Macrogynoplax pulchra Ribeiro-Ferreira & Froehlich, 1999

Ribeiro, José Moacir Ferreira & Gorayeb, Inocêncio De Sousa, 2015, Description of immatures associated with adults of two species of Macrogynoplax Enderlein and one species of Enderleina Jewett (Plecoptera: Perlidae) of the Brazilian Amazon, Zootaxa 3948 (1), pp. 109-124 : 114-118

Macrogynoplax pulchra Ribeiro-Ferreira & Froehlich, 1999

( Figs. 12–22 )

Macrogynoplax pulchra Ribeiro-Ferreira & Froehlich, 1999:136 , figs. 7–10; Ribeiro & Rafael, 2007:23 , Figs. 2, 3 , 7 , 26 –34; Ribeiro et al., 2009:35 (catalogue); Froehlich, 2010 (catalogue).

Diagnosis of nymph. Body dark yellow, slightly greenish. Frons dark brown and labrum, light brown; parietália dark yellow, light brown at epicranial line. Pronotum light brown, yellowish laterally. Mesonotum and metanotum brown without yellowish muscle scars; lateral spots not elongated.

Description of nymph. Female: Body length 9.0 mm (not including the cerci, n=10), general color dark yellow ( Fig. 12 ). Antennae dark yellow, basally with yellowish margin; scape longer then wide. Occiput in dorsal view without spots. Frons dark brown to dark yellow; M-line distinct, with small yellow spots lateral to ocelli. Parietalia dark yellow, more distinct at coronal line and post-frontal line. Eyes black; distance between ocelli 0.4 mm, from ocelli to inner margin of eye, 0.7 mm ( Fig. 13 ). Mouthparts dark yellow. Labrum ventrally light yellow, dorsum light brown with small bristles at edge ( Fig. 14 ). Maxillae light brown; sclerotized outer part, cardo and stipes, light brown, medial margin of stipes sclerotized the same color, with groups of long, robust setae; lacinia pale with two light brown teeth; a row of, nine robust long bristles below inferior tooth ( Figs. 15 ). Mandible, pale with five acute teeth on distal margin; teeth decreasing in size to base, but the 4th tooth larger than the 2nd and 5th, 2nd and 4th teeth subequal; two rows of long bristles on ventral mandibular margin, first row starting at base of 2nd tooth and 2nd row beginning at base of 4th tooth ( Figs. 16, 17 ). Pronotum dark brown, without medial spots; posterior margin with median concavity; pronotal sulcus narrow, lateral band wide and posterior margin yellowish, ventrally dark yellow with sulcus well-marked; angle between the anterior arms of Y-line narrow, without groups of setae anteriorly and laterally of Y-line ( Figs. 13 , 19 ). Meso-and metanotum dark yellow to light brown; mesonotum with median area dark yellow, laterally with whitish yellow bands, covered laterally with thin dark pilosity; lateral border light yellow without spots; Metanotum similar to mesonotum but with fewer lateral bristles ( Fig. 18 ). Gills present on ASC [1, 2, 3], PSC [1, 2] with simple branches; PSC [3], with double branches; AT [2, 3], with branches triple and SL with multiple branches ( Fig. 19 ). Prothoracic leg raptorial, dark yellow, unpigmented ventrally; coxa with few bristles, trochanter with bristles stronger and dense posteriorly; femur dark yellow, without transverse bristles but with long anterodorsal fringe of whitish bristles and a lobular projection at the distal ⅓; projection long in dorsal view. Tibiae without band of short bristles on anterior and posterior margin but with a long fringe of fine and dense whitish bristles along entire segment, posterior margin with three large, strong spines distally; tarsus pale yellow, with fine and long bristles ( Figs. 20, 21 ). Abdomen dark yellow dorsally, intersegmental membranes darker brown; segments with complete dorsal row of bristles at posterior margin, more distinct on sterna 8–10; ventrally, bristles extend to a median gap equal to of sternum width on the segments 1–4, 1/5 of sternum 5–6, and bristle row complete on sterna 7–10; sterna 8–10 with dense, short bristles; sternite 8 with a median short U-shaped notch. Cerci dark brown to light brown ( Fig. 22 ).

Male: Male nymph differs from female nymph by lack of the median U-shaped notch on sternite 8. Body length 7.5 mm, head 0.9 mm long and 2.0 mm wide. Distance between ocelli 0.4 mm; from each ocelli to inner margin of eye 0.7 mm. Pronotum light yellow to yellow-orange, 1.1 mm long, 2.6 mm wide; mesonotum (wing pad I) 1.2 mm long, 2.1 mm wide; metanotum (wing pad II) 1.2 mm long, 2.0 mm wide.

