Syllis patersoni Soto, San Martín & Lucas, 2020: 153 The genus Syllis Savigny in Lamarck, 1818 (Annelida: Syllidae: Syllinae) from Australia (Fourth part) Martín, Guillermo San Lucas, Yolanda Hutchings, Pat Zootaxa 2024 2024-05-17 5453 1 1 32   Syllis patersoni  Soto, San Martín & Lucas, 2020: 153   85S3W Soto, San Martin & Lucas, 2020 Soto, San Martin & Lucas 2020 [151,746,150,178] Polychaeta Syllidae Syllis Animalia Phyllodocida 10 11 Annelida species patersoni   Figure 6      Syllis patersoni Soto, San Martín & Lucas, 2020: 153, fig. 7   Material examined.  AUSTRALIA, WESTERN AUSTRALIA: Kimberley region, East Montalivet Island, 15° 06’ S, 125° 18’ E,  0–6 m,  15–16 July 1988, intertidal, AMW.54232, 1 specimen.  NORTH TERRITORY: Darwin Harbour, NT349, East Point, 12° 24’ 36” S, 130° 39’ 57” E, coll. by hand on SCUBA,  7–10 m,  17 July 1993, coral rubble and algae, AMW.54231, 1 specimen;  Dudley Point, NT319, 12° 24’ 54” S, 130° 49’ E, coll. by SCUBA,  7–8 m  18 July 1993, coral rubble and algae, AMW.54230, 1 specimen.   Description. Body elongated, slender, without colour markings; complete, twisted specimen, 8 mmlong, 0.35 mm wide, 88 chaetigers. Prostomium almost circular; palps elongated. Dorsal cirri similar in length to body width, longer on anterior segments, slender, elongated, somewhat fusiform, with numerous spiralized glands inside articles ( Fig. 6, A, B), giving a dark appearance; dorsal cirri from proventricular segments alternating long cirri, with 23 articles, and short ones, with 17 articles ( Fig. 6B). Parapodia conical; ventral cirri digitiform. Compound chaetae with few short, slender, spiniger-like chaetae ( Fig. 6D, F, H) and several heterogomph falcigers with bidentate blades, proximal teeth slightly smaller than distal ones, and short spines on margin, with dorso-ventral gradation in length ( Fig. 6C, E, G), similar throughout. Anterior parapodia each with 2₋₋3 short spiniger-like chaetae, blades 60 µm ( Fig. 6C) and 11₋₋12 falcigers with dorso-ventral gradation, blades 36 µm above, 23 µm below ( Fig. 6D); midbody parapodia each with 1₋₋2 spiniger-like chaetae, blades 55 µm long ( Fig. 6E) and 6₋₋7 falcigers, blades 25 µm above, 16 µm below ( Fig. 6F); posterior parapodia each with one (sometimes two) spiniger-like chaetae, shorter than those of midbody and anterior segments, blades 52 µm long ( Fig. 6G), and 5₋₋6 falcigers, blades 20 µm above, 16 µm below ( Fig. 6H). Dorsal and ventral simple chaetae not seen. Anterior parapodia with four slender, pointed aciculae ( Fig. 6I), two in midbody parapodia, distinctly thicker ( Fig. 6J), and one single in posterior parapodia, acuminate ( Fig. 6K). Pharynx long and slender, through 10 segments. Proventricle slender and long, shorter than pharynx, through seven or eight segments, with 35₋₋47 muscle cell rows. Pygidium small, with two long anal cirri, with 12 articles.   Remarks. The presence of this species in Australiais surprising, since it was described from very cold waters in Chile. However, this specimen agrees quite well with the original description, although the specimen is smaller than the typematerial. It is very similar to  Syllis beneliahuae Campoy & Alquézar, 1982) (see Soto et al., 2020), but the dorsal cirri are longer, distally pointed, with more articles, and the spiniger-like chaetae are shorter relative to the falcigers (about twice as long in  S. patersoniand three times longer in  S. beneliahuae). However, this distribution should be confirmed by molecular studies.   Distribution. Chilean Patagonia. Australia(WA, NT).  Habitat. From boulders, sediment bottoms and associated with  Macrocystis pyriferaholdfasts in fjords, islands and channels from Chilean Patagonia. Shallow subtidal to about  30 m. 4866331310 1988-07-15 1988-07-16 1988-07-15 AM Australia 3 -15.1 East Montalivet Island 1286 125.3 Kimberley region 10 11 1 Western Australia 4866331303 1993-07-17 SCUBA, AM Darwin Harbour, NT Australia 9 -12.41 East Point 21 130.66583 10 11 1 NORTH TERRITORY 4866331315 1993-07-18 SCUBA, AM Dudley Point, NT Australia 8 -12.415 903 130.81667 10 11 1 NORTH TERRITORY