Lepidonotus natalensis Day, 1951

De Assis, Jose Eriberto, de Brito, Rafael Justino, Christoffersen, Martin Lindsey & de Souza, Jose Roberto Botelho, 2015, A catalogue of the scaleworm genus Lepidonotus (Polynoidae, Polychaeta) from South America, with two new records for Brazilian waters, ZooKeys 533, pp. 63-98 : 68-72

11. Lepidonotus natalensis Day, 1951 Figures 4, 5

Lepidonotus natalensis Day, 1951; fig. 1 e-l [removed from synonymy with Lepidonotus tenuisetosus (sensu Day 1967)].

Lepidonotus tenuisetosus Fauvel, 1927: 414 [not Gravier, 1902].

Diagnosis.

Without nuchal fold; some elytrae with group of papillae in center, dark pigmentation and small tubercles after 4th or 5th pair, giving impression of smooth elytra; elytra margin and surface with long slender, digitiform papillae; notochaetae partially threadlike; neurochaetae unidentate.

Description.

Body elongate, flattened dorsoventrally; with 26 chaetigerous segments, 2 mm in length, including palps and pygidial cirrus, 2 mm in width, including chaetae (Figure 4a-b). Dorsum and sides of parapodia pigmented black. Prostomium bilobed, rounded, slightly hexagonal, black pigmentation at base of ceratophores (Figure 5a). Lateral antenna with terminal insertion; two pairs of eyes, anterior pair dorsolateral, near widest portion of prostomium, posterior pair near base of prostomium, converging towards midline (Figure 5b). Median and lateral antennae, tentacular and dorsal cirri with two dark rings; first more elongated than second, both having subdistal swelling, culminating abruptly in sharp point; ceratophores cylindrical, median antenna larger than lateral antennae. Palps paired, same length as median antenna, culminating almost abruptly into 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 9 pairs of papillae and 2 pairs of maxillae. Facial tubercle present. Dorsal cirri with same coloration as median antenna, larger than ventral cirri, with cylindrical cirrophores.

Parapodia biramous (Figure 5c), 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, partially thread-like, with fine, pointed tips (Figure 5d). Neuropodia large, truncate, distally cleft, with prechaetal lobe slightly longer than poschaetal lobe. Neurochaetae stouter than notochaetae, falcate, subdistally slightly thickened, with few rows of spines below slightly bent, blunt, unidentate tips (Figure 5e).

Twelve pairs of elytra covering dorsum entirely, with dark or dark-brown pigmentation; pairs until last chaetiger segment following order: 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21 and 23. First three pairs more ornate, with macro and microtubercles (Figure 5f-h); these tubercles located more posteriorly on elytra after 4th or 5th pair, giving impression of smooth elytra; on 11th and 12th pairs ornamentation similar to that in first pairs. Most of macrotubercles on central region, surrounded by microtubercles (Figure 5i-j). Very long digitiform papillae along external edge, and group of papillae near inferior base of elytra or sometimes next to center (Figure 5k).

Nephridial papillae starting from chaetiger 7, with peduncular aspect. Short ventral cirri with thin tip; one pair of short anal cirri with same coloration as median antenna; anus dorsal in 23rd chaetigerous segment (Figure 4b).

Habitat.

Intertidal zone (algae, rhodoliths) to 5 m, from the coast of Paraíba.

Holotype.

BMNH 1961.16.1

Type locality.

Natal, South Africa.

Distribution.

Suez Canal, Arabian Sea: Karachi; Port Edward, Natal, South Africa, Indian Ocean ( Day 1951; Wehe 2006).

New records.

Barra de Camaratuba, Mataraca, Paraíba, Brazil (06°36'14.17"S, 34°57'48.79"W).

(POLY- UFPB 1504), adult from Barra de Camaratuba, Mataraca (06°36'14.17"S, 34°57'48.79"W), Paratypes (POLY- UFPB 1505, 1506), Prainha, Baía da Traição (06°41'23.77"S, 34°55'48.47"W), Paraíba, Brazil.

Remarks.

Lepidonotus natalensis presents a wide distribution. Futher studies are required to enable us to understand if it is a cryptogenic species, because there are no studies to show that it is a species complex, and its origin was not determined.