Syllis

Aguado, Teresa, Martín, Guillermo San & Ten, Harry A., 2008, Syllidae (Annelida: Polychaeta) from Indonesia collected by the Siboga (1899 – 1900) and Snellius II (1984) expeditions, Zootaxa 1673, pp. 1-48 : 39-41

Syllis sp. 1

Fig. 19

Material examined. 1 spec. ZMA V.Pol. 1993 (as Syllis zonata ), Indonesia, Maluku, Kur Isl., anchorage off Kilsuin, coral, dredge, 20–45m, Siboga Expedition, Sta. 250, 6/ 7 Dec. 1899.

Description. Specimen incomplete, 12.5 mm long, 0.4 mm wide, with 91 segments. Body circular in cross-section, ventrally flattened. Strongly pigmented dark red. Prostomium wider than long, no visible eyes.

Median antenna inserted on middle of prostomium, longer than combined length of prostomium and palps, with 26 articles. Lateral antennae inserted anteriorly, longer than median antenna, with 32 articles. Palps broad, fused at base with distinct median groove, slightly longer than prostomium. Peristomium partially covering prostomium ( Fig. 19 A). Dorsal tentacular cirri slightly longer than lateral antennae, with 32–45 articles, ventral ones shorter, with 28 articles. Dorsal cirri alternating in length, longer ones with about 45 articles and shorter ones with 22. Articles of anterior dorsal cirri shorter than those of posterior-most dorsal cirri. Cirrophores present on all parapodia. Ventral cirri inserted proximally, conical, not extending beyond parapodia. Parapodia triangular, with pre- and postchaetal lobes similar in length ( Fig. 19 F). Anterior chaetigers with five to eight compound heterogomph chaetae. Blades bidentate (ca. 25–30 µm) with spines on margin ( Fig. 19 B). Midbody parapodia with five to six compound chaetae. Blades shorter than those of anterior chaetigers (ca. 20–25 µm), bidentate, both teeth similar in size and length, spines on margin. Shafts with distal spines ( Fig. 19 C). Posterior parapodia with six compound chaetae, equal in length to blades from midbody chaetigers. Blades bidentate with both teeth similar in size and length, with long marginal spines. Shafts with distal spines ( Fig. 19 E). One simple dorsal chaeta in posterior chaetigers, straight, with subdistal, short projection ( Fig. 19 D). Ventral simple chaetae not seen. Four aciculae in anterior parapodia, three straight and blunt and one curved ( Fig. 19 G). Posterior parapodia with two pointed aciculae ( Fig. 19 H), one of them protruding beyond parapodia. Pygidium missing. Pharynx long, similar in length to proventricle, extending through 12 segments, with anterior conical tooth. Proventricle long, extending through 11 segments, with about 39 cell-rows ( Fig. 19 A).

Remarks. There are other taxa with long cirri alternating in length and similar chaetae. This specimen is most similar to Syllis lutea , but the blades of its midbody and posterior compound chaetae show a proximal tooth considerably wider than the distal one, the spines of the blades are longer and curved, and as long as the proximal tooth ( Hartmann-Schröder, 1960, Licher, 1999). In Syllis sp. 1, blades of compound chaetae do not have a proximal tooth wider than the distal one and the distal spines, although long, are never as long as the secondary tooth. Similar differences exist between Syllis sp. 1 and S. glarearia . Blades of compound chaetae in S. glarearia also have a wide and long proximal tooth and long spines, of which at least one or two are as long as the proximal tooth. Moreover, S. glarearia has bidentate simple dorsal chaetae, unidentate as present in S. sp. 1 ( Westheide, 1974, Licher, 1999). In Syllis jorgei San Martín & López, 2000 (Mediterranean Sea) the long spines of the blades are longer than the distal teeth ( San Martín & López, 2000; San Martín, 2003). The absence of eyes in this species may be a result of the time spent in alcohol. Identification to species is not possible given its condition.

Distribution. Indonesia.

Figures

FIGURE 19. Syllis sp. 1. ZMA V. Pol. 1993. A: Anterior part, dorsal view; B: Anterior chaetae; C: Midbody chaetae; D: Dorsal simple chaeta; E: Posterior chaetae; F: Midbody parapodium, anterior view; G: Anterior aciculae; H: Posterior aciculae. Scale A: 0.2 mm; B-E, G-H: 20 µm; F: 1 mm.