Haplosyllis basticola Sardá, Ávila & Paul, 2002

Lattig, Patricia, Martin, Daniel & Martín, Guillermo San, 2010, Syllinae (Syllidae: Polychaeta) from Australia. Part 4. The genus Haplosyllis Langerhans, 1879, Zootaxa 2552 (1), pp. 1-36 : 4-6

Haplosyllis basticola Sardá, Ávila & Paul, 2002

Figs 1A–G , 2A–D , 3A–D

Haplosyllis basticola Sardá et al. 2002: 168–171 , figs 1–2.— Lattig & Martin, 2009:11–12 , figs 6–7.

Haplosyllis spongicola: Magnino et al. 1999 : figs 11–12.

Examined material. AUSTRALIA: NEW SOUTH WALES. 18 specimens AM W29374 (plus 3 specimens mounted for SEM), 100 m south of Split Solitary Island , 30º15'S 153º10'30''E, 16 m, sponge attached to rocky bottom, coll . R. T. Springthorpe , 23 June 1992 . 3 specimens, AM W 26340, 100 m north west of Split Solitary Island , 30º14'0''S 153º10'48''E, 17 m, mixed red algae, coll . S. J. Keable , 7 March 1992 .> 100 specimens AM W26384 (plus 2 specimens mounted for SEM), Gap Bluff , 33°50'43''S 151°17'09''E, 20 m, in unidentified Ianthellidae sponge with spikey surface, dark reddish black in colour, coll . K. B. Attwood and G. San Martín , 14 June 2000 .

Additional material: PAPUA NEW GUINEA: BISMARK SEA, LAING ISLAND. 04°09'S 114°52'E, inside Anomoiantella lamella , 15 m, coll . R. Danovaro & S. Fraschetti, 12 August 1986. Personal collection, D. Martin .

Comparative material: ISLAND OF GUAM, MICRONESIA. 20 Paratypes of H. basticola MNCN 16.01/8439 .

Description. Body fragile, translucent, small, 2.5–4.5 mm long for 15–33 segments, 0.15–0.4 mm wide excluding parapodia, widest at proventricle level ( Figs 1A , 2A ). Preserved specimens pale yellow to brown purple. Small dorsal granules throughout body. Dorsal pigment pattern absent. Prostomium subpentagonal, wider than long, with two pairs of small red eyes in trapezoidal arrangement. Median antennae inserted on middle of prostomium, between eyes (8–28 articles); lateral antennae on anterior margin (6–14 articles). Palps long, broadly triangular, fused at their bases but separated all along their length; sensory organs as rows of cilia on ventral upper side. Nuchal organs not seen. Pharynx orange, extending through about four segments; with a large anterior tooth, crown of 10–12 soft papillae and inner ring of cilia ( Fig. 2B ); upper side of papillae with groups of cilia making up the sensory organs. Proventricle cylindrical, dark brown, extending through 2–4 segments, with 30–35 muscle cell rows ( Fig. 1A ). Peristomium well defined, shorter than subsequent segments. Dorsal tentacular cirri longer than ventral ones (10–18 and 2–8 articles, respectively). Dorsal cirri slender, similar to antennae and tentacular cirri. Anterior cirri long, alternating in length as follows: first cirri long (10–28 articles); second short (3–14 articles), third and fourth progressively longer (4– 14 and 5–19 articles, respectively) and fifth small (2–10 articles). After proventricle, longest cirri does not exceed half of body width, gradually decreasing in length toward posterior end (2–6 articles) ( Fig. 1B ). Ventral cirri digitiform, anterior ones slender, longer than parapodial lobes; median and posterior ones gradually decreasing in length ( Figs 1C–D ). Chaetae all bidentate, 1 – 3 per parapodia, stout, broad, all similar in shape but anterior ones slightly smaller; LMF similar in length to SW; MJP short, curved; US of MF without denticles; apical teeth similar in length ( Figs 1E – F , 2C – D ). All parapodia with one stout acicula, with slightly upwards-directed curved tip ( Fig. 1G ).

Reproduction. The reproductive bodies of Haplosyllis basticola are cephalic stolons. Both male and female stolons have 10–12 chaetigers, a well defined head with two small antennae and two pairs of reddish eyes, and long swimming chaetae ( Fig. 3A–D ).

Ecology. Haplosyllis basticola has been found only on sponges of family Ianthellidae , such as Ianthella basta (Pallas, 1776) from Micronesia ( Sardá et al. 2002), Anomoianthella lamella Pulitzer-Finali & Pronzato, 1999 from Papua-New Guinea ( Magnino et al. 1999), and an unidentified species from Australia. Nevertheless, it is not possible to confirm if H. basticola is a specific endobiont of iantellid sponges due to the absence of host sponge identifications for most of the Australian material cited here.

Remarks. The Australian specimens differ from the type population ( Micronesia) in size, reaching up to 33 segments and up to 25 segments, respectively. Similar differences occur for the cirri length, especially in the anterior ones, which are smaller in Micronesian than in Australian specimens. Additionally, the specimens from Micronesia, Papua-New Guinea, and some of the Australian populations were violet or brown purple (even preserved), mimicking the colour of the respective host sponges. The other Australian populations had creamy-yellow bodies. Despite the differences in size, the stolons, aciculae and chaetae were identical in all populations, the latter being the most diagnostic feature for the identification of H. basticola .

Distribution. AUSTRALIA (New South Wales); MICRONESIA (Island of Guam); PAPUA-NEW

GUINEA (Laing Island, Bismark Sea).

Figures

FIGURE 1. Haplosyllis basticola. A—anterior end, dorsal view, with everted pharynx; B—posterior end, dorsal view; C—anterior parapodium; D—posterior parapodium; E—anterior chaetae; F—posterior chaeta; G—posterior acicula. Scale: Α–Β = 250 µm; C–D = 80 µm; E–G = 20 µm. 1 specimen (AM W29374).

FIGURE 2. SEM micrographs of Haplosyllis basticola. A—whole body, dorso-lateral view; B—anterior end, showing everted pharynx; C—anterior chaetae; D—median chaeta. Scale: A = 1 mm; B = 100 µm; C–D = 50 µm. Two specimens (AM W29374).

FIGURE 3. Female reproductive body of Haplosyllis basticola. A—whole body; B—anterior end showing head and two antennae; C—parapodium showing swimming chaetae; D—anterior end, showing oocytes (by transparency), swimming chaetae, antennae and reddish prostomial eyespots. A–C: SEM micrographs. Scale: A = 600 µm; B = 100 µm; C = 50 µm; D = 600 µm. Specimens from Papua New Guinea (D. Martin, Personal collection).