Branchiomma bairdi ( McIntosh, 1885 )

Capa, María & Murray, Anna, 2015, A taxonomic guide to the fanworms (Sabellidae, Annelida) of Lizard Island, Great Barrier Reef, Australia, including new species and new records, Zootaxa 4019 (1), pp. 98-167 : 107-109

Branchiomma bairdi ( McIntosh, 1885)

( Fig. 3A–B )

Dasychone bairdi McIntosh, 1885: 495 –497, pl. 30A, figs 13–15, pl. 39A, figs 2, 9; Monro, 1933: 267; Rioja 1951: 513 –516: pl. 1, figs 1–7; 1958: 286–287.

Branchiomma bairdi .— Tovar-Hernández & Knight-Jones 2006: 13 –17, figs 3A–D, H–K, 9C–D, 10C, 11B; Tovar-Hernández et al. 2009: 2–5, figs 2–4.

Material examined. Queensland, Lizard Island: AM W.197052, lagoon, 14°40'S, 145°27'E, 1977; AM W.35630, Mermaid Cove, 14°38′45′′S, 145°27′13′′E, coral rubble, 2 m, 8 Apr 2008; AM W.40925, south of Mermaid Cove, 14°38′53′′S, 145°27′E, coral rubble, 14.5 m, 1 Sep 2010; AM W.36486, Lagoon, 14°23′25′′S, 145°16′25′′E, sand, 1–10 m, 12 Feb 2009; AM W.40934, Lagoon between South Island and Palfrey Island, 14°41′50′′S, 145°27′1′′E, coral rubble, 2 m, 1 Sep 2010; AM W.40923 (2), MacGillivray Reef, 14°39′23′′S, 145°29′31′′E, coral rubble, 22 m, 29 Aug 2010; AM W.40895, AM W.40898, North Direction Island, south deep reef slope, 14°45′4′′S, 145°30′45′′E, 6–28 m, 4 Sep 2010; AM W.35629, Outer Barrier, Day Reef, 14°28′35′′S, 145°32′38′′E, Halimeda algae and coral rubble, 12 m, 16 Apr 2008.

Description of material examined. Specimens up to 25 mm long, 3 mm wide, with 4–8 thoracic and numerous abdominal chaetigers. Live specimens with radiolar crown with multiple thin green bands and orange spots between each pair of eyes, olive-green dorsal lips with an orange mid-rib ( Fig. 3A–B ). Body dark green with small brown spots. Interramal dark spots large on first thoracic segments ( Fig. 3A–B ), smaller on abdominal chaetigers. Preserved specimens with general dark brownish pigmentation, and darker spots. The orange spots on radioles remain for at least some time in most specimens ( Fig. 3B ). Radiolar crown with basal lobes semicircular or slightly involuted ventrally. Dorsal and ventral basal flanges absent. Basal membrane reduced. Radiolar flanges absent. Paired stylodes present, a generic feature in Branchiomma and unique among sabellids ( Fig. 3A–B ), digitiform, shorter than or similar to the width of rachis, except for macrostylodes mainly in distal half of radiole, strap-like, and up to four times as long as neighbouring pairs; unpaired basal stylodes present, also longer than width of rachis ( Fig. 3B ). Radioles with paired compound eyes, dark red or black, along lateral margins of radioles alternating with stylodes ( Fig. 3A–B ). Dorsal lips with long radiolar appendages; ventral lips and parallel lamellae present; ventral sacs outside or radiolar crown. Posterior peristomial ring collar with well separated dorsal margins; ventral lappets separated by a midventral incision ( Fig. 3A–B ). Glandular ridge on chaetigers anterior chaetigers absent. Interramal eyespots present in thorax and abdominal chaetigers. Ventral shields conspicuous, in contact with neuropodial tori ( Fig. 3A ); first one with M-shaped anterior margin. Collar chaetae with superior narrowlyhooded notochaetae, inferior spine-like notochaetae arranged in oblique rows. Following thoracic chaetigers with notopodia as conical lobes ( Fig. 3A–B ), with superior narrowly-hooded notochaetae, inferior spine-like notochaetae. Thoracic uncini avicular, with two rows of teeth over main fang, occupying about half of main fang, breast well developed, handle very short. Companion chaetae absent. Abdominal neuropodia as conical lobes with superior narrowly-hooded neurochaetae and inferior spine-like neurochaetae arranged in a C-shaped pattern. Uncini avicular, with three rows of teeth above main fang, breast well developed, handle very short. Pre-pygidial abdominal depression absent. Bilobed pygidium with eyespots on lateral margins. Pygidial cirrus absent. Leathery tubes covered with mud and sometimes, epifauna on anterior end.

Remarks. Branchiomma bairdi is distinguished from other congeners by the presence of strap-like and long macrostylodes (up to four times the length of the neighbouring digitiform stylodes, not so large in small specimens), and the colour pattern, with olive-green bodies and conspicuous bright orange spots alternating with radiolar eyes. This species was originally described from the Caribbean but has recently been reported is other biogeographical areas as an invasive species (Tovar-Hernández et al. 2009, 2012; Arias et al. 2013; Capa et al. 2013; Capa 2014). First record from Lizard Island.

Habitat. Associated with a variety of shallow water environments, ranging from fine sediments to hard substrates, including ship hulls, pylons, and other man-made surfaces.

Type locality. Bermuda.

Distribution. Caribbean, California, Eastern Mediterranean and Australia (Queensland).

Figures

FIGURE 3. A, B. Branchiomma bairdi, preserved specimens. A. Anterior end, ventral view, showing the radiolar crown, thorax and anterior abdominal chaetigers; B. Detail of base of radiolar crown, showing stylodes (black arrows) and paired compound eyes (white arrows) and anterior thoracic chaetigers, with collar dorsal margins widely separated; C – E. Branchiomma sp., live specimens; C. Whole specimen, ventral view, regenerating posterior end; D. Radiolar crown with paired radiolar eyes (white arrows) and stylodes (black arrows); E. Specimen with four thoracic chaetigers, anterior end, ventral view. Photographs: A – B by Eunice Wong.