Astreptosyllis acrassiseta Kudenov & Dorsey, 1982

Astreptosyllis acrassiseta Kudenov & Dorsey, 1982 View in CoL

Figs 7A–I, 8A–F

Astreptosyllis acrassiseta Kudenov & Dorsey, 1982: 576 View in CoL , fig. 1.

Material examined. AUSTRALIA: NEW SOUTH WALES: Off Bass Point , 34°36'S 150°54'E, 50 m, 1 Feb 1990, 1 ( AM W22995) GoogleMaps . VICTORIA: Port Phillip Bay , 38°16.3'S 144°41.5'E, medium sand, 13 m, Feb 1971, 1 paratype, ( AM W18587) GoogleMaps . WESTERN AUSTRALIA: Ned’s Camp, Cape Range National Park , 21°59'S 113°55'E, limestone reef near shore, fine sediment & sand from patches in reef, 1 m, coll. H.E. Stoddart, 2 Jan 1984, 1 ( AM W26780) GoogleMaps .

Description. Body up to 3.1 mm long, 0.3 mm wide, with 42 chaetigers. Prostomium rectangular, 2 pairs of eyes in trapezoidal arrangement; antennae slightly club-shaped, unarticulated, usually missing; median antenna arising from posterior margin of prostomium, between posterior eyes, lateral antennae originating between anterior eyes. Palps large, similar in length to prostomium, basally totally fused ( Figs 7A, 8A), directed anteriorly, provided with distal constriction. Tufts of cilia on lateral areas of prostomium and peristomium ( Fig. 7A). Tentacular cirri and dorsal cirri of subsequent 2 segments similar to antennae; dorsal cirri from chaetiger 3 articulated ( Figs 7A, 8A), slender, slightly longer than body width, with about 6–10 elongated articles, some with 1–2 granular, dark inclusions ( Fig. 7A,C). Parapodia of anterior segments relatively broad in contrast, to posterior ones, distally truncated, with some distal incisions ( Fig. 7B); becoming elongated and conical from proventricular segments onwards, with dorsal band of long cilia ( Fig. 7C). Ventral cirri of anterior parapodia broad, shorter than parapodial length, becoming greatly elongated posteriorly, longer than parapodial length, arising from about middle of ventral side of parapodial lobes ( Fig. 7C). Anterior 1–6 chaetigers each with 8–10, sometimes 12, compound chaetae with enlarged shafts, hemigomph articulation, with short, stout, broad blades, apparently unidentate or bifid, with distal incision ( Figs 7E, 8B), about 8–15 µm long. From chaetiger 7 onwards, parapodia with 5–8 compound chaetae with shafts much slender than those of anterior chaetae, heterogomph, with fine spines on margin ( Figs 7G, 8C,D), and blades slender, unidentate, some with distal hood, with minute spines on margin, and dorsoventral gradation in length of blades within fascicle ( Fig. 8C), 27 µm in length dorsally and 15 µm in length ventrally; under SEM, margin with several rows of spines ( Fig. 8E) and distal hood composed of minute spines ( Fig. 8E). Acicula solitary, distally knobbed ( Fig. 7B,H). Dorsal simple chaetae from chaetiger 1, thick, tip tapered, blunt, covered with longitudinally striated, rounded hood ( Fig. 7D,F); under SEM, dorsal simple chaetae with “ Banksia -like” or “artichoke-like” appearance. Ventral simple chaetae usually absent, but one specimen with single thin, smooth, filiform, ventral simple chaeta ( Fig. 7 I) on each fascicle of last parapodium. Pharynx through about 7–8 segments, with crown of 10 soft papillae ( Fig. 7A). Proventricle through about 7–8 segments, with 30–32 muscle cell rows. No specimens with anal cirri present, probably present on undamaged specimens.

Habitat. Occurring in median to coarse sand; from intertidal to 50 m.

Distribution. Australia ( Victoria, New South Wales, Western Australia).