Terebrasabella fitzhughi Murray & Rouse, 2007

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 : 155

Terebrasabella fitzhughi Murray & Rouse, 2007

( Fig. 23A–D )

Terebrasabella fitzhughi Murray & Rouse, 2007: 57 –61¸ figs 5–8.

Material examined. Queensland, Outer Yonge Reef, Great Barrier Reef: AM W.29465, 14°36′S, 145°38′E, rock and coral rubble with encrusting pink coralline algae, 9m, 21 Jan 1977; AM W.29466, 14°36′S, 145°28′E, coral rubble from bommie, covered in Lithothamnion and other algae, 30 m, 25 Jan 1977.

Other material examined. Tasmania: Holotype: AM W.29467, Eaglehawk Neck, 43°01′S, 147°55′E, inside spirorbid tubes attached to rock, intertidal, 3 Apr 1995. Paratypes: AM W.29468, AM W.29469 (2 on SEM), from same sample.

Description of material examined. Specimens up to 2.6 mm long and 0.5 mm wide, with eight thoracic and three abdominal chaetigers. Only preserved specimens studied, and all white. Anterior half of body slender, elongate and posterior abdomen slightly expanded, sac-like, external segmentation indistinct (generic features only shared with Caobangia Giard, 1893 , within Sabellidae ). Radiolar lobes semicircular, with two pairs of radioles with up to eight pinnules and filamentous distal ends. Ventral basal flanges present, dorsal basal flanges absent. Basal membrane, radiolar flanges and radiolar eyespots absent. Two rows of vacuolated cells support radioles basally. Dorsal lips with short radiolar appendages. Ventral lips, ventral sacs and parallel lamellae absent. Posterior peristomial ring collar indistinct dorsally, with elongate ventral lappets separated by a wide midventral incision ( Fig. 23A–B ). Glandular ridge on anterior chaetigers absent. Poorly developed ventral shields on chaetigers 1–5, 7–8 and 9–11. Collar chaetae broadly-hooded. Following thoracic notochaetae arranged in transverse rows on inconspicuous notopodia, broadlyhooded. Neuropodial uncini of chaetigers 2–6 acicular, with similar-sized teeth over the main fang, vestigial breast and long handle ( Fig. 23C ). Neuropodia of chaetigers 7–8 with numerous rasp-shaped avicular uncini with five or more rows of small teeth over the main fang, well developed breast and long handle ( Fig. 23D ). Companion chaetae present on chaetigers 2–6, with asymmetrical hood, with fibrous appearance for half hood length except marginally ( Fig. 23D ). Abdominal neurochaetae narrowly-hooded. Abdominal notopodial uncini acicular, similar to those in chaetigers 2–6. Pygidium inconspicuous, anus opening dorsally. Pygidial eyespots absent. Pygidial cirri absent. Tube a mucilaginous sheath, lining burrow inside dead coral.

Remarks. Of the three species of Terebrasabella described to date, T. fitzhughi is the only one with homodont teeth on uncini (i.e. similar-sized teeth on a crest above main fang). The other species described from Lizard Island, T. hutchingsae , is distinguished from T. fitzhughi by the presence of “palmate” uncini on chaetiger 2, while the type species, T. heterouncinata from South Africa, has crested uncini but with different-sized teeth above the main fang ( Murray & Rouse 2007).

Habitat. Rocks and coral rubble from intertidal to 30 m depth. Not abundant.

Type locality. Eaglehawk Neck, Tasmania.

Distribution. Australia (Tasmania: Eaglehawk Neck; Queensland: Great Barrier Reef).

Figures

FIGURE 23. A – D. Terebrasabella fitzhughi, scanning electron micrographs; A. Anterior end, ventral view, showing the ventral margins of collar separated by a narrow gap; B. Same, lateral view; C. Thoracic neuropodial uncini, chaetiger 3, with several rows of teeth above the main fang; D. Neuropodium chaetiger 3, showing the uncini and the companion chaetae with bent hoods, with proximal fibres; E – G. Terebrasabella hutchingsae; E. Anterior chaetigers, lateral view, showing “ palmate ” uncinus from chaetiger 2 (arrow); F. Detail of “ palmate ” uncinus; G. Uncini and companion chaetae, with bent hood and proximal fibers, chaetiger 2.