Nicomache (Nicomache) brasiliensis, Assis, José Eriberto De, Samiguel, Carmen Alonso & Christoffersen, Martin Lindsey, 2007

Assis, José Eriberto De, Samiguel, Carmen Alonso & Christoffersen, Martin Lindsey, 2007, Two new species of Nicomache (Polychaeta: Maldanidae) from the Southwest Atlantic, Zootaxa 1454, pp. 27-37 : 33-35

Nicomache (Nicomache) brasiliensis sp. nov.

( Fig. 2 A–J)

Material examined. Holotype: Adult female, Ponta do Cabo Branco beach (07°09'06''S; 34°47'00''W), João Pessoa, Paraíba, Brazil (CIM-POL-UFPB 111). Paratype: Same locality ( CIM-POL- UFPB 112).

Diagnosis. Prostomium rounded anteriorly, long, forming a low straight keel that becomes larger posteriorly; nuchal grooves straight, pointed anteriorly. A very thin furrow is present behind the prostomium. Colour uniformly light pink. Four to six acicular spines on setigers 1–3 (1: 4, 2: 4, 3: 6). Posterior end terminating in anal funnel, bordered by about 24 similar anal cirri.

Description. Body complete, with 22 setigers and two pre-anal asetigerous segments. Body 120 mm long. Setigers 1–4 with 3 mm wide; subsequent segments up to 5 mm wide. Posterior region with 2 pre-anal asetigerous segments and anal funnel 3.5 mm long. Prostomium fused to peristomium, with a well-defined head. Prostomium rounded anteriorly, forming a low, straight, subterminal keel, becoming broader posteriorly ( Fig. 2 A).

Two parallel nuchal grooves present on either side of prostomium, each with a sharp anterior angle ( Fig. 2 B). Peristomium with a narrow furrow extending from one side of mouth to the other, passing over dorsal region, behind prostomium. Ocelli and pigment spots absent. Mouth ventral, with narrow lips and a few crenulations surrounding mouth.

Neuropodia of setigers 1–3 with yellow strong sharp acicular spines (1: 4; 2: 5; 3: 6) ( Fig. 2 C). Neuropodia of setigers 4–22 with a simple row of rostrate uncini. Each uncinus with a main fang, 5–7 accessory teeth, and a subterminal tuft of five long, thin fibrils below fang; long anterior shaft, with an indistinct manubrium and less curved posterior shaft ( Fig. 2 D, 2E); all uncini are light-yellow. From setiger 4, neuropodia with a variable number of uncini: 4: 27, 5: 33, 6: 43, 7: 43. Notopodia of setigers 1–22 with fascicles of three kinds of capillary setae: long, smooth, with strong, yellow, transparent shaft ( Fig. 2 F); long, bristled, with simple or sometimes bifurcate tips, strong and dark-yellow shaft ( Fig. 2 G); and smooth unilimbate, with margins hatched, and with very narrow apices, shaft strong, yellow, transparent ( Fig. 2 H).

Two pre-anal asetigerous segments are present. Posterior end ending in an anal funnel, bordered by 21 similar anal cirri ( Fig. 2 I); anus terminal, located on an elevated mound ( Fig. 2 J).

Tube 170 mm long, composed of sand grains, fragments of urchin spines and pieces of mollusk shells pasted onto a thin, very resistant yellow membrane.

Habitat. Tubes under stones in the intertidal region.

Etymology. The new species is dedicated to the country in which it was discovered.

Remarks. Nicomache (Nicomache) lanai sp. nov. differs from N. (Nicomache) brasiliensis sp. nov. by having a prostomium with a tall and arched cephalic keel, elliptical nuchal grooves that open posteriorly ( Fig. 1 A), 4–7 acicular spines on setigers 1–3, and by having a cup-shaped anal funnel with concave sides. N. (Nicomache) antillensis differs from N. (Nicomache) brasiliensis sp. nov. by having a prostomium with a rounded, low dorsal keel, nuchal grooves nearly perpendicular to the keel, with a slight curve at the apex in the form of an inverted V, and by having 3–5 acicular spines in setigers 1–3. The latter species are similar in the form of the anal funnel, being bordered by cirri of similar sizes ( Augener 1922; Treadwell 1924; Jiménez- Cueto & Salazar-Vallejo 1997). N. (Nicomache) lumbricalis differs from N. (Nicomache) brasiliensis sp. nov. by having a prostomium with a hook-like projection over the mouth, nuchal grooves as long, parallel slits with their anterior ends curved outwards, by having only one acicular spine on setigers 1–3, by the variable number of setigerous segments, and by having a cup-shaped anal funnel with concave sides ( Arwidsson 1907; Fauvel 1928; Monro 1930; Treadwell 1948; Pettibone 1954; Day 1967; Imajima & Shiraki 1982; Branch 1994; Imajima 1997, 2000). N. (Nicomache) monroi differs from N. (Nicomache) brasiliensis sp. nov. by having redcoloured anterior segments, a prostomium with a high cephalic keel, straight and parallel nuchal grooves, 1–2 acicular spines in setigers 1–3, and a convex, cup-shaped anal funnel. This latter species differs, however, in the shape of the anal cirri ( Monro, 1930; Hartman, 1967). N. (Nicomache) plimmertonensis Augener, 1926 differs from N. (Nicomache) brasiliensis by having the prostomium tall and arched, straight nuchal grooves that form an angle of 90 anteriorly, 24 setigers, one acicular spine on setigers 1–3, and a long anal funnel with sides prominently curved outwards ( Augener, 1926). N. (Loxochona) canadensis differs from N. (Nicomache) brasiliensis sp. nov. by having an obliquely truncate prostomium, forming a nose-shaped keel in lateral view, hooked nuchal grooves with one of the tips parallel to the keel, curving posteriorly, and forming a narrow angle anteriorly, two acicular spines on setigers 1–2, and a concave anal funnel with symmetric borders ( McIntosh 1913; Treadwell 1948).

Figures

FIGURE 1. Nicomache (Nicomache) lanai sp. nov. A, anterior end of holotype, lateral view. B, head, dorsal view. C, spine from setiger 1. D, rostrate uncinus from middle setiger. E, distal ends of middle uncini. F, long smooth capillary seta from setiger 1. G, bristled capillary seta from setiger 3. H, bristled bifurcate capillary seta from setiger 17. I, uni-limbate capillary seta from setiger 4. J, posterior end of holotype. K, anal plate, posterior view.

FIGURE 2. Nicomache (Nicomache) brasiliensis sp. nov. A, anterior end of holotype, lateral view. B, head, dorsal view. C, spine from setiger 1. D, rostrate uncinus from middle setiger. E, distal ends of middle uncini. F, long smooth capillary seta from setiger 1. G, bristled capillary seta from setiger 3. H, unilimbate capillary seta from setiger 4. I, posterior end of holotype. J, anal plate, posterior view. Scales: 1 (I) 2 mm; 1 (A, B, J): 1 mm; 1 (C, D, E, F, G, H): 0,5 mm.