Bradabyssa willeyi, 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 : 91-93

Bradabyssa willeyi n. sp.

Figure 48

Material examined. Holotype (BMNH 1923.1.13.1), R.I.M.S. Investigator Expedition, field data unavailable.

Description. Holotype (BMNH 1923.1.13.1), complete, dark-yellow, body soft perhaps rotting when preserved, most neurochaetae broken ( Fig. 48A ); body 43 mm long, 6 mm wide, cephalic cage broken, chaetal length unknown, 55 chaetigers. Dorsal papillae arranged in 8–10 transverse rows, alternating in size ( Fig. 48B ). Each papilla long, with adhering fine sediment particles, forming rounded tubercles.

Anterior end not observed, not dissected to avoid further damage.

Cephalic cage chaetae broken; size relationship to body length or width unknown. Chaetiger 1 apparently involved in cephalic cage; chaetal numbers unknown.

Anterior margin of first chaetiger papillated, papillae smaller than adjacent ones, probably in regeneration.

Chaetigers 1–3 progressively longer. Chaetal transition from cephalic cage to body chaetae abrupt; bases of broken neurospines visible from chaetiger 2. Gonopodial lobes dark, blunt, apparently eroded, in chaetiger 5, and an additional one on left side of chaetiger 6 ( Fig. 48C ).

Parapodia lateral, neuropodia ventrolateral. Parapodial lobes barely developed, chaetae appearing as emerging from body wall ( Fig. 48D ). Notopodial lobe low, with 1–2 inferior papillae, as long as 1/8 notochaetal length; neuropodial lobe slightly more developed, with 2 superior, and 2–3 inferior papillae.

Median notochaetae arranged in transverse row; all notochaetae multiarticulate capillaries, articles short basally, medium-sized medially and subdistally, long distally, 5–6 per bundle, as long as about 1/3 body width. Neurochaetae tapered spines, mostly broken, with very short rings throughout pigmented region, subdistally hyaline, probably aristate ( Fig. 32D , inset).

Posterior region tapered into a blunt cone, terminal segments without papillae, probably eroded ( Fig. 32E ); pygidium depressed, anus flat, ventroterminal, muscular ring, without anal cirri.

Remarks. As indicated in the key above, Bradabyssa willeyi n. sp. resembles B. hartmanae n. sp. because both have notochaetae with basal articles short to medium-sized, and 9–10 transverse rows of dorsal papillae. They differ, however, in the relative density of dorsal papillae and in the pigmentation of gonopodial lobes; in B. “ gangetica ” papillae are distinct individually and gonopodial lobes are darker, whereas in B. hartmanae papillae are laterally fused such that the body wall is not visible, and gonopodial lobes are a similarl colour to the adjacent body wall.

This species is described despite the poor condition of the single specimen, and the lack of complete neurochaetae, which do not allow a complete description. During the R.I.M.S. Investigator expedition (Anonymous 1914), there were two stations labelled off the Ganges Delta, indicating some specimens were found in 193– 405 m. More specimens in good condition are needed to describe it more fully.

Etymology: This species is named after Dr. Arthur Willey. He was Director of the Colombo Museum, Sri Lanka, editor of their journal Spolia Zeylanica, and paid some attention to local fisheries. During this residence, he made some publications dealing with polychaetes and separated the holotype for this species, but did not finish its description.

Distribution. Only known from a single specimen, probably collected off the Ganges delta after the initial naming as gangetica.

Figures

FIGURE 32. Bradabyssa harrisae n. sp. A. Holotype (LACM 9552), right lateral view. B. Paratype (LACM 9553), anterior end, dorsal view. C. Holotype, anterior end, ventral view (arrows point to gonopodial lobes). D. Same, enlarged (arrows point to gonopodial lobes). E. Chaetiger 11, right parapodium, posterior view (inset: neurochaetal tips). Scale bars. A: 1.2 mm, B: 0. 3 mm, C: 0.7 mm, D: 0.2 mm, E: 230 µm.

FIGURE 48. Bradabyssa willeyi n. sp., holotype (BMNH 1923.1.13.1). A. Oblique dorsal view, posterior region twisted. B. Anterior end, dorsal view. C. Anterior end, ventral view (arrows point to gonopodial lobes). D. Mid-body chaetiger, right parapodium, posterior view (inset: close-up of neurochaetae). E. Posterior end, ventral view. Scale bars: A: 1.5 mm, B: 0.8 mm, C: 0.6 mm, D: 0.2 mm, E: 0.4 mm.