Haplosyllis tenhovei Lattig, Martin & Aguado 2010

Figs 18A–F, 19A–F, 20A–G, 21A–D

Haplosyllis tenhovei Lattig et al. 2010: 795-796, fig. 8.

Examined material. AUSTRALIA. NEW SOUTH WALES: 10 specimens AM W26629 (plus 2 specimens mounted for SEM), south west of Bowen Island, 35º7'49''S 150º45'77''E, ramified yellow sponge, 5 m, 8 December 1993, coll. P. Servo and G.D. Wilson. 2 specimens AM W26336, north east of Bowen Island, Jervis Bay, 35º07'S, 150º46'E, 36 m, clumps of ascidians and bryozoans, 31 May 1987, coll. P.A. Hutchings and P.B. Berents. 3 specimens AM W36598 (plus 1 specimen mounted for SEM), 150 meters east of Burrill Rocks, 35°23'25''S 150°28'11''E, 17 m, dead bryozoan encrusted with algae, 1 May 1997, coll. K.B. Attwood. TASMAN SEA: 5 specimens AM W36599, Taupo Seamount, 33º14'13''S 156º10'41''E, 133 m, coll. J.K. Lowry, 2 May 1989. Haplosyllis cf. tenhovei: WESTERN AUSTRALIA. 1 specimen AM W36600 (plus 1 specimen mounted for SEM), Goss Passage, Beacon Island, 28º25'30''S 113º47''E, 33 m, dead coral, embedded in fine sediment, coll. P.A. Hutchings, 23 May 1994. 1 specimen AM W36616, north end of Long Island, Goss Passage, 28º27'54''S 113º46'18''E, 6 m, dead coral covered in coralline and brown algae, coll. C. Bryce, 22 May 1994. NORTHERN TERRITORY: 1 specimen AM W36617 Darwin Harbour, East Point, 12°24'36''S 130°39'57"E, 10 m, dead coral rubble and algal washings, coll. P.A. Hutchings, 17 July 1993.

Description. (Measurements in parenthesis for juveniles).

Body strong, small, 3–6 (1.5–1.7) mm long for 25–42 (17–20) segments, less than 1 mm wide excluding parapodia, widest at proventricular level (Fig. 19C); pale yellow, with some cirri having brownish round spots. Dorsal granules and pigment pattern absent. Prostomium subpentagonal, wider than long, with two pairs of small red eyes in trapezoidal arrangement (Fig. 18A–B). Median antennae inserted on middle of prostomium, between eyes, twice as long as lateral ones, with 16–29 (10–16) articles; lateral antennae inserted on anterior prostomial margin, with 10–16 (6–13) articles. Palps long, slightly longer than prostomium, broadly triangular, fused at their bases. Sensory organs of palps and nuchal organs not seen. Pharynx orange, extending through 5–7 (3–4) segments; with large triangular anterior tooth, crown of about 10 soft papillae and inner ring of cilia (Fig. 19B). Ventral side of papillae with rows of cilia making up sensory organs. Proventricle cylindrical, dark-brown, long, extending through 6–10 (3–6) segments, with 35–40 (22–26) muscle cell rows. Peristomium well defined, shorter than subsequent segments. Dorsal tentacular cirri longer than ventral ones, with 15–24 (10–17) and 7–18 (3–13) articles respectively. Antennae, tentacular cirri and dorsal cirri similar, long and slender. Anterior dorsal cirri long, with a well-defined length pattern: first cirri slightly longer than body width, longer than remaining ones, with 21–29 (12–18) articles, second shorter, 9– 13 (3–7) articles, third and fourth intermediate, gradually longer than second, with 11–19 (3–10) and 15–26 (2–13) articles respectively, fifth shorter, 9–15 (2–7) articles, sixth intermediate, with 14–23 (3–8) articles. Thereafter, cirri slightly alternating with long (13–24 articles, almost as long as body width) and short (6–15 articles), gradually decreasing in length towards posterior end. Ventral cirri digitiform, anterior ones as long as parapodial lobes; median and posterior ones shorter. Chaetae all bidentate, 2–3 per parapodia, similar throughout, anterior ones slightly smaller (Figs 18C; 19D); LMF similar in length to SW; MJP short, curved and relatively long; US of MF with a long denticle and few smaller ones toward the tip; apical teeth similar in length, long, well separated (Figs 18D; 19E–F). Aciculae straight broad, with rounded tips (Fig. 18E–F), 2–3 per anterior and median parapodia, one in the posterior end. Pygidium not seen.

Reproduction. Not known.

Distribution. INDONESIA (Komodo and Karang Kaledupa Islands). AUSTRALIA (New South Wales, Western Australia and Northern Territory).

Remarks. The original description of H. tenhovei is here complemented with the description of the long denticles on the US of MF, the sensory organs on the pharyngeal papillae and the nuchal organs. Some small specimens, likely juveniles, (AM W36629) had shorter and broader cirri than those of adults, but all chaetal features remain identical (Figs 18B; 19A, D).

Haplosyllis tenhovei resembles H. sandii sp. nov., in body shape and cirri length, but differs in the acicular shape (straight in the former, with curved tip in the latter).

A few specimens are herein considered as Haplosyllis cf. tenhovei (see examined material) due their slender bodies (Figs 20A–B; 21A), but more importantly, by the presence of a small slender, simple chaetae on the posterior last 1–4 segments (Figs 20E; 21D), resembling that described by Imajima (1966, fig. 43f), and never seen in any other Haplosyllis species. However, those specimens are not considered as a new species due to their chaetal and acicular shapes (Figs 20C–D, F–G; 21B–C) being very similar to those of H. tenhovei, the most characteristic features of the species. Furthermore, the length of their dorsal cirri, pharynx and proventricle, agree with the same measured values in specimens of H. tenhovei.