Eusyllis liniata ( Hartmann-Schröder, 1962 ) Hartmann-Schroder, 1962

Fukuda, Marcelo V., Nogueira, João M. M. & Martín, Guillermo San, 2015, Eusyllinae and “ Incertae sedis ” syllids (Annelida: Syllidae) from South America, with a new species from Brazil and a new combination for a Peruvian species, Zootaxa 3936 (4), pp. 507-537 : 521

Eusyllis liniata ( Hartmann-Schröder, 1962) comb. nov.

Figure 8

Odontosyllis liniata Hartmann-Schröder, 1962: 125 –126, plate 9, figs 53–56; Verdes et al. 2011: 30 –32, fig. 2.

Material examined. Peru, Callao, between La Punta and El Camotal Island, on rhizoids of Macrocystis : 4 specs (paratypes, ZMH P- 19652), coll. Nodt, 29 May 1956; 3 specs ( ZMH P- 14758), coll. Nodt, 29 May 1956.

Description. Relatively small-sized body, largest fragment analysed with 22 segments, ~ 3 mm long, 0.35 mm wide. Faint pigmentation present on some specimens, as a discontinuous transverse dark stripe dorsally, at midlength of some anterior segments, more conspicuous close to bases of dorsal cirri, another longitudinal line dorso-laterally, close to each body lateral, and scattered dark spots on some cirri. Palps irregularly rounded, basally fused, ventrally bent to some extent. Prostomium ovate with 2 pairs of eyes in trapezoidal arrangement; antennae smooth to weakly wrinkled, lateral antennae inserted on anterior margin of prostomium, extending to almost twice length of palps; median antenna inserted more posteriorly, ~1/4 longer than lateral antennae. Peristomium shorter than subsequent segments; dorsal peristomial cirri up to same size as median antenna, ventral peristomial cirri approximately same size as lateral antennae. Dorsal cirri of chaetiger 1 usually longer than dorsal peristomial cirri; remaining dorsal cirri alternating longer cirri, as long as dorsal peristomial cirri, and shorter cirri, as long as ventral peristomial cirri. Antennae, peristomial and dorsal cirri with short cirrophores; cirrostyles distally pointing, lanceolate ( Fig. 8 A). Ventral cirri slightly longer than parapodial lobes on first chaetigers, as long as parapodial lobes on following ones, ovate. Parapodial lobes conical to slightly bilobed, posterior lobe longer. Anterior parapodia with ~20 falcigers each, midbody with 12–20; shafts of falcigers subdistally spinulated, with straight tips; connective between shafts and blades spinulated, more conspicuously in dorsalmost chaetae; blades of falcigers spinulated and unidentate to subbidentate ( Fig. 8 B–C); blades with inverted dorso-ventral gradation in length, ~10–15 Μm long. Dorsal simple chaetae present from right after proventricle chaetigers, thinner than shafts of falcigers, subdistally spinulated, bayonet-like shaped ( Fig. 8 D); ventral simple chaetae not observed. Anterior parapodia with up to 2 aciculae each, one of them distally irregularly blunt, other slightly enlarged distally, with one side more pronounced than other ( Fig. 8 E); midbody parapodia with 1 acicula each, thicker than on anterior body, subdistally bent, with rounded tip ( Fig. 8 F). Pharynx through 3–4 segments with large, conical central tooth close to opening and trepan with 12 teeth ( Fig. 8 G); proventricle through ~5 segments, with ~50 muscle cell rows ( Fig. 8 A).

Remarks. Eusyllis liniata comb. nov. was recently redescribed by Verdes et al. (2011) as Odontosyllis liniata but, for some features, such as the pharynx armature, the redescription was based in the original description ( Hartmann-Schröder 1962).

However, the trepan in Odontosyllis has teeth pointing backwards and lacks central pharyngeal tooth, which differs from the structure we have observed in the paratypes of E. liniata comb. nov., as well as from the trepan illustrated in the original description ( Hartmann-Schröder 1962, pl. 9, fig. 56).

Furthermore, other characters of E. liniata comb. nov. more closely resemble Eusyllis than Odontosyllis . Compared to the Brazilian species of Eusyllis , E. liniata comb. nov. presents falcigers resembling those of E. nonatoi sp. nov., except in the coarser spinulation on blades ( Figs 8 B–C and 9B–C), and thick, distally bent aciculae, similar to those of E. assimilis (see Figs 6 G and 8F). In addition, the bayonet-like dorsal simple chaetae of E. liniata comb. nov. resemble those of Eusyllis kupfferi Langerhans, 1879 (see San Martín & Hutchings 2006).

The holotype (ZMH P-14757) is possibly missing, since the vial was found empty.

Type locality. Peru—Callao (Pacific Ocean).

Distributon. Only known from Peru (Pacific Ocean).

Figures

FIGURE 6. Eusyllis assimilis. (A) anterior body, dorsal view; (B) falcigers, anterior and midbody; (C) falcigers, posterior body; (D) dorsal simple chaeta; (E) ventral simple chaeta; (F) aciculae, anterior body; (G) acicula, posterior body. Scale bars: A = 200 µm; B – G = 10 µm.

FIGURE 8. Eusyllis liniata comb. nov. (A) anterior body, dorsal view; (B) falcigers, anterior body; (C) falcigers, mid- and posterior body; (D) dorsal simple chaeta; (E) aciculae, anterior body; (F) acicula, posterior body; (G) detail of pharynx showing trepan. Scale bars: A = 200 µm; B – F = 10 µm; G = 20 µm.