Pionosyllis sp.

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 : 351-353

Pionosyllis sp.

Fig. 79A–G

? Pionosyllis divaricata Haswell, 1920: 104 , pl. 13, figs 2, 3. Not Keferstein, 1862: 11.

? Eusyllis sp. Hartmann-Schröder, 1984: 19, fig. 27.

Material examined. AUSTRALIA: NEW SOUTH WALES: NE corner of Clark Is., Port Jackson , 33°51.85'S 151°14.7'E, within encrustation on outside of bottle, 4.5 m, coll. P.A. Hutchings, 17 Apr 1996, 1 anterior & 1 posterior fragment ( AM W28410) .

Description. Both fragments in poor condition; anterior fragment of 19 segments and mid-posterior fragment of 8 segments. Similar to Pionosyllis rousei , but compound chaetae more elongate, with longer spiniger-like chaetae and elongated falcigers; anterior parapodia with numerous compound chaetae, blades of spiniger-like chaetae about 69 µm long, bidentate, both teeth small and equal in size ( Fig. 79A); falcigers with blades 45–49 µm in length, proximal tooth distinctly curved but lacking tendon ( Fig. 79B). Midbody parapodia with some spiniger-like chaetae, blades about 89 µm in length, teeth distinctly hooked, but lacking tendon ( Fig. 79C); falcigers with blades 40–51 µm in length, most provided with tendon ( Fig. 79D). Posterior parapodia with single spiniger-like chaetae, long and slender, blades 90 µm in length, with proximal tooth distinctly curved, indistinct tendon ( Fig. 79E); falcigers with both teeth marked, curved, proximal tooth longer than distal tooth, with distinct tendon between proximal tooth and blade edge ( Fig. 79F) 42–58 µm in length. Dorsal and ventral simple chaetae not seen. Aciculae distally blunt, with short pointed tip; 2 acicula on anterior parapodia ( Fig. 79G), and 1 on posterior parapodia ( Fig. 79H). Pharynx everted, with crown of 10 long, slender soft papillae, pharyngeal tooth located near anterior margin of pharynx. Proventricle short and wide, through 10 segments, with about 27 muscle cell rows.

Remarks. This species does not agree with any other described species within the genus Pionosyllis . Additional complete material, however, is necessary before it can be described as new species.

sediments, 12 m, coll. P.A. Hutchings & party, 18 Aug 1989, 1 ( AM W24706). Paratype WESTERN AUSTRALIA: Dunsborough , 33°36'S 115°06'E, fine sand, intertidal, coll. G. Hartmann-Schröder, 9 Nov 1975, ( AM W196215 ) .

Description. Body proportionally broad in relation to other species of genus, 3.1 mm long, 0.4 mm wide, with 29 segments. Prostomium oval, width more than twice length; 2 pairs of eyes in open trapezoidal pattern, close to each other, laterally inserted; antennae shorter than combined length of prostomium and palps ( Fig. 80A), slightly rugose, median antenna originating between anterior eyes, slightly longer than lateral antennae; lateral antennae shorter than prostomium, inserted near anterior margin of prostomium. Palps broad, fused for almost entire length, except for distinct terminal notch, ventrally folded on one specimen ( Fig. 80B). Peristomium shorter than following segments; dorsal tentacular cirri longer than median antenna, similar in shape, ventral tentacular cirri shorter than dorsal ones. Dorsal cirri smooth, similar to antennae and tentacular cirri, rough, slightly enlarged on middle, tapered basally and distally, longer than parapodial lobes ( Fig. 80A), shorter than half of body width. Parapodial lobes broad, bilobed dorsally ( Fig. 80A). Ventral cirri short, oblong, shorter than parapodial lobes. Compound chaetae similar throughout, heterogomph falcigers, blades short, about 12–14 µm in length, short spines on margin, some apparently unidentate, others with prominent proximal tooth located on different plane ( Fig. 80C), about 20–25 per parapodium. Dorsal simple chaetae from anterior segments, unidentate, distally knobbed and provided with small transparent hood and short spines on margin ( Fig. 80D). Ventral simple chaetae on posterior chaetigers, smooth, bidentate, both teeth similar ( Fig. 80E). Aciculae distally knobbed ( Fig. 80F), 3 present anteriorly, decreasing to 1 on most posterior chaetigers. Pharynx wide, through 5–6 segments, pharyngeal tooth located laterally, near proventricle ( Fig. 80A). Proventricle barrel-shaped, massive, through 4–5 segments, with about 50 muscle cell rows.

Remarks. This species differs in several characters from the recently emended description of Opisthodonta , in having fused palps, short cirri, a massive proventricle and large pharynx without soft papillae as well as a pharyngeal tooth located laterally, not mid-dorsally; furthermore, Opisthodonta as redefined above is characterized by having ventral cirri of anteriormost segments expanded leaf-like, partially fused with parapodial lobes, whereas in this species the ventral cirri are short and ovoid. We are therefore transferring Opisthodonta curticirris Hartmann-Schröder to the genus Psammosyllis as the above characters clearly place it in this genus rather than the emended genus Opisthodonta . The genus Psammosyllis contains only two other previously described species P. aliceae Westheide, 1990 , described from India, and P. wui Ding & Westheide, 1997 , described from China. Psammosyllis curticirris differs from these two species by having a broader body, dorsal simple chaetae with a distal hood, and compound chaetae with blades unidentate or bidentate with both teeth on different planes (see Westheide, 1990; Ding & Westheide, 1997). This represents the first record of the genus in Australia.

Habitat. Occurring in sandy substrates, from intertidal to shallow depths.

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