Bradabyssa setosa (Verrill, 1873) 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 : 84-85

Bradabyssa setosa (Verrill, 1873) n. comb.

Figure 43

Brada setosa Verrill, 1873: 606 (Verrill 1874: 312) , no figs.—Verrill 1881: 302, Pl. 9, Fig. 4 .—Hartman 1944: 341, Pl. 33(58), Fig. 13 .

Type material. Northwestern Atlantic. Holotype of Brada setosa ( USNM 14537 ), off Gay Head (41°20'59" N, 70°50'15" W), Duke Island, Mass., U.S.A., 10–18 m, 1871, A. E. Verrill, coll.

Additional material. Northwestern Atlantic. Four specimens ( ANSP 1379 ), all complete, slightly damaged, Buzzards Bay , Mass., R.V. Fish Hawk, Sta. 7656, 57, 10–16 m, sandy mud , J.P. Moore, coll. (7.0– 8.5 mm long, 1–2 mm wide, cephalic cage 1 mm long, 23–28 chaetigers; larger one previously ventrally dissected, anterior end removed). One specimen ( ANSP 1399 ), Buzzards Bay , Mass., 1904, no further data (18.5 mm long, 3 mm wide, cephalic cage 1.5 mm long, 23 chaetigers; previously dorsally dissected). Anterior fragment ( ANSP 2654 ), Woods Hole, Mass. , USFC, R.V. Phalarope dredgings, survey 165, 1907, no further data (dissected to observe anterior end; too macerated to provide details; papillae of chaetiger 20). Eight specimens (USNM 14541), three complete, many chaetae broken, R.V. Fish Hawk, off Halfway Rock, Sta. 803, 37 m, 16 Aug. 1880, A.E. Verrill, coll., id. (11–18 mm long, 1.5–2.9 mm wide, cephalic cage 0.5–1.0 mm long, 30–32 chaetigers). One specimen (USNM 14544), many chaetae broken, R.V. Speedwell, NW arm Halifax Harbor, Sta. 90-1, 12 m, 11 Sep. 1877, A.E. Verrill, coll., id. (17 mm long, 2.5 mm wide, cephalic cage broken, 29 chaetigers). One specimen ( USNM 48462 ), Cape Cod Bay, Mass., Sta. 2322-5, 16– 21 m, 11 May 1966 , C.D. Long, coll. (25 mm long, 4.5 mm wide, cephalic cage 3 mm long, 33 chaetigers; anterior end slightly exposed).

Description. Holotype (USNM 14537) slightly damaged, most chaetae broken; body with parallel sides (ANSP-1399 slightly swollen medially), dark with adhering yellow sediment, posterior end damaged ( Fig. 43A ); 8 mm long, 2 mm wide, cephalic cage chaetae not seen, 17 chaetigers. Papillae cirriform to fusiform, basally swollen, tips truncate, rounded, slightly capitate, arranged in 5–6 transverse series of similar sized papillae, alternating in their position, completely covered by sediment.

Anterior end not exposed; holotype not dissected to avoid further damage (other specimens too damaged; multiple short branchiae and large palps visible). Cephalic cage broken (ANSP1399 with 4–5 notochaetae and 2–3 neurochaetae per side).

Anterior dorsal margin of first chaetiger papillated, papillae large, rounded. Chaetigers 1–3 of similar size. Chaetal transition abrupt; aristate neurospines present from chaetiger 2. Gonopodial lobes in chaetiger 5 ( Fig. 43B ).

Parapodia well developed, lateral. Median neuropodia ventrolateral. Notopodia and neuropodia close to each other. Notopodia with 2–3 bottle-shaped papillae, each completely covered by sediment (ANSP 1399 with papillae as long as 1/4 notochaetal length). Neuropodia muscular projected truncate cone, with 6–8 marginal bottle-shaped papillae.

Median notochaetae arranged in short transverse series ( Fig. 43C ). Notochaetae all missing from holotype (ANSP 1399 with multiarticulate capillaries, articles medium-sized basally, longer medially and distally ( Fig. 44D ), 4–5 per bundle, as long as ½ body width). Neurochaetae multiarticulate capillaries in chaetiger 1 (ANSP 1399); aristate neurospines from chaetiger 2, arranged in oblique series, 3–5 per ramus; each neurospine with short rings basally, decreasing in size medially, distally hyaline, with long, delictate aristae ( Fig. 43E , inset).

Posterior end missing from holotype (ANSP 1379 with posterior end tapered into rounded lobe; pygidium with anus ventroterminal, with smaller papillae, anal cirri absent; one small specimen with an anal lobe, middorsal narrow, rounded, ventrally directed).

Remarks. Bradabyssa setosa (Verrill, 1873) n. comb. groups with other species with 28–33 chaetigers and pale gonopodial papillae such as B. pluribranchiata (Moore, 1923) n. comb., and an undescribed species from Brazil. However, B. setosa differs from B. pluribranchiata because the former has large sediment particles on papillae and longer hyaline areas in neurochaetal tips, whereas on B. pluribranchiata there are fine sediment particles adhering to dorsal papillae, and hyaline areas of the neurospines are shorter.

Verrill illustrated his species (1881:302, Pl. 9, Fig. 4 ), and this was later reproduced by Hartman (1944:341, Pl. 33(58), Fig. 13 ). The illustration shows a subcylindrical, posteriorly incomplete specimen, with over 30 chaetigers and it is obviously not the holotype as eventually designated.; it might be thought that the holotype was alive and exposing its anterior end, but because the holotype has only 17 chaetigers, it is enigmatic what happened to the illustrated specimen, and why it was not chosen as the type.

Pettibone (1954:290–291) regarded a number of species including B. setosa as junior synonyms of B. villosa (Rathke, 1843) , but she did not examine any specimens of the latter. Furthermore, after examining the type material of B. pilosa , B. pluribranchiata , and B. setosa , she concluded that (p. 291) “… there may be varying numbers of papillae as well as all gradations in the amount of encrusting sand grains.”. Her observation was indeed correct, but these differences in papillae number and relative size are consistent and may be used to distinguish these similar species. Blake (2000:6–7) followed Pettibone and attributed the variation in sand cover to ontogeny, although he stated that (p. 7): “… sand accumulation and abrasion have a steady and cumulative effect on the body surface …” However, after examination of type and non-type specimens from different sizes for many species, I have concluded that although integument abrasion and papillae increase in size in larger specimens is correct, the relative papillar size, shape and amount of sand cover remain consistent within a species (see key above). Therefore, former synonymies should be regarded as questionable and not justified, as they fail to provide enough detail for these conclusions.

Distribution. Northwestern Atlantic Ocean, off Massachusetts, USA, in shallow water..

Figures

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 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 43. Bradabyssa setosa (Verrill, 1873), n. comb., holotype (USNM 14537): A. Right lateral view, anterior end at right. B. Anterior region, ventral view (arrows point to gonopodial lobes). Non-type specimen (ANSP 1399): C. Chaetiger 19, right notopodium. D. Same, basal (with covering cuticle), medial and distal notochaetal regions. E. Same, right neuropodium (inset: close-up of neurochaetae). Scale bars. A: 0.6 mm, B: 0.7 mm, C: 0.2 mm, D: 50 µm, E: 0.3 mm.

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.