Plate 1 issued from : F.D. Ferrari & T.E. Bowman in Smiths. Contr. Zool., 1980, 312. [p.7, Fig.2 a-h]. As Oithona amazonica.
Female (off mouth of Amazon): a, habitus (lateral right side); b, urosome (lateral (right side); c, caudal ramus (dorsal); d, Md; e, P1; f, P2; g, P3; h, P4.

Nota: Prosome/Urosome = 1.3-1.4. Exopodal segments of P1 with 1-1-3 external spines; terminal seta on segment 3 looks like the other 4 internal setae, the lateral membrane is absent and both margins are plumose. External spines of exopodal segmets: P2: 1-1-3; P3: 1-1-1; P4: 0-0-1. Exopodal segmets 3 of P2-4 with terminal setae well developed. Knob near genital opening armed with a minute, slender spine.

Plate 2 issued from : C.E.F. Rocha in Rev. Hydrobiol. trop., 1985, 18 (3). [p.218, Figs.22-29].
Female (from Tocantins River): 22-23, habitus (dorsal and lateral, respectively); 24, caudal ramus; 25, Md (mandibular palp); 26, Mx1; 27, P1; 28, P2; 29, P3.
Scale bars = 0.050 mm.

Nota:
- Ratio Prosome : Urosome: 1.3-1-1.4 : 1 (in 20 specimens) and 1.2-1.3 : 1 (in 10 specimens).
- Forehead truncate in dorsal view (fig.22) and rounded laterally (fig.23).
- Rostrum absent.
- Caudal rami twice longer than wide and little shorter than anal somite; inner apical seta 2.5 times longer than outer apical seta; dorsal seta longer than outer median apical seta; inner median apical seta twice length of outer median apical seta.
- A1 with 13 segments, reaching prosome-urosome articulation (when bent backwards).
- Md with 5 setae on endopod; basis with 2 spines, the outermost little more than twice longer than the innermost, both armed with spinules.
- Mx1 with 3 setae on basis and 2 slender, short setae on endopod.
- Number of outer spines of exopod of P1-P4: 1. 1. 3; 1. 1. 3; 1. 1. 1; 0. 0. 1.
- P1 with only proximal spine of exopodal segment 3 with hyaline marginal membrane; other outer spines very finely serrate; apical spine seta-like, being finely serrate externally and plumose internally.
- Endopodal segment 3 pf P4 with proximal seta the thickest and longest of endopod and with serrate flange on distal 2/3.
- Terminal segment of P5 with seta reaching posterior border of genital somite.
- Genital somite with a knob near genital opening armed with a minute spine.

Plate 3 issued from : C.E.F. Rocha in Rev. Hydrobiol. trop., 1985, 18 (3). [p.219, Figs.30-37].
Female: 30, P4 (the arrow indicates the modified seta); 31, P5 and genital segment (lateral).

Male: 32, habitus (lateral); 33, pore signature of the cephalosome flap; 34, caudal rami; 35, Md (mandibular palp); 36, exopod of P1; 37, partial and lateral views of the urosome bearing P5 and P6.

Scale bars = 0.050 mm.

Nota Male:
- Cephalosome protruded laterally into a flap extending beyond posterior border of thoracic segment 1. Pore signature of flap as in fig.33 (in 4 specimens).
- Caudal rami about 1.5 times longer than wide and with armature as in fig.34.
- Md with 5 setae on endopod.
- Exopod of P1 with 3 marginal spines as in female.
- All setae of P1-P4 plumose.
- P5 and P6 as in fig.37.