Sabellomma cupoculata

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 : 152-153

Sabellomma cupoculata Capa & Murray, 2015

( Fig. 22 E–F)

Sabellomma cupoculata Capa & Murray, 2015: 152 –155, fig. 22.

Material examined. Queensland, Lizard Island: Holotype: AM W.47193, High Rock, 14°49′34′′S, 145°33′08′′E, coral rubble, 20.1 m, 11 Sep 2010. Paratypes: AM W.47192, same as holotype; AM W.47191 (4), MacGillivray Reef, 14°39′23′′S, 145°29′31′′E, coral rubble, 22 m, 29 Aug 2010.

Other material examined. Queensland, Lizard Island: AM W.39545, off North Head, 14°38′44′′S, 145°27′12′′E, 12 m, 14 Apr 2008; AM W.37061, MacGillivray Reef, 14°39′23′′S, 145°29′31′′E, coral rubble, 22 m, 29 Aug 2010; AM W.37029 (2), AM W.37030, High Rock, 14°49′34′′S, 145°33′08′′E, coral rubble, 20.1 m, 11 Sep 2010; AM W.37057, MacGillivray Reef, deep reef slope, 14°39′25′′S, 145°28′22′′E, coral rubble, 30 m, 4 Sep 2010; AM W.43934, MI QLD 2351; AM W.44120, AM W.44121 (4), MI QLD 2359.

Description of material examined. Specimens up to 37mm long and 3.5 mm wide. Five to eight thoracic and numerous abdominal chaetigers. Live specimens with a colourful radiolar crown with a brownish base and brown, white and purple transverse bands arranged irregularly across radioles and pinnules. Pigment fades in preserved specimens and some only retain the brown pigment in crown and thorax, with or without white spots ( Fig. 22 E–F). Radiolar crown with semicircular basal lobes slightly involuted dorsally. Dorsal and ventral basal flanges absent. Six rows of vacuolated cells support the radioles basally. Radiolar flanges absent ( Fig. 22 F). Cup-shaped radiolar eyes irregularly arranged along side margins of all radioles, except distally ( Fig. 22 E–F). Dorsal lips with medium radiolar appendages; and one pinnular appendage fused to each dorsal lip, free for about 1/2 its length. Ventral lips and parallel lamellae present, ventral sacs absent. Posterior peristomial ring collar with dorsal margins separated by a wide gap, and low rounded ventral lappets separated by a midventral incision. Glandular ridge on anterior chaetigers absent. Thoracic ventral shields in contact with neuropodial tori; first ventral shield with indentation in anterior margin and m-shaped. Collar chaetae elongate, narrowly-hooded. Notopodia conical with chaetae arranged in longitudinal rows. Superior thoracic notochaetae elongate, broadly-hooded; inferior ones broadly-hooded chaetae with abruptly tapering distal tip (type A), with hoods 1.5 times the width of the shaft and as long as 4–5 times its maximum width. Thoracic uncini with 5–6 rows of teeth over main fang, covering just half its length, with well developed breast and short handle. Companion chaetae subdistally enlarged, hood with fibrous appearance, and with thin distal mucro flattened transversely and narrowing abruptly, tapering to a long fine point. Abdominal neurochaetae narrowly-hooded. Abdominal uncini with 5–6 rows of teeth large teeth over main fang covering half its length, with breast less defined and handle shorter than thoracic uncini. Pygidium as a rim around a ventral anus, with eyespots on both sides. Pygidial cirrus absent. Tube thin, flexible, and semitranslucent with some fine sediment particles attached.

Remarks. Sabellomma cupoculata resembles the other three congeners, all described from the Western Atlantic, in the presence of irregularly distributed lensed eyes on outer margins of radioles, and the presence of companion chaetae with flattened transversely distal mucro. Sabellomma cupoculata is distinguished, however, by the form of the companion chaetae with very thin mucros, radioles that are supported by six vacuolated cells in S. cupoculata but four in the other three species, the absence of ventral sacs and the pigmentation pattern (none of the previously described species have bright purple bands in the crown when alive).

Habitat. Coral rubble, coarse sand, under boulders and live corals, between 3–30 m depth.

Type locality. Lizard Island.

Distribution. Tropical Australia, from northern Western Australia to southern Queensland.

Figures

FIGURE 22. A – D. Sabellastarte sp. A. Live specimens with radiolar crown exposed outside the tube; B. Dorsal view, showing collar dorsal margins fused to faecal groove forming pockets at either side (white arrow); radiolar lobes with dorsal basal flanges (black arrow); C. Same, lateral view, showing the pigmentation pattern, including the interramal eyespots (white arrow) and the arrangement in a C shape row of inferior abdominal chaetae (black arrows); D. Juvenile showing a different pigmentation pattern to adults; E – F. Sabellomma cupoculata. A. Incomplete specimen, showing pigmentation pattern and rows of ocelli along radiolar margins (arrows); F. Detail of radioles and ocelli (arrows); G – J. Stylomma palmatum, live specimen; G. Anterior end showing the rigid radiolar crown with elongated basal lobes; H. Detail of radiolar tip with unpaired subdistal stalked compound eyes (arrow); I. Anterior abdominal chaetigers, with anterior collar margin incised midventrally and thoracic tori almost in contact with ventral shields; J. Detail of basal lobes, dorsally, showing the flanges joined dorsally with a press stud structure (arrow).