Brada granosa Stimpson, 1853

Salazar-Vallejo, Sergio I., 2017, Revision of Brada Stimpson, 1853, and Bradabyssa Hartman, 1967 (Annelida, Flabelligeridae), Zootaxa 4343 (1), pp. 1-98 : 10-12

Brada granosa Stimpson, 1853

Figures 2 , 3

Brada granosa Stimpson, 1853: 32 .— Webster & Benedict 1887: 732, Pl. 5, Figs 72–76.— Pettibone 1956: 565.— Appy et al. 1980: 34, Fig. 63.

Type material. Northwestern Atlantic Ocean. Neotype ( USNM 1422407 ), and six juveniles, Union College Zoological Expedition, Eastport, Maine, 1880 , H.E. Webster, coll. (juveniles ( USNM 453 ) 1.5–3.0 mm long, 0.5–1.0 mm wide, 13–17 chaetigers ).

Additional material. Northwestern Atlantic Ocean . Six specimens ( USNM 14525 ), Whiting River , Bay of Fundy , 1872 (10–17 mm long, 3.8–5.0 mm wide, 22–24 chaetigers; gonopodial lobes in chaetiger 4). One specimen ( USNM 14531 ), Bay of Fundy , 1872 (17 mm long, 4.5 mm wide, chaetiger 1 with 2 chaetae per fascicle, 0.6 mm long, 24 chaetigers). Thirteen specimens ( USNM 22851 ), R.V. Blue Dolphin, Sta. 27 (58°11.4' N, 62°34.2' W), off Okak Bay, Labrador, 174 m, 8 Aug. 1949, D.C. Nutt, coll. (40–52 mm long, 9–10 mm wide, 20–25 chaetigers; gonopodial lobes in chaetiger 4; 5–8 alternating transverse series of papillae in chaetiger 5). One specimen ( MCZ 2435 ), Portland Harbor, Maine, 24 Sep. 1873, no further data (12 mm long, 4 mm wide, 24 chaetigers, gonopodial lobes in chaetiger 4).

Description. Neotype (USNM 1422407) fusiform, blunt in both ends ( Fig. 2A ); 31 mm long, 7.5 mm wide, no cephalic cage, 22 chaetigers. Body papillate; papillae with abundant, cemented sand grains, forming large elevated tubercles dorsally, extending laterally to slightly below neuropodial bases, often fused to each other and forming 2–3 series per segment; ventral papillae roughly similar-sized, forming smaller rounded tubercles, arranged in 5–6 transverse series. Papillae with thick cylindrical stems, mucronate, tip long.

Anterior end modifications based on another specimen (USNM 22851). Cephalic hood not exposed, short, margin smooth. Prostomium low cone, apparently without eyes. Caruncle projected posteriorly, not dividing branchial plate. Palps massive; palp keels low, rounded, fused. Lateral lips well developed. Ventral lip reduced; dorsal lip rounded, short.

Branchiae cirriform, thick, sessile on branchial plate ( Fig. 2C ), each with a foliose rounded basal membrane, interlocked by penetrating its inferior margin; arranged in a single series, 8 filaments, each about as thick as, and as long as palps. Nephridial lobes not seen in branchial plate.

Cephalic cage absent. Anterior dorsal margin of first chaetiger papillated. Anterior chaetigers without especially long papillae. Chaetigers 1–3 of similar size. Neurochaetae cylindrical, distally foliose, curved spines present from chaetiger 2. Gonopodial lobes in chaetiger 4 ( Fig. 2B ); rounded, with rugose darker cap.

Parapodia poorly developed; chaetae emerge from body wall ( Fig. 3B ), more projected in median and posterior chaetigers ( Fig. 3E ). Parapodia lateral; median neuropodia ventrolateral. Notopodia and neuropodia close to each other. Notopodia without chaetal lobes, one papilla inferior to notochaetae, bifid (two tips); neuropodia projected as chaetal lobes, one papilla inferior to neurochaetae, with two (rarely 3) tips; some neuropodia with papillae series fused, sometimes forming 1–2 concentric laminar lobes in frontal view.

Median notochaetae arranged in short transverse series; all multiarticulate capillaries with short arcticles basally, longer medially and distally ( Fig. 3C ), 2–3 per bundle, as long as 1/3–1/4 body width. Neurochaetae all anchylose, brownish spines, present from chaetiger 2, arranged in transverse series, tapered, 1–3 in chaetigers 1–4 ( Fig. 3D ), then blunt, 6–7 throughout the body. All neurospines falcate, more falcate in median and posterior chaetigers ( Fig. 3F ); each with short anchylose articles basally and medially, then paler in foliose portion, distally blunt.

