Description. Body elongated, flattened dorsoventrally, subrectangular in cross-section; 2 mm in length, including palps and pygidial cirri; 26 chaetigerous segments, and pygidium (Figure 2 a-b). Prostomium bilobed, rounded to hexagonal, lateral antenna with terminal insertion (Figure 3 a). Two pairs of eyes; anterior pair dorsolateral, near widest portion of prostomium, posterior pair near posterior end of prostomium, converging towards midline, buccal segment without nuchal fold, but with pair of nuchal nodules (Figure 3 a-b). Median and lateral antennae, tentacular and dorsal cirri with two dark rings (Figure 2 a), both having subdistal swelling, culminating abruptly in sharp point; ceratophores cylindrical, median antenna larger than lateral antennae. Pair of palps, slightly smaller than median antenna, culminating in thin point, with 8 longitudinal rows of papillae. Tentacular segment with two pairs of cylindrical tentaculophores, with three prostomial chaetae on anterodorsal bases. Buccal cirri larger than ventral cirri, with cylindrical cirrophores. Pharynx with nine pairs of papillae and two pairs of maxillae. Facial tubercle present. Dorsal cirri with same coloration as median antenna, larger than ventral cirri, with cylindrical cirrophores. Parapodia biramous (Figure 3 b), prechaetal lobe quadrate or subtriangular, postchaetal lobe short and subtriangular, both with acicula; short notopodia on anterodorsal side of neuropodia. Notochaetae spinous, superior row slender, serrated on convex side (Figure 3 c). Neuropodia large, truncate, distally cleft with prechaetal lobe slightly longer than poschaetal lobe. Neurochaetae stouter than notochaetae, falcate, subdistally thickened, with several rows of spines, distal spines usually much larger than basal ones, and bidentate tips with small secondary tooth (Figure 3 d). Twelve pairs of elytra, covering dorsum entirely, with dark-brown pigmentation; pairs until last chaetiger segment following order: 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21 and 23; long papillae along external edge. First three pairs of elytrae more ornate, with tubercles (Figure 3 e); on 11 th and 12 th pair with ornamentation similar to that in first pair. Most carinate macrotubercles in central region (Figure 3 f-g), surrounded by microtubercles (Figure 3 h); after 4 th or 5 th pair (Figure 3 i), small warty tubercles give impression of smooth elytra (Figure 3 j). Nephridial papillae starting from chaetiger 7, with peduncular aspect. Short ventral cirri with thin tip; pair of long anal cirri with same coloration as median antenna; dorsal anus in last chaetiger segment (Figure 2 b).
Sumber: A catalogue of the scaleworm genus Lepidonotus (Polynoidae, Polychaeta) from South America, with two new records for Brazilian waters