Namalycastis fauveli Nageswara Rao, 1981

Ribeiro, Rannyele Passos, Alves, Paulo Ricardo, Almeida, Zafira da Silva de & Ruta, Christine, 2018, A new species of Paraonis and an annotated checklist of polychaetes from mangroves of the Brazilian Amazon Coast (Annelida, Paraonidae), ZooKeys 740, pp. 1-34 : 7-9

Namalycastis fauveli Nageswara Rao, 1981 Fig. 5

Type locality.

Estuary of Tachin River, Thailand (13°44'N, 100°30'E; original geolocation).

Material examined.

São Luís, 02°35'56"S, 44°21'11.8"W: one specimen, 6 September 2011 (NPM-Pol 883). Caranguejos Island, 02°49'33.6"S, 44°28'51.1"W: one specimen, 26 January 2011 (NPM-Pol 086); three specimens, 28 March 2011 (NPM-Pol 109); one specimen, 22 April 2010 (NPM-Pol 878); three specimens, 17 August 2010 (NPM-Pol 879); two specimens, 2 June 2012 (NPM-Pol 880); four specimens, 5 September 2011 (NPM-Pol 881). Complete and incomplete specimens.

Distribution.

Indian Ocean: Thailand, India. Atlantic Ocean: Brazil ( Maranhão state).

Diagnosis.

Body widest mid-anteriorly. Prostomium anteriorly shallowly cleft or cleft absent. Antennae minute. Notochaeta present. Heterogomph setae with boss extremely prolonged. Supra-neuroacicular falcigers in chaetiger 10 with blades slightly curved ( Glasby 1999).

Description.

Based on specimens NPM-Pol 878 and 883. Complete specimen with 17.3 mm long, 0.72 mm wide (chaetiger 10), and 79 chaetigers (Fig. 5A). Body widest mid-anteriorly, gradually tapering anteriorly and posteriorly. Dorsum convex. Epidermal pigment absent. Prostomium trapezoidal, some individuals with lateral indentation on pros tomium. Prostomium anterior end smooth or with a shalow cleft (Fig. 5B). Narrow longitudinal groove extending form tip to mid-posterior prostomium. Antennae short, extending short of palpophore anterior end, laterally inserted. Two pair of eyes transversally arranged on prostomium. Four pairs of tentacular cirri with indistinct cirrophores and smooth cir rostyles. Posterodorsal pair extending posteriorly to third chaetiger. Pharynx smooth, lacking paragnaths or papillae. Parapodia sesquirramous (sub-birramous). Dorsal cirri increasing in length posteriorly. Neuropodial acicular ligulae bilobed. Notochaeta as sesquigomph spinigers present from third chaetiger. Supra-acicular neurochaeta as sesquigomph spinigers on postacicular fascicle and heterogomph falcigers on preacicular fascicle (Fig. 5D, E). Sub-acicular neurochaetae as heterogomph spinigers on postacicular fascicle and heterogomph falcigers in preacicular fascicle. Supra-acicular sesquigomph spinigers shaft with boss 1.2 ×–1.5× length of collar. Shaft of heterogomph chaeta with boss prolonged. Supra-acicular falcigers in chaetiger 10 with blades slightly curved, blades length 8.0 ×–9.5× width of shaft head. Sub-acicular falcigers blades in chaetiger 10 length, 8.2 ×–11.4× (dorsal-most) and 6.0 ×–7.3× (ventral most) width of shaft head. Sub-acicular spinigers in anterior region of body with blades finely serrated. Chaeta pale. Aciculae dark brown. Pigidium buttom-shaped (Fig. 5C). Anus terminal. Anal cirri smooth and subconical, arising ventro-laterally.

Colour.

Specimens in alcohol yellow. No pigment visible throughout the body.

Remarks.

First species record for the America. These specimens present some differences from the original description ( Nageswara Rao 1981), such as a dorsal surface convex, body less arched mid-anteriorly, longer antennae and tentacular cirri (Fig. 2A). However, the projection of heterogomph chaetae with an extremely long boss supports this identification for this species (Fig. 2B, C). The differences found are probably because the specimens in this study are juveniles by the smaller size (around 15 mm long, and 80 chaetigers), compared to type material, 21-45 mm long, 134-282 chaetigers, after Glasby (1999). Some Namanereidinae species, as Namalycastis abiuma , can have juveniles with blades longer and up to 80 chaetigers. Namalycastis fauveli is recorded in estuarine beaches and coastal lagoons in the type locality ( Nageswara Rao 1981) and in mangroves of this study.