Haplosyllis djiboutiensis Gravier, 1900

Lattig, Patricia & Martin, Daniel, 2009, A taxonomic revision of the genus Haplosyllis Langerhans, 1887 (Polychaeta: Syllidae: Syllinae), Zootaxa 2220, pp. 1-40 : 18-20

Haplosyllis djiboutiensis Gravier, 1900

( Fig. 12 A–J)

Syllis (Haplosyllis) djiboutiensis Gravier, 1900: 147 –149, pl. 9, fig. 3.? Syllis (Haplosyllis) djiboutiensis.— Fauvel, 1919: 353.

Examined material. Djubal ("Gubal", saudi Arabia), Red Sea. Polytype MNHN 48.

Description. Polytype with anterior and posterior ends in poor conditions, body slender, length 8 mm, for 38 chaetigers, width 0.35 mm (excluding parapodia) ( Fig. 12 A), yellow-pale. Prostomium subpentagonal, wider than long, with two pairs of small red eyes in trapezoidal arrangement. Median (22 articles) and lateral (14 articles) antennae on medium and anterior margin of prostomium, respectively. Palps long, broadly triangular, fused at their bases, divergent all along their length. Cilia on palps and nuchal organs not seen. Pharynx orange, extending about five segments, anteriorly with large anterior tooth; ring of cilia and papillae cilia not seen. Proventricle cylindrical, dark-brown, length 0.45 mm, extending four segments, width 0.28 mm, with 36 muscular cell-rows ( Fig. 12 A). Peristomium similar in length to first chaetiger. Dorsal tentacular cirri longer than ventral ones (13–15 and 7–11 articles, respectively). Dorsal cirri slender, similar to antennae and tentacular cirri. First dorsal cirri longer than remaining ones (23 articles), second short (12 articles), third and fourth intermediate, longer than second (15 and 19 articles, respectively), fifth short (10 articles), sixth intermediate (15 articles). After proventricle, cirri alternating with long (7–9 articles) and short (4–5 articles); longest cirri do not exceed body width. Cirri broken at posterior end. Ventral cirri digitiform, anterior cirri longer than parapodial lobe, gradually shorter to posterior end ( Fig. 12 B–C). Chaetae all bidentate, anterior ones smaller, with short MF ( Fig. 12 D–E). Usually two chaetae on each midbody parapodia, different in size and shape; in largest chaeta LMF similar than SW; MJP straight and long; US of MF with denticles; distal tooth slightly shorter than posterior one ( Fig. 12 H), apparently very small when MF is in backward position ( Fig. 12 G). In smaller chaeta MJP short; proximal tooth smaller than distal one ( Fig. 12 I). Aciculae stout, with curved tip, upwards directed ( Fig. 12 F, G, J), two on each parapodia. Pygidium broken.

Host. There is no information on habitat and depth range for the types. However, Gravier (1900) originally described a sponge spicule as long aciculae, which suggest this species is associated with a sponge.

Reproduction. Unknown.

Distribution. Red Sea. Probably also in Madagascar, Fauvel (1919), but this record should be confirmed with examination of material.

Remarks. Haplosyllis uncinigera and H. djiboutiensis were considered as synonymous due their similarity of their chaetae ( Augener 1913). In the original drawing of H. djiboutiensis , chaetae appear to be as unidentate, very similar to ones of H. uncinigera . According to our observations, in the largest chaeta of H. djiboutiensis , the distal tooth is slightly smaller than proximal one, but usually, both teeth are clearly seen (except when main fang in in backward position, appearing to be unidentate), each parapodium has two aciculae, pharynx extends through 4–5 segments and the dorsum has a granulose aspect. In H. uncinigera , chaetae also have a unidentate appearance, but the angle between teeth is narrow and distal tooth very small, thin, making it difficult to observe, each parapodium has four to six aciculae, pharynx extends through 10 segments, and the dorsum do not has such granulose aspect. It is difficult to distinguish both species due the unidentate appearance of chaetae, and detailed examination of the distal tooth is required.

H. djiboutiensis is similar to H. granulosa and H. carmenbritoae but can be easily distinguished (see remarks of each species).

Specimens of Haplosyllis have been reported from different localities nearby the area of distribution of H. djiboutiensis as “ H. spongicola ”, such as the Red Sea ( Amoureux 1983; Hartmann-Schröder 1960), Madagascar ( Fauvel 1919) or the Suez Canal ( Fauvel 1927). In light of our results, these records must be regarded as doubtful unless material from these localities can be examined.

Figures

FIGURE 12. Polytype of Haplosyllis djiboutiensis. A—anterior end, dorsal view; B—anterior parapodium; Cmidbody parapodium; D—chaeta from chaetiger two; E—chaetae from chaetiger five; F—anterior acicula; G—largest chaeta, midbody, main fang in backward possition; H—largest chaeta, midbody; I—shortest chaeta, midbody; Jaciculae, midbody. Scale bars: A = 200 Μm; B – C = 50 Μm; D – J = 20 Μm.