Bradabyssa monnioti, 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 : 76-78

Bradabyssa monnioti n. sp.

Figure 39

Type material. Western Indian Ocean . Holotype (MNHN IA-Type 1798), off southwestern Sri Lanka, SAFARI II Cruise, R.V. Marion Dufresne, Sta. 2 (05°40' N, 78°33' E), epibenthic sledge, 3600 m, Jul. 1981 .

Description. Holotype complete (MNHN IA-Type 1798), broken into two pieces ( Fig. 39A ), slightly damaged, integument with three transverse ridges, especially along anterior body half, whitish with dark fine sediment particles remaining basally in lateral papillae. Body cylindrical, blunt anteriorly, tapered posteriorly, 7.8 mm long, 1.3 mm wide, cephalic cage 0.5 mm long, 29 chaetigers. Tunic papillated, papillae sparse (eroded), cylindrical, very long, basally with adherent fine sediment particles. Posterior end papillae very long.

Anterior end not exposed; not dissected to avoid further damage. Cephalic cage chaetae as long as 1/15 body length, or about ¼ body width. Chaetiger 1 involved in cephalic cage; chaetae arranged in short lateral series; 2 notochaetae and 3 neurochaetae per fascicle.

Anterior dorsal margin of first chaetiger papillated, not projecting anteriorly. Chaetigers 1–3 of similar length. Chaetal transition from cephalic cage to body chaetae abrupt; small aristate neurospines present from chaetiger 2. Gonopodial lobes in chaetiger 5.

Parapodia poorly developed, chaetae emerge from body wall ( Fig. 39B ). Parapodia lateral; median neuropodia ventrolateral. Notopodia and neuropodia close to each other; short low conical lobes, neuropodial ones larger.

Median notochaetae in tufts, three per fascicle, all multiarticulate capillaries, articles short basally, poorly defined, longer medially and distally, each article with several rings ( Fig. 39C ); notochaetae (chaetiger 9) slightly longer than body width. Neurochaetae multiarticulate capillaries in chaetiger 1; aristate neurospines from chaetiger 2, short, longer from chaetiger 3, decrease in size posteriorly, 3 neurospines in anterior chaetigers, 4 in median and posterior chaetigers, 1–2 in pre-pygidial segments. Neurospines with very short anchylose articles basally and medially, subdistally hyaline, slightly swollen, straight, aristae long, falcate ( Fig. 39D ).

Posterior end tapered into truncate cone; pygidium with anus terminal; anal cirri absent.

Remarks. Bradabyssa monnioti n. sp. closely resembles B. kirkegaardi n. sp. because both are whitish in colour and their papillae have fine sediment particles adhering basally. They differ due to the relative homogeneity of the body wall surface and the relative size of notochaetal articles: B. monnioti has a rugose body wall with about three transverse ridges per segment, and its notochaetae have long articles each with several annulations, whereas in B. kirkegaardi the body wall is homogeneous, smooth, without any transverse ridge, and notochaetae have long smooth articles.

Etymology. This species in named after the late Dr. Claude Monniot, well-known ascidian specialist, who was in charge of the biological program during the SAFARI cruises (Monniot 1984), during which this and other interesting polychaetes were collected.

Distribution. Off Southwestern Sri Lanka, in 3600 m.

Figures

FIGURE 39. Bradabyssa monnioti n. sp., holotype (MNHN IA-Type 1798). A. Dorsal view. B. Chaetiger 10, left parapodium, anterior view. C. Same, basal, medial and distal notochaetal regions. D. Same, basal, medial and distal neurochaetal regions. Scale bars. A: 0.5 mm, B: 90 µm, C – D: 50 µm.