Haplosyllis streptocephala ( Grube, 1857 ) Grube, 1857

Lattig, Patricia & Martin, Daniel, 2009, A taxonomic revision of the genus Haplosyllis Langerhans, 1887 (Polychaeta: Syllidae: Syllinae), Zootaxa 2220, pp. 1-40 : 29-30

Haplosyllis streptocephala ( Grube, 1857) new comb.

( Fig. 21 A–B)

Syllis streptocephala Grube, 1857: 1871 –182.— Horst, 1922: 196.— Perkins & Savage, 1975: 31.

Examine material. St. Croix, Caribbean Sea. Holotype ZMUC Pol–922.

Description. Body robust, length 2 cm, for 133 chaetigers, width 1 mm (excluding parapodia). Orangebrown. Prostomium subpentagonal, wider than long, with two pairs of small eyes in trapezoidal arrangement, difficult to see by pigment loss. Median and lateral antenna similar in size (17–19 articles), inserted on medium and anterior margin of prostomium, respectively. Palps twice as long as prostomium length, broadly triangular, fused at their bases, separated all along their length. Sensory organs of palps and nuchal organs not seen. Palps and prostomium much thinner than tentacular segment and subsequent chaetigers. Pharynx long, extending about 11 segments, obscured by body robustness; anterior tooth and papillae not seen. Proventricle cylindrical, dark-brown, extending 11 segments, with about 90 muscular cell-rows. Peristomium very short. Dorsal tentacular cirri long (17–21 articles), ventral ones broken. Dorsal cirri, tentacular cirri and antennae similar, whip-shaped. First dorsal cirri longer than remaining ones (28 articles), second short (14 articles), third and fourth slightly longer (20 and 24 articles, respectively), fifth short (15 articles), sixth slightly longer (19 articles); subsequent cirri do not exceed body width, with 13–21 articles, gradually decreasing to posterior end (9–13 articles). Ventral cirri digitiform, not longer than parapodial lobes. Anterior chaetae bidentate, with apical teeth equal in size; two or three chaetae per parapodia ( Fig. 21 A). Midbody chaetae broad, unidentate, but similar in shape to anterior ones ( Fig. 21 B); all chaeta with MJP long and straight; LMF shorter or similar than SW; US of MF without denticles. Three to five chaetae per parapodia. Pygidium broken.

Reproduction. Unknown

Host. The presence of spicules in the body of the holotype suggests a possible association with sponges.

Distribution. Caribbean Sea.

Remarks: Haplosyllis streptocephala was first described within the genus Syllis , but its chaetal shape agrees with Haplosyllis . Their chaetae are highly characteristic, broad and totally unidentate from medium body to posterior end. Both palps and prostomium are much thinner than the rest of the body, which distinguishes it from other Haplosyllis species. As the description is based only on the holotype, it is not possible to assess whether this is a species-specific characteristic (or a peculiarity of that particular specimen), as well as to provide ecological and reproduction data.

Figures

FIGURE 21. Holotype of Haplosyllis streptocephala. A—bidentate chaetae, anterior chaetiger; B—unidentate chaetae, midbody. Scale bar: 20 Μm.