Syllis cf. cruzi Núñez & San Martín, 1991

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 : 25-27

Syllis cf. cruzi Núñez & San Martín, 1991

Fig. 10

Material examined. 1 spec. ZMA V.Pol. 5262, Indonesia, Komodo, NE cape, 08°29'S 119°34.1'E, sandy bottom, algae, occasional sponges and tunicates, 30–34 m, Snellius II, Sta. 4.096d, 19/ 20 Sept. 1984.

Comparative material examined. Syllis cruzi Núñez & San Martín, 1991 . Several spec. MNCN 16.01/ 6744, Spain, Castellón, Is. Columbretes, N de Columbreta Grande, 39°54' 02"N 00°41'15"E, 47 m, 12 July 1994; several spec. MNCN 16.01/6745, Spain, Is. Baleares, Mallorca, Punta de la Foradada, 39º44'33"/ 39º45' 80"N 02º31' 86"/ 02º33' 51"E, 72–74 m, 25 Jun. 1994 (all identified by San Martín, 2003).

Syllis curticirris ( Hartmann-Schröder, 1981) . Holotype ZMH P16462 and paratype ZMH P16463, Central Atlantic Ocean, Meteor Bank, 29º58.6’N 28º25.1’W, 300– 330 m.

Description. Specimen 15 mm long, 0.5 mm wide, with 117 segments. Distinct glandular bands in lateral and posterior margins of each segment ( Fig. 10 A). Prostomium wider than long, with two pairs of eyes in trapezoidal arrangement, anterior ones larger than posterior pair, eyespots absent. Median antenna inserted on middle of prostomium, between anterior pair of eyes, slightly longer than combined length of prostomium and palps, with 18 articles. Shorter lateral antennae inserted on anterior margin of prostomium, with 13 articles. Palps broad, triangular, longer than prostomium, fused at base, with median groove. Peristomium shorter than subsequent segments ( Fig. 10 A). Dorsal tentacular cirri equal in length to median antenna, with 18 articles, ventral ones shorter, with 11 articles. Anterior-most dorsal cirri longer than subsequent ones, with 16–19 articles; from chaetiger 4 backwards, dorsal cirri shorter, with 12–13 articles. Posterior dorsal cirri short, with 7– 10 articles. Ventral cirri digitiform, proximally inserted, shorter than parapodia. Anterior parapodia each with 13–14 compound, heterogomph chaetae. Bidentate blades (ca. 23–26 µm) with two to three distal spines on blade edge longer than basal ones ( Fig. 10 B). Posterior chaetigers with 12 bidentate compound chaetae, shorter and thicker than those of anterior chaetigers (most dorsal ca. 23 µm, most ventral ca. 16 µm), with spines on blade edge; two to three most distal spines much longer than others, reaching to level of proximal tooth ( Fig. 10 F). One unidentate, dorsal simple chaeta with short distal spines ( Fig. 10 D). One bidentate ventral simple chaeta in posterior parapodia, with three long spines on tip ( Fig. 10 E). Anterior parapodia with three aciculae, two pointed and other distally curving ( Fig. 10 C); posterior parapodia with one acicula distally curving ( Fig. 10 G). Pygidium regenerating, two anal cirri with 10–11 articles. Pharynx equal in length to proventricle, through eight segments; conical tooth on anterior margin. Proventricle with about 31 cell-rows with distinct longitudinal midline ( Fig. 10 A).

Remarks. Syllis cruzi has been reported from the Atlantic Ocean (Canary Islands) ( Núñez & San Martín, 1991) and Western Mediterranean Sea ( San Martín, 2003), geographical areas far from Indonesia. However, we did not find any clear difference between the single specimen described above and the Mediterranean material. Some small variations have been found between the holotype and our specimen, e. g. dorsal cirri of holotype are slightly shorter in the anterior part, alternating in length (eight to nine articles the longest, and six to seven the shortest), while they are 12–13 in S. cf. cruzi and a pattern of alternating lengths has not been seen. The specimen from Indonesia is much longer (15 mm) than the holotype (5 mm). Examined specimens from the Mediterranean, which are longer (9 mm), have more articles in the dorsal cirri and in this respect more closely resemble the Indonesian specimen (10–12 the shortest and 16–18 the longest). It appears that the number of articles present on the dorsal cirri is related to body length; however, the alternation in length of dorsal cirri in the holotype could be a difference. Syllis cf. cruzi shows distinctive glands in the lateral and posterior margins of each segment, a character that was not described for the type material, not for any of the Mediterranean specimens of S. cruzi ( Núñez & San Martín, 1991; San Martín, 2003). However, we do not consider the presence of glands to be a useful diagnostic character; it might, for instance, appear only during the reproductive stage ( San Martín, 2003). More specimens would be needed to establish if the presence of glands and dorsal cirri, not alternating in length, are consistent characters and if so this could be useful to dis- Other species sharing a similar chaetal shape are Syllis lutea ( Hartmann-Schröder, 1960) (circumtropical), S. curticirris ( Hartmann-Schröder, 1981) (Atlantic Ocean) and Dentatisyllis carolinae ( Day, 1973) (Atlantic Ocean). Syllis lutea differs in having several longer distal spines on the edge of the blade (Hartmann- Schröder, 1960; Licher, 1999) while S. cf. cruzi only has one or two. Syllis curticirris has short dorsal cirri, with only three articles ( Licher, 1999; this study), while there are about 12–13 in S. cf. cruzi . Dentatisyllis carolinae has a trepan opening and the dorsal simple chaetae are distinctly bidentate ( Day, 1973; Uebelacker, 1984), whereas S. cf. cruzi has a smooth anterior margin and unidentate simple dorsal chaetae. Chaetae of Syllis gerundensis ( Alós & Campoy, 1981) (Mediterranean Sea) are also similar in shape, but spines on the edge of the blade are all short. In addition, dorsal cirri of this species are shorter, with five to seven articles on midbody ( Alós & Campoy, 1981; Licher, 1999). Syllis glandulata Nogueira & San Martín, 2002 ( Brazil) has similar glands on the lateral sides of each segment, but the spines of the compound chaetae are short ( Nogueira & San Martín, 2002).

Distribution. Indonesia. The nominal species occurs in the Atlantic Ocean (Canary Islands) and Western Mediterranean Sea.

Figures

FIGURE 10. Syllis cf. cruzi ZMA V. Pol. 5262. A: Anterior part, dorsal view; B: Anterior chaetae; C: Anterior aciculae; D: Dorsal simple chaeta; E: Ventral simple chaeta; F: Posterior chaetae; G: Posterior acicula. Scale A: 0.5 m; B – G: 20 µm.