Streptosyllis aequiseta Hartmann-Schröder, 1981

San Martin, G & Hutchings, PA, 2006, Eusyllinae (Polychaeta: Syllidae) from Australia with the Description of a New Genus and Fifteen New Species, Records of the Australian Museum 58, pp. 257-370 : 355

Streptosyllis aequiseta Hartmann-Schröder, 1981

Figs 82A–I, 83A–F

Streptosyllis aequiseta Hartmann-Schröder, 1981: 32 , figs 53– 58; 1983: 131, fig. 15; 1984: 21; 1985: 70; 1989: 26.— Böggemann et al., 2003: 21, figs 3, 4.

Material examined. AUSTRALIA: NEW SOUTH WALES: Weeney Bay, Botany Bay , 34°01.3'S 151°09.7'E, mud, 1 m, coll. A. Roach & A. Jones, 30 Mar 1995, 1 ( AM W23562) ; Weeney Bay, Botany Bay , 34°01.3'S 151°09.7'E, mud, 1 m, coll. A. Roach & A. Jones, 30 Mar 1995, 1 ( AM W23567) . WESTERN AUSTRALIA: Bush Bay , 30 km S of Carnarvon, 25°10'S 113°39'E, lumps of algae on shallow sandflats, intertidal, coll. H.E. Stoddart, 6 Jan 1984, 2 ( AM W27654) ; inshore limestone reef, Ned’s Camp, Cape Range National Park , 21°59'S 113°55'E, fine sediment & sand from patches in reef, 1 m, coll. H.E. Stoddart, 2 Jan 1984, 2 ( AM W26782) ; N end of beach, Bundegi Reef, Exmouth Gulf , 21°49'S 114°11'E, rocky rubble, coralline algae with green epiphyte, 1.5 m, coll. H.E. Stoddart, 4 Jan 1984, 1 on SEM stub ( AM W28370) .

Description. Up to 4.9 mm long for 36 chaetigers (mature specimen), but usually smaller; examined specimens up to 1.4 mm long, 0.2 mm wide, with 23 chaetigers; fragile, often broken and damaged. Prostomium oval, with 4 eyes arranged in an open trapezoidal pattern and 2 anterior eyespots ( Fig. 82A). Antennae smooth, club-shaped, similar in length to prostomium or longer, median antenna inserted between anterior eyes, lateral antennae inserted near eyespots. Palps reduced to 2 small, sometimes indistinct papillae ( Figs 82A, 83B). Peristomium shorter than subsequent segments; tentacular cirri similar to antennae, dorsal ones slightly longer than ventral tentacular cirri. Dorsal cirri similar in shape and size to antennae ( Fig. 82A) with distinct cirrophores. Parapodial lobes elongated, subrectangular, ending as rounded lobe ( Fig. 82B), those of chaetigers 2–6 enlarged and truncated distally. Ventral cirri digitiform, elongated, longer than parapodial lobes, arising from about middle of ventral side of parapodial lobes ( Figs 82B, 83A). Compound chaetae with homogomph articulations on anterior parapodia ( Figs 82C,D, 83D), and hemigomph on mid to posterior parapodia ( Figs 82F, 83C), provided with distinct subdistal spine on shafts, and bidentate blades, with short spines on margin. Anterior parapodia with 2 compound chaetae with elongate blades, about 21 µm long, distinctly bidentate, both teeth well separated ( Figs 82C, 83D), and 6 compound chaetae with shorter blades ( Fig. 82D), within fascicle blades 10 µm in length dorsally, 6 µm in length ventrally; difference between 2 types of chaetae becoming progressively less marked along body; posterior parapodia with 6 compound chaetae ( Fig. 82F), bidentate with short spines on margin, dorsoventral gradation in length of blades within fascicle, 25 µm long dorsally, 9 µm long ventrally. Dorsal simple chaetae from chaetiger 1, unidentate, with minute serration on margin and distinct concave, translucent hood, covering tip of chaetae, small on simple chaetae of anterior parapodia ( Figs 82E, 83E) but becoming more developed posteriorly ( Figs 82G,H, 83F). Aciculae knobbed at tips, enlarged on chaetigers 2–6 ( Fig. 82I). Pharynx extending through 3–4 segments, with crown of 10 soft papillae on margin ( Fig. 83A). Proventricle large, pyriform, extending through about 6 segments and 40–48 indistinct muscle cell rows. Pygidium small, with 2 anal cirri and median papilla.

Remarks. All Australian specimens have all dorsal cirri smooth; those from the Seychelles ( Böggemann et al., 2003) have longer dorsal cirri, articulated, with two glands on each article, except anteriormost, which are smooth. Until more material is available, it is unknown as to the levels of variation of articulation of dorsal cirri that may occur within a species. So at this stage we are tentatively accepting the records of this species from the Seychelles.

Habitat. Occurring interstitially in coralline sand, fine sand, mud, on algae, from intertidal to shallow depths.

Distribution. Australia (Western Australia, South Australia, Tasmania, New South Wales), possibly Seychelles Islands.