Notaulax

Notaulax sp. 2

(Fig. 16 H–J)

Material examined. Queensland, Great Barrier Reef: AM W.41399 (crown), North Direction Island, 14°44′43′′S, 145°30′18′′E, 8 m, 26 Aug 2010; AM W.41402, Day Reef, 14°28′30′′S, 145°32′12′′E, 17 m, 5 Sep 2010. Lizard Island: AM W.22570 (15), between Bird and South Islands, 14°40′S, 145°28′E, 12 m, dead Porites coral blocks, Jan 1987; AM W.41375, AM W.41400 (crown), MacGillivray Reef, 14°38′53′′S, 145°29′12′′E, coral rubble, 14 m, 31 Aug 2010; AM W.41397 (2), MacGillivray Reef, 14°39′23′′S, 145°29′31′′E, 22 m, 29 Aug 2010; AM W.41398, Turtle Beach, 14°39′08′′S, 145°27′04′′E, 1 m, 30 Aug 2010; AM W.47233 (crown), MacGillivray Reef, 14°39′23′′S, 145°29′31′′E, coral rubble, 22 m, 29 Aug 2010; AM W.41376, AM W.47394 (2), Watsons Bay, 14°39′26′′S, 145°27′03′′E, coral rubble, 4.5 m, 28 Aug 2010; AM W.197050 (2), lagoon, drop off between Bird Islet and South Island, 14°42′S, 145°28′E, dead coral rock, 9 m, Apr 1978; AM W.43874, MI QLD 2331; AM W.43943, MI QLD 2356 (crown); AM W.44216, MI QLD 2381 (1 + 2 crowns).

Description of material examined. Longest specimen over 35 mm long, 1.5 mm wide, with 7–8 thoracic and numerous abdominal chaetigers. Radiolar crown with dark and white transverse bands, especially conspicuous on pinnules and lateral margins of radioles (Fig. 16 H–I). Radiolar ocelli dark brown (Fig. 16 H). Thoracic chaetigers light orange, with pigmentation fading towards abdominal segments (Fig. 16 J). Some specimens maintain the colour of the radiolar crown but pigmentation fades after fixation and preservation. Radiolar crown with semicircular, thick, stout elongate branchial lobes (Fig. 16 H), fused dorsally near the base of radioles. Dorsal and ventral basal flanges along the branchial lobes. Basal membrane between radioles, along 1/3 of their length; radioles with narrow distal radiolar flanges, bare tips of medium length (as long as the length on one pinnule) (Fig. 16 H). Four rows of vacuolated cells supporting radioles basally. Up to 30 ocelli arranged in a single row along radiole from the margin of basal membrane to distal pinnules. Dorsal lips long, without radiolar appendages. Ventral lips and parallel lamellae present; ventral sacs absent. Posterior peristomial collar complete, higher ventrally, entire or with a small midventral incision, and may be notched middorsally. Glandular ridge absent on anterior chaetigers.

Thoracic ventral shields in contact with adjacent neuropodial tori, first ventral shield with straight anterior margin (Fig. 16 J). Interramal eyespots absent. Collar chaetae arranged in long J- or C-shaped curved rows, spine-like. Following thoracic chaetigers with conical notopodia; superior thoracic chaetae broadly-hooded, inferior paleate, without mucro. Thoracic neuropodia with avicular uncini with tiny teeth above the main fang, covering more than half its length, well developed breast and medium-sized handle. Companion chaetae with asymmetrical hood, and loose fibres on most of hood surface. Abdominal neurochaetae on short, slightly elevated neuropodia, with superior paleate chaetae with long mucro and inferior elongate narrowly-hooded chaetae. Neuropodial uncini similar to thoracic but with teeth covering more than three quarters of main fang. Pygidium a rounded lobe, few red spots may be present ventrolaterally. Tube thick, orange, transparent and chitinous, without attached sediment.

Remarks. The material examined shows broad variation in the morphology of the anterior margin of the collar, and some specimens possess an entire collar margin, while others have a small midventral incision and/or a dorsal notch, neither of which extend down to chaetiger 2. Intraspecific variability in collar morphology has been reported for some species, typically with the presence of a midventral incision in juveniles (e.g., Perkins 1984). Notaulax fuscotaeniata (Grube, 1874), was originally described from Sri Lanka as having a collar incised ventrally, and radiolar ocelli in a series of about 30 on each side extending from just above palmate membrane to near tips (Perkins 1984), features that are similar to those observed in the specimens described herein. Nevertheless, other details would need to be checked with type material as Grube ′s original description is brief, before assigning these specimens to this species or describing it as new.

Habitat. Dead coral and coral rubble, 6–15 m depth.

Type locality. Lizard Island.

Distribution. Australia (Queensland: Lizard Island).