Prosphaerosyllis battiri n.sp.

Figs. 28A–H, 29A–F

Material examined. AUSTRALIA: WESTERN AUSTRALIA. HOLOTYPE: AM W26802, outer Ningaloo Reef, off Ned’s Camp, Cape Range National Park, 21°59.5'S 113°54.5'E, airlift from living Porites sp., 2 m, R.T. Springthorpe & J.K. Lowry, 1 Jan 1984. PARATYPES: 2 specimens (1 specimen on SEM stub), AM W27667, inshore reef, Ned’s Camp, Cape Range National Park, 21°59'S 113°55'E, very fine sediment and sand from patches in reef, 1 m, H.E. Stoddart, 2 Jan 1984.

Description. Body short, holotype mature male with natatory chaetae from chaetiger 8 to 23, 2.72 mm long, 0.27 mm wide, 28 chaetigers. Prostomium oval to pentagonal, slightly larger than long, contracted on anterior segments but not covered by them (Figs. 27A, 28B); 4 large eyes in trapezoidal arrangement and 2 anterior eyespots. Antennae all similar, small, mamilliform; median antenna inserted between posterior eyes, lateral antennae inserted in front of anterior eyes, slightly posteriorly to eyespots (Fig. 28A). Palps short, fused all along their length except for a terminal notch, provided with distinct papillae (Fig. 28A). Peristomium small, short, indistinct, covering posterior margin of prostomium (Figs. 28A, 29B); tentacular cirri similar to antennae but smaller (Figs. 28A, 29B), similar to papillae. Dorsum and ventrum covered by large, round papillae, forming 3–4 irregular transverse rows, giving a rough appearance (Fig. 29A), especially on anterior half of body (Figs. 28A, 29B), papillae less numerous on posterior half of body (Figs. 28B, 29D). Dorsal cirri on all parapodia, short, mamilliform (Fig. 29C) to lemon-shaped on anterior parapodia (Figs. 28A, 29B), longer and larger on posterior half of body, dilated basally, provided with a distinct, retractile cirrostyle (Figs. 28B, 29C). Compound chaetae provided with short, falcate, unidentate blades, with short marginal spines of anterior parapodia (Figs. 28D, 29E,F), smooth on remaining parapodia (Fig. 28F); anterior parapodia each with 5 compound chaetae, blades 6–4 µm long, posterior parapodia each with 4 compound chaetae, blades all about 4.5 µm long. Dorsal simple chaetae from chaetiger 1, unidentate, nearly smooth on margin (Fig. 28C,E). Ventral simple chaetae on posterior parapodia, sigmoid, smooth, unidentate (Fig. 28G). Acicula solitary, slender, acuminate (Fig. 28H). Pharynx through about 4–5 segments; pharyngeal tooth large, rhomboidal, located in anterior half pf pharynx (Fig. 28A). Proventricle through 3 segments, with about 26 muscle cell rows.

Remarks. Prosphaerosyllis battiri n.sp. is characterized by having palps not totally fused, prostomium not retracted on peristomium or only slightly retracted, the shape of dorsal cirri and the arrangement of papillae, which are numerous anteriorly and less numerous on posterior segments. It appears to resemble Prosphaerosyllis semiverrucosa Ehlers, 1913, but the arrangement of dorsal papillae is reversed, being more or less smooth on anterior segments and rough on posterior half of body (Ehlers, 1913; Day, 1967); I have examined one posterior piece of one specimen of S. semiverrucosa (ZHM P-14615) and it agrees perfectly with Ehlers’ and Day’s descriptions, with numerous dorsal papillae.

Distribution. Australia (Western Australia).

Habitat. On corals and sediments in shallow water.

Etymology. From the Aboriginal name battiri, meaning rough.