Posterior end tapered, blunt cone; pygidium with anus terminal, between two lateral rounded cushions.

Variation. Juveniles 1.5–3.0 mm long, 0.5–1.0 mm wide, 13–17 chaetigers; adults 10–17 mm long, 3.8–5.0 mm wide, 22–24 chaetigers. In juveniles ( Fig. 3A ) chaetiger 1 has very short, tapered thin, fragile neurospines. Neurochaetae are all anchylose, medially expanded spines, distal part flexible, longer in juveniles. Three juveniles had an anal tube made with cemented grains adhered over the outer cover. It is noteworthy that juveniles as long as about 1/ 10 adult size, already have almost all body chaetigers; it seems that chaetiger number becomes fixed very early in development, and then growth is mostly in segment size, with little growth in segment number.

Remarks. Brada granosa Stimpson, 1853 and B. granulosa Hansen, 1880 resemble each other by having transverse sandy tubercles, made by at least their dorsolateral papillae. There is a similar development of dorsal ridges encrusted with sediment, and they can be mounted on separate series of papillae, fuse two out of three rows, or fuse all the three rows, but chaetal features separate them. In B. granosa neurochaetae are less falcate, with tapered tips, and ventral papillae alternate in size, whereas in B. granulosa they are more falcate, with wide, blunt tips, and ventral papillae are of a similar size.

The original description of Brada granosa by Stimpson is brief, of specimens collected off Grand Manan Island, Bay of Fundy in the northeastern Atlantic Ocean, it and only includes a short implicit comparison with another northeastern Atlantic species, B. sublaevis Stimpson, 1853 .

However , the original type material was destroyed after it was deposited in the Smithsonian Institution but later transferred to Chicago when William Stimpson was appointed director of the local Academy of Sciences in 1866; regretfully, his collections were destroyed during the great Chicago 1871 fire (http://www.si.edu/oahp/ ScientificIllustrators /WStimpson.html, including many type specimens he had designated. Therefore, in order to clarify the taxonomic status of this species, a neotype for Brada granosa is herein proposed as it is also the type species for Brada.

The species was briefly redescribed by Webster & Benedict (1887), from some specimens which included juveniles and a single adult, and which were collected off Eastport, Maine, northeastern Atlantic Ocean , in 1880, very close to the original type locality in the Bay of Fundy. Other specimens of B. granosa have been confidently identified and recorded from the type locality and other localities along the northeastern coast of North America. The adult from Webster & Benedict’s (1887) description was selected as the neotype, as it agrees well with the Stimpson’s original description as well (however brief), it and has been deposited in the National Museum of Natural History, Smithsonian Institution.

The neotype was selected, described and illustrated to clarify the taxonomic status of the species (ICZN 1999, Art. 75.3.1–75.3.3). The type material was deposited in the Smithsonian Institution but later transferred to Chicago when William Stimpson was appointed director of the local Academy of Sciences in 1866; regretfully, as indicated above, his collections were destroyed. Despite the fact that the original description was brief, B. granosa has been confidently identified and recorded in the type locality, and the neotype corresponds to the species (ICZN 1999, Art. 75.3.5). The proposed neotype was collected in Eastport, Maine, nearby Grand Manan, mouth of the Bay of Fundy, which was the type locality (ICZN 1999, Art. 75.3.6), and as indicated above, it has been deposited in the National Museum of Natural History, Smithsonian Institution (ICZN 1999, Art. 75.3.7).

Distribution. In shallow depths to 200 m along the northeastern coast of North America.

Figures

FIGURE 2. Brada granosa Stimpson, 1853. A. Neotype (USNM 1422407), lateral view, anterior end to the right (inset: small paratype, lower right in Fig. 3 A). B. Same, anterior end, ventral view (arrows point to gonopodial lobes). C. Non-type specimen (USNM 22851), head dissected, branchiae and palps removed (Br: branchial scar, PS: palp scar). Scale bars: A: 1.7 mm, B: 1.3 mm, C: 0.4 mm.

FIGURE 3. Brada granosa Stimpson, 1853. A. Juveniles (USNM 453). B. Non-type specimens (USNM 22851), chaetiger 2, right parapodium, anterior view. C. Same, notochaetal basal, medial and distal regions. D. Same, neurochaetal tips. E. Chaetiger 17, right parapodium, anterior view. F. Same, neurochaetal tips. Scale bars: A: 0.8 mm, B, E: 0.3 mm, C: 80 µm, D, F: 20 µm.