 6–7 mm long, 28–30 chaetigers). Three specimens (MNHN 186a), complete, R.V. Curieuse, C-22, 1914, Rallier du Baty & Soranchet, coll. (one mature female with anterior end exposed; 42.0– 67.5 mm long, 7.5–12.0 mm wide, cephalic cage 4–6 mm long, 30 chaetigers; oocytes 150–200 µm). Five specimens (MNHN-354), only one juvenile complete, with anterior end exposed, Morbihan Bay, 25 Sep. 1951, P. Paulian, coll. (22 mm long, 5 mm wide, cephalic cage 3 mm long, 26 chaetigers). Two specimens (USNM 4828), R.V. Challenger, Sta. 149, Betsy Cove, 46–55 m (most larger tubercles eroded; one with a longitudinal dissection and most viscerae removed; not dissected specimen 67 mm long, 10 mm wide, cephalic cage 1 mm long, 28 chaetigers; gonopodial lobes in chaetiger 5). Antarctica. One specimen (USNM 56658), damaged, USNS Eltanin, Bransfield Strait, Sta. 432 (62°52' S, 59°27' W), 935– 884 m, 7 Jan, 1963 (60 mm long, 6 mm wide, cephalic cage 3 mm long, 30 chaetigers; gonopodial lobes in chaetiger 5). One specimen (USNM 56664), damaged, off South Orkney Island, USNS Eltanin, Sta. 1078 (61°27' S, 41°55' W), 604 m, 12 Apr. 1964. One specimen (LACM 9550), off South Orkney Island, USNS Eltanin, Sta. 1079 (61°26'S, 41°55' W → 61°24' S, 41°55' W), 593–598 m, 13 Apr. 1964. Two specimens (USNM 56665), off South Orkney Island, USNS Eltanin, Sta. 1079 (61°26' S, 41°55' W), 593–598 m, 13 Apr. 1964 (43–101 mm long, 8–11 mm wide, cephalic cage 3 mm long, 31–35 chaetigers; gonopodial lobes in chaetiger 5).

Description. Syntypes (ZMB 689) fusiform, oval in cross section, incurved, slightly to markedly narrower posteriorly (Fig. 26A); up to 67 mm long (USNM 56665, 101 mm long), 4.5–10 mm wide, cephalic cage 2–5 mm long (other specimens with chaetae broken), 27–30 chaetigers (USNM 56664, 36 chaetigers). Dorsal tubercles large, globular, in three transverse series per chaetiger, middle series with 5–6 larger, stiff, other series with tubercles less than half as large (Fig. 26B); ventral papillae in three rows, rounded (eroded in several syntypes); without tunic, sediment grains adherent to papillae and body tegument.

Cephalic hood not exposed. Anterior end observed by dissection and in non-type specimen (MNHN 186). Prostomium low cone, anterior eyes poorly defined; posterior ones in low rounded lobes. Caruncle extended posteriorly separating branchial plate, median keel pale, lateral ridges dark (Fig. 26D). Palps folded; palp keels well developed, rounded.

Branchiae cirriform, sessile on branchial plate, arranged in irregular rows, over 100 per lateral group, some filaments longer than palps. Lateral lips well developed, thick; dorsal lip pigmented, reduced; ventral lip not seen. Nephridial lobes distinct, pale brown, tubular, separated from branchial plate.

Cephalic cage chaetae as long as 1/5–½ body width; chaetae of chaetigers 1–3 slightly longer, directed forward. Chaetae arranged in short lateral series, about 6 capillary chaetae per ramus.

Anterior dorsal margin of first chaetiger with two large rounded papillae. Chaetigers 1–3 of similar length, parapodial development similar. Chaetal transition from cephalic cage to body chaetae abrupt; aristate neurospines present from chaetiger 2. Gonopodial lobes black, in chaetiger 5 (Fig. 26C, one syntype with a small accessory papilla in chaetiger 6).

Parapodia well developed, lateral. Median neuropodia ventrolateral. Notopodia and neuropodia close to each other. Notopodia less developed than neuropodia, anterior chaetigers with a large trifid rounded infrachaetal papilla, median chaetigers with papillae bifid, posterior chaetigers with single rounded or no infrachaetal papilla. Neuropodia projecting rounded lobes, 3–4 rounded marginal papillae.

Median notochaetae arranged in longitudinal short series; all notochaetae multiarticulate capillaries, most chaetae with short articles basally and medially, medium-sized or long distally, one chaetae with long articles basally (Fig. 26E), 4–6 per ramus, 1/6 as long as body width. Aristate neurospines from chaetiger 2, most broken, arranged in J-shaped patterns, 4–5 per ramus (Fig. 26F); neurochaetae with very short rings, tips broken, visible in juvenile or smaller specimens (Fig. 26G).

Posterior end tapered; pygidium blunt cone, anus terminal, anal cirri absent.

Variation. The different size ranges in the type material shows that the tough body, provided with large globular dorsal tubercles, is a stable feature. The shortest syntype (ZMB-688) is 10 mm long, and shows these features, even though it was fixed in alcohol. Syntypes were 10–67 mm long, 4.5–10.0 mm wide, cephalic cage 2–5 mm long, 27–31 chaetigers. Additional specimens 22–101 mm long, 5–12 mm wide, cephalic cage 3–7 mm long, 26–35 chaetigers.

Remarks. Bradabyssa mammillata (Grube, 1877) n. comb. resembles B. verrucosa (Chamberlin, 1919) n. comb. by having tubercles of different sizes. They differ because B. mammillata has chaetigers 1–3 equally developed whereas in B. verrucosa chaetiger 2 projects more than surrounding chaetigers. One specimen (MNHN 186) has long, pale tubular epibionts; others contain oocytes.

Bradabyssa mammillata also resembles B. elinae by having a single series of larger globular tubercles per segment; however, they differ because B. mammillata has a stiff, wider body, whereas B. elinae is thinner and softer, and because in B. mammillata the anchylose, aristate neurospines have very short rings, whereas in B. elinae they are medium-sized.

Wehe & Fiege (2002:48) stated that there was no type locality indicated for this species; however, the type locality was indicated in the original publication (Grube 1877a:69). The records for the Arabian of Persian Gulf by Wesenberg-Lund (1949:334–335), or from Japan by Imajima (1964:246–247, Figs. 33–38), are questionable.

Distribution. Antarctic Ocean and nearby localities, in moderate to abyssal depths.