Semivermilia lylevaili n. sp.

(Figs 20, 21)

Material examined. Holotype: specimen in tube fragment (Fig. 20 A) AM W.47579, stn.G237, Patch Reef near Palfrey Island, coll. G. Rouse & E. Kupriyanova, 30 Oct 2005. Paratypes: AM W.47458 (2 without tubes), stn.G241, off Osprey Island, coll. G. Rouse & E. Kupriyanova, 31 Oct 2005; AM W.47582 (1 used for SEM), stn.G244, off South Island, coll. G. Rouse & E. Kupriyanova, 2 Nov 2005; SAM E3629, stn.G237, Ser59, Patch Reef near Palfrey Island, coll. G. Rouse & E. Kupriyanova, 30 Oct 2005.

Additional material: AM W.45076, MI QLD 2417 (5); AM W.45077, MI QLD 2417 (2); AM 47631, MI QLD 2386; AM W.47632, MI QLD 2352; AM W.47633, MI QLD 2406.

Description. TUBE: white, about 0.4 mm wide, with lumen of 0.3 mm. Circular in cross section, with two not very distinct longitudinal ridges (Fig. 20 A), without flaring peristomes; granular overlay absent.

BRANCHIAE: with 5–6 pairs of radioles, arranged short pectinately, not connected by inter-radiolar membrane. Branchial eyes absent (Fig. 20 B, C).

PEDUNCLE: smooth, circular in cross section, inserted just below first and second normal radiole; without wings, clearly separated from opercular ampulla by a constriction (Fig. 20 B, C).

OPERCULUM: slightly asymmetrical, with simple convex thin brownish endplate, terminal spine absent (Figs 20 A–C, 21A). Pseudoperculum absent.

COLLAR AND THORACIC MEMBRANES: collar relatively high, trilobed, continuous with thoracic membranes ending at 2nd thoracic chaetiger (Fig. 21 A).

THORAX: with collar chaetiger and 6 uncinigerous chaetigers. Tori positioned along mid-line, triangular depression absent. Collar chaetae limbate of two sizes (Fig. 21 B). Subsequent chaetae limbate, of two sizes, with Apomatus chaetae starting at chaetiger 3 (Fig. 21 C). Uncini saw-to-rasp shaped, with up to 15 teeth in profile view and up to 4 teeth in the row above the wide gouged peg (dental formula depending place in row from P:4:4:2:1:2:2:1:1: 1, 9 in profile view, to P:4:3:2:2:2:1:1:1:1:1:1:1:1: 1, 14 in side view) (Fig. 21 D).

ABDOMEN: abdominal chaetigers up to 30. Uncini rasp-shaped, with 8–10 rows of 7–3 teeth each above wide, slightly crenulated peg (Fig. 21 F). Chaetae narrow flat geniculate with rounded teeth (Fig. 21 E). Achaetous anterior abdominal zone short. Posterior glandular pad absent. Long posterior capillary chaetae absent (Fig. 21 A).

SIZE: length up to 1.6 mm, width of thorax 0.2 mm. Branchiae and operculum accounting for 1/3 of entire length.

COLOUR: orange to yellow (Fig. 20).

Etymology. The species is named after Dr Lyle Vail, director of LIRS .

Remarks. By its simple operculum, this new species resembles S. annehoggettae n. sp., but lacks distinct elongated ovicells typical for the latter species.

Reproduction. Lecithotrophic larvae brooded inside the tube.

Type locality. Lizard Island, Qld, Australia.

Distribution. Qld, Australia.