Haplosyllis trifalcata ( Day, 1960 )

Lattig, Patricia & Martin, Daniel, 2009, A taxonomic revision of the genus Haplosyllis Langerhans, 1887 (Polychaeta: Syllidae: Syllinae), Zootaxa 2220, pp. 1-40 : 30-32

Haplosyllis trifalcata ( Day, 1960)

( Fig. 22 A–L)

Syllis trifalcata Day, 1960: 308 , fig. 6g –i

Syllis (Haplosyllis) trifalcata .— Day, 1967: 241, fig. 12 j–l. Haplosyllis trifalcata .— Licher, 1999: 284.

Examined material. South Africa. Holotype SAM A–20932, False Bay, 34º12’4’’S 18º43’5’0, 42 m.

Description. Holotype robust, length 1.3 cm for 89 segments. The specimen was in poor conditions, ventrally opened at anterior end. Preserved specimen Yellow-pale. Dorsal granules abundant on posterior segments, scarce from medium body to anterior end. Prostomium subpentagonal, wider than long, with two pairs of small red eyes in trapezoidal arrangement. Antennae broad, short; median antenna slightly longer (14 articles) than lateral ones (10 articles), inserted on medium and anterior margin of prostomium, respectively. Palps broad ventrally bent behind proventricle ( Fig. 22 A). Cilia on palps and nuchal organs not seen. Pharynx orange, length 1.1 mm, extending 8–9 segments, width 0.2 mm; anteriorly, with large tooth; papillae not seen. Proventricle dark-brown, length 0.28 mm, extending 5–6 segments, width 0.93 mm, with 35 muscular cellrows. Peristomium well defined, shorter than subsequent ones. Dorsal tentacular cirri longer than ventral ones (12 and 9 articles, respectively). Dorsal cirri similar to antennae and tentacular cirri, long and broad. Dorsal anterior cirri similar in length: first with 13 articles, second with 11 articles, third broken, fourth with 13 and fifth with 10; midbody dorsal cirri not as broad as anterior ones, with 7–13 articles, gradually shorter to posterior end; posterior cirri short (1–4 articles). Ventral cirri digitiform, anterior ones longer than midbody and posterior ones ( Fig. 22 B, C, D). Chaetae most frequently bidentate, three to six per parapodia, similar all along body; apical teeth long and wide; MJP very short, curved; MF very close to apical teeth, giving a tridentate appearance; LMF shorter than SW, without spines on its US ( Fig. 22 E–G). In posterior-most chaetigers, one chaeta with three apical teeth, MF apparently lacking, with a transversal incision below the tridentate cusp ( Fig. 22 H); one simple bifid chaeta on posterior-most parapodia ( Fig. 22 I). Anteriorly, two small aciculae, one with straight rounded tip, other with slightly curved upwards directed tips ( Fig. 22 J). One orange, broad, with curved tip downwards directed tip at midbody ( Fig. 22 K), and one with slightly curved tip on the most posterior segments ( Fig. 22 L). Pygidium with two long anal cirri (12–13 articles).

Reproduction. Unknown.

Host. Unknown.

Remarks. Haplosyllis trifalcata was originally described as having 3–6 simple chaetae on each parapodium, all them similar, with three claw-like teeth; this apparently tridentate chaetae is the most frequent type in the holotype ( Fig. 22 E–G). However, there is an additional chaeta on the most posterior parapodia, showing a transversal incision below the tridentate cusp ( Fig. 22 H). This lead us to postulate that the origin of these tridentate chaetae may result from the fusion of blade and shaft, as suggested for other Haplosyllis species (see remarks on H. spongiphila ). By homology the presence of the incision supports that the third “tooth” is an upwards-directed MF instead of an additional apical teeth.

The holotype was ventrally dissected, affecting its original shape and making it difficult to determine its proportions.

Figures

FIGURE 22. Holotype of Haplosyllis trifalcata. A—anterior end, dorsal view; B— anterior parapodium; C—midbody parapodium; D—posterior most parapodium; E, F, G—anterior, midbody and posterior bidentate chaetae, respectively; H—tridentate chaeta, posterior parapodia; I—simple chaeta, posterior most parapodia; J, K, L—anterior, midbody and posterior aciculae, respectively. Scale bars: A = 200 Μm; B – D = 100 Μm; E – L = 20 Μm.