Salvatoria pilkena, Guillermo San Martin, 2005

Guillermo San Martin, 2005, Exogoninae (Polychaeta: Syllidae) from Australia With the Description of a New Genus and Twenty-two New Species, Records of the Australian Museum 57, pp. 39-152 : 58

Salvatoria pilkena n.sp.

Fig. 14A–J

Material examined. AUSTRALIA: QUEENSLAND. HOLOTYPE: 1 specimen, AM W26886, Hinchinbrook Channel, 18°20'S 146°4'E, tidal mud- and sandflats, S. Dittmann, 22 Oct 1991. PARATYPE: 1 specimen, AM W27676, Hinchinbrook Channel, 18°20'S 146°4'E, tidal mud- and sandflats, S. Dittmann, 22 Oct 1991.

Description. Body small, holotype 2.2 mm long, 0.16 mm wide, 24 chaetigers. Prostomium ovate, distinctly wider than long; 4 eyes in trapezoidal arrangement, anterior eyespots not seen. Antennae small, rugose, more or less spindle-shaped; median antenna inserted between posterior eyes, similar in length to combined length of prostomium and palps, lateral antennae shorter than median antenna, inserted in front of anterior eyes. Palps shorter than prostomium, dorsally fused by a thin membrane, with a distal notch ( Fig. 14A ). Two distinct ciliated nuchal organs between prostomium and peristomium; peristomium similar in length to following segments, tentacular cirri similar to antennae, dorsal tentacular cirri similar in length to lateral antennae, ventral ones shorter. Dorsal cirri similar to antennae and tentacular cirri, lacking on chaetiger 2 ( Fig. 14A ); dorsal cirri of chaetiger 1 longer than remaining, similar in length to median antenna, all other dorsal cirri relatively short, some longer on posterior parapodia ( Fig. 14B ). Ventral cirri short, digitiform, those of posterior parapodia slightly longer. Parapodia ending, as typically other species of the genus, in 3 distinct rounded papillae ( Fig. 14F ). Compound chaetae with smooth, slender shafts and blades; blades bidentate, both teeth acute, subdistal tooth shorter than distal tooth, provided with moderately long spines, upwards pointed; on bases of longer blades, distal half of margin smooth or provided with small spines. Anterior parapodia each with about 6 compound chaetae, strong dorsoventral gradation in length of blades ( Fig. 14E ), 24 µm above, 8 µm below, longer blades with a double curvature; posterior parapodia each with only 4 compound chaetae, less marked dorsoventral gradation ( Fig. 14H ), 20 µm above, 14 µm below. Dorsal simple chaetae from chaetiger 1, smooth, slender, apparently unidentate ( Fig. 14C,G ). Ventral simple chaetae only present on most posterior chaetigers, sigmoid, smooth, strongly bidentate ( Fig. 14I ). Acicula solitary, acuminate ( Fig. 14D ). Pharynx long, through about 4 segments; pharyngeal tooth small, located near anterior margin. Proventricle similar in length to prostomium, through 3 segments, with about 18 muscle cell rows. Pygidium small, slightly bilobed, with 2 anal cirri, similar to dorsal cirri.

Remarks. Salvatoria pilkena n.sp. belongs to a small group of species with rugose dorsal cirri, different from the typical spindle-shaped typical of the genus, and lacking dorsal cirri on chaetiger 2. Salvatoria swedmarki ( Gidholm, 1962) and S. celiae (Parapar & San Martín, 1992) are similar, but they differ from S. pilkena in having much longer proventricles and in the compound chaetae, which are short and unidentate in S. swedmarki and strongly bidentate, with long marginal spines of blades in S. celiae (see Gidholm, 1962; Parapar & San Martín, 1992; and San Martín, 2003). The described and figured specimen of S. opisthodentata by Hartmann-Schröder (1991) has similar compound chaetae and body but it is figured as having dorsal cirri on chaetiger 2; this specimen has been examined and lacks dorsal cirri on chaetiger 2.

Distribution. Australia (Queensland).

Habitat. Tidal mud and sand flats.

Etymology. The specific name is an Aboriginal word, pilkena , meaning “different”, because of the unique features.

Figures

Fig. 14. Salvatoria pilkena n.sp. (A) anterior end, dorsal view of holotype. (B) posterior end, dorsal view. (C) dorsal simple chaeta, anterior parapodium. (D) acicula, anterior parapodium. (E) compound chaetae, anterior parapodium. (F) parapodial lobe, midbody, dorsal view. (G) dorsal simple chaeta, posterior parapodium. (H) compound chaetae, posterior parapodium. (I) ventral simple chaeta, posterior parapodium. Scale A–B: 0.16 mm, C–J: 20 µm.