Brada granulosa Hansen 1880

Brada granulosa Hansen, 1880 Figure 4 Brada granulosa Hansen, 1880: 229 –230, Pl. 5, Figs 4–6.— Hansen 1882: 39, Pl. 7, Figs 21–22.— Fauvel 1914: 238, Pl. 21, Figs 10–12.— Støp-Bowitz 1948a: 47 –50, Fig. 13 (syn.).— Støp-Bowitz 1948b: 46 –47, map.— Jirkov & Filippova 2001: 352, Figs 1–4.— Oug et al. 2011: 15, unnumb. figs a–c (repeated from Støp-Bowitz, 1948a).— Moore 1909a: 143. (non Malmgren, 1867). Brada normani McIntosh, 1908: 543 –544, Pl. 12, Figs 4, 5, Pl. 12A, Fig. 10. Type material. Northwestern European Arctic Ocean. Four syntypes (ZMUB 2196), partially dehydrated, damaged, Norwegian North Atlantic Expedition, Sta. 275 (74°08' N, 31°12' E), 269 m, greenish clay, 1877 (26–35 mm long, 7–9 mm wide, cephalic cage 1 mm long (only one neurochaetae left in one specimen), 23–25 chaetigers). Four complete syntypes (ZMUB 2197), and fragments of 3 others, Norwegian North Atlantic Expedition, in two stations: 337 (76°23' N, 16°43' E), off southernmost point of Spitzbergen, Norway, no depth data, and 370 (78°48' N, 08°37' E), off the westernmost point of Spitzbergen, Norway, about 915 m, 1877 (largest used for redescription, others 22–31 mm long, 9.5–12 mm wide, cephalic cage 0.5–1.0 mm long, 22–23 chaetigers; one anterior fragment had ripe ovaries with eggs about 200 µm). Additional material. Five specimens (ZMUB 26383), Voringen, Sta. 267 (no further data) (13–41 mm long, 4.5–9.0 mm wide, cephalic cage 0.5 mm long, 22–24 chaetigers). Two specimens (ANSP 2853), off Fish Island, outside of Hebron, Labrador, Canada, 137 m, mud, 25 Aug. 1908, O. Bryant, coll. (38–44 mm long, 10 mm wide, cephalic cage 0.9–1.0 mm long, 24 chaetigers; gonopodial lobe in chaetiger 4). Description. Largest syntype (ZMUB 2197) complete, brownish, slightly damaged (Fig. 4A). Body fusiform, blunt at both ends; 36 mm long, 12 mm wide, cephalic cage 1 mm long, 21 chaetigers. Papillae long, conical, mucronate, mucron capitate, larger dorsally, shorter ventrally; arranged in 6–7 alternating transverse series dorsally, 4–5 ventrally; all papillae with large sediment particles, forming large tubercles in first few chaetigers, particularly close to chaetal lobes (more visible in larger syntypes). Anterior end observed by dissection in an anterior fragment (ZMUB 2197). Prostomium low, dark-gray, with some black spots (Fig. 4C). Eyes not seen. Caruncle wide basally, extended posteriorly, not reaching branchial plate margin. Palps dark gray; palp keels rounded, slightly darker. Lips darker; lateral lips thick, well developed; ventral lip reduced. Dorsal lip darker, triangular, clearly separated from lateral lips. Branchiae thick cirriform, sessile on branchial plate, arranged in a single marginal row, filaments separated into two lateral groups, each with 4 filaments. Largest branchiae as long as, and slightly thinner than palps. Nephridial lobes on branchial plate not seen. Cephalic cage chaetae as long as 1/36 of body length, or 1/12 as long as body width. Chaetiger 1 with 1–2 thin chaetae per ramus, arranged in short lateral series. Anterior dorsal margin of first chaetiger triangular, papillated. Anterior chaetigers without especially long papillae; in larger specimens (ANSP 2853) with fused tubercles forming a sandy crust. Chaetigers 1–3 gradually decrease in size. Chaetal transition from cephalic cage to body chaetae abrupt, with curved anchylose neurospines from chaetiger 2. Gonopodial lobes present in chaetiger 4, short, digitate, grayish (Fig. 4B). Parapodia well developed, lateral; median neuropodia ventrolateral (Fig. 4D). Notopodia and neuropodia close to each other. Notopodia digitate thin lobes, covered by thin layer of sediment particles, surrounded by larger papillae. Neuropodia larger, truncate conical lobes, covered by thin layer of sediment, with about 3 pre- and 2 postchaetal papillae, much larger than neurochaetal lobe. All notochaetae multiarticulate capillaries; median notochaetae arranged in short series, 2 chaetae per ramus, one with short articles basally, becoming longer medially and even longer distally, the other with very long articles, increasing in length distally (Fig. 4E). Notochaetae as long as 1/5–1/6 body width. Neurochaetae multiarticulate capillaries in chaetiger 1. Falcate, subdistally expanded blunt neurospines from chaetiger 2, arranged in oblique series, 5–6 per bundle, tips falcate (Fig. 4F), more pronounced in median and posterior chaetigers (Fig. 4G). Tips appearing hooded (Fig. 4G, inset). Posterior end globose, pygidium with anus terminal, as a vertical slit; anal cirri absent. Variation. Adult specimens 13–44 mm long, 9.5–12.0 mm wide, 22–24 chaetigers. Remarks. Brada granulosa Hansen, 1880 and B. granosa Stimpson, 1853 are very similar because, in both, dorsolateral papillae are fused forming transverse series of sandy tubercles. However, they differ by the relative shape of neurochaetae and pattern of ventral papillae: in B. granulosa neurochaetae are more falcate, with wide, blunt tips, and ventral papillae are of a similar size, whereas in B. granosa neurochaetae are less falcate, with tapered tips, and ventral papillae alternate in size. Also, B. normani McIntosh, 1908 was regarded as a junior synonym of B. inhabilis (Rathke, 1843) by Haase (1915: 177, 206), and by Støp-Bowitz (1948a:40), who also included McIntosh (1908) in Remarks but failed to list B. normani in the synonymy. Despite McIntosh’s (1908) short description, the illustrations support the case for B. normani being regarded as a junior synonym of B. granulosa because the dorsal papillae are long and tapered, and neurochaetal tips are wide. Herein B. normani is regarded as a junior synonym of B. granulosa. Distribution. Arctic and subarctic environments, reaching about 1000 m depth.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.