Nais barua, Viviane, 2002

Righi, Gilberto & Hamoui, Viviane, 2002, Oligochaeta, Naididae Of The West Indies And Adjacent Regions, Papéis Avulsos de Zoologia 42 (6), pp. 119-167 : 124

Nais barua n. sp.

( Fig. 1 A-C)

Material examined: Aruba 636, 2 specimens (Holotype ZU-1314) .

Habitat: Limnetic; salinity 0.2%.

Description: Length 2 mm. Diameter 280 µm. Number of segments 25. Eyes and division-zone absent. Short and rounded prostomium. Septal glands in IV-VI, more voluminous in V. Well differentiated stomach in VIII, intestine begining at X; terminal anus. Commissural vessels in V-VII. Body cavity rich in more or less discoidal coelomocites 23-48 µm wide and with thinly punctuated plasma; the larger coelomocites are more numerous. Dorsal setae from VI on, one hair and one needle seta per bundle. The hairs are thin, right and smooth, 71-98 µm long. The neeedles ( Fig. 1A ) are 39-43 µm long with curve distal 1/ 3-1/4 and straight proximal part.Apex with 2 short teeth of equal length diverging 80°-100° proximal tooth is slightly thicker; there is a thin intermediate tooth. Ventral setae of II-V ( Fig. 1B ), 4 per bundle, 72-80 µm long, slightly proximal nodulus, long teeth of similiar thickness, the distal tooth is 1.5 longer than the proximal one, they diverge 6°-8°. From VI on the ventral setae are similar ( Fig. 1C ), 3-4 per bundle, 46-50 µm long, distal nodulus, teeth of equal length, the proximal one is 2 times thicker, they diverge from 47°-53°.

Remarks: Nais barua and N. africana Brinkhurst (1966) have pectinate needles in common. The main characteristics of N. africana to distinguish it from the new species are presence of eyes and anterior ventral setae with teeth of equal length. The name of the new species is the inversion of the syllables of Aruba.

Figures

Fig. 1. Nais barua: A, needle. B-C, ventral setae of III and XVII. Dero magna: D, needle. E-F, Ventral setae of V and XII. Dero trifida: G, branchial fossa. H, needle. I-J, ventral setae of II and VIII. Dero scalariformis: K, branchial fossa. L-M, ventral satae of II and XI. N, needle. O, hair and needle. Scales to Fig. G, K = 50 µm, to other figures 10 µm.