Variation. Females: Body color ranging from dark yellow to light brown (with greenish cast). Pronotum lacking spots. Dense short bristles sometimes present on lateral margins of terga 3–10 and along median-lateral margins of sterna 2–10. In some immature nymphs M-line and epicranial suture on posterior portion the head evident. Immature nymphs have denser pilosity.

Male. Body more shiny and robust. Color varies from light yellow in smaller nymphs to yellow orange in mature nymphs. Without spots in posterior portion of the head. Pro-, meso-, and metanotum with spots evident (muscle scars) but these are less conspicuous in immature nymphs. More bristles occur on smaller nymphs, mainly on the pronotum, mesonotum, and legs.

Distribution. BRAZIL, Amazonas, Manaus (Reserva Florestal Adolpho Ducke). Amapá State (Floresta Nacional do Amapá), (new record) and Pará State (Capanema), (new record).

Remarks. The association with the adult was confirmed by rearing. The nymph differs from M. delicata by the more robust body slightly more shiny dark yellow to yellow-greenish (light yellow to orange in male nymphs) coloration. Head dark brown in front and dark yellow medially; M-line conspicuous. A deep medial concavity occurs on the pronotum. The angle of the anterior arms of the Y-line of mesosternum is longer. The femur is uniformly dark yellow to light brown and the long lobular projection in dorsal and ventral view has a pattern of dense bristles and a long fringe. Spots on the wing pad uniform, without laterally elongated dark brown spots.

Macrogynoplax pulchra is a species that has been collected not as frequently as M. delicata . Specimens were collected from two river basins in the Reserva Florestal Adolpho Ducke, Manaus, Amazonas State and from a tributary of the Rio Negro, Amazonas (by E. Fittkau), two streams in the Floresta Nacional do Amapá, two streams of the Peixe-Boi River Basin, and Capanema in northeastern Pará State. We identified additional male and female adults from localities that included Reserva Florestal Adolpho Ducke, Manaus, Amazonas State (INPA) and four male adults and four female adults (MPEG).

Material examined. BRASIL, Amazonas State, 23.ii.1987, W.L.S. Costa (1 nymph, INPA); same location, Reserva [Florestal Adolpho] Ducke ( RFAD), Am-010, km-30, 14.vi.1989, Barro Branco stream, [aquatic net], L.C. Machado & R.S. Rocha (1 nymph, INPA); same location, Bons Amigos stream, [aquatic net], vii.1994, A. Celeste, (7 nymphs, INPA); same location, Barro Branco stream, [aquatic net], 02.vii.1995, A.C. Celeste (1 nymph, INPA); same location, (reared), 11.vii.1995, A.C. Ferreira (1 exuvia, 1 adult, INPA); same location, (reared), 24.iv.1995, A.C. Ferreira (1 exuvia, 1 adult, INPA); same location, Projeto de Dinâmica Biológica de Fragmentos Florestais ( PDBFF), ZF3, Km-23, Fazenda Esteio (022355 S-595242W), leaf litter [aquatic net], 23.x.2001, J.L. Nessimian (2 nymphs, INPA); same location, (River Urubu), J.L. Nessimian (1 nymph, INPA); same location, in riffles [aquatic net], J.L. Nessimian (1 nymph, INPA); same location, in riffles, 11.ii.2001, [aquatic net], J.L. Nessimian (1 nymph, INPA); same location, 21.x.2001, in riffles, [aquatic net], J.L. Nessimian (1 nymph, INPA); same location, ( RFAD), Ipiranga stream, [aquatic net], 15.ix.2002, J.M.F Ribeiro & J. Vidal (1 nymph, INPA); same location, 12.x.2002, J.M.F. Ribeiro, (1 nymph, INPA); same location, Tinga stream, aquatic net, 08–11.xi.2002, J.M.F. Ribeiro (1 nymph, INPA); same location, aquatic net, 28.vi.2003, J.M.F. Ribeiro, (1 nymph, INPA); same location, River Negro, E. Fittkau, (1 nymph, INPA); same location, E. Fittkau (1 nymph, INPA); Amapá S tate, Floresta Nacional do Amapá, plote-PPBio, Japiim stream, between the trails I e II, (00o58’37,5’’S 51o36’50 W), [sieve and trawl], 22– 30.x.2009, Ribeiro, J.M.F. & C.R.M. Santos (2 nymphs, MPEG). Pará State, Capanema municipality, Piranguinha streams, in riffles, [aquatic net], 14.xii.2011, J.M.F. Ribeiro, D.A. Silva & M.L.S. Silva (3 nymphs, MPEG); same location, leaf litter, 22.viii.2011, aquatic net, J.M.F. Ribeiro, D.A. Silva & M.L.S. Silva (3 nymphs, MPEG).

Ecological notes. Nymphs of M. pulchra were usually associated with leaf litter in riffles with gravel substrate mixed with small stones. Nymphs have also been collected from submerged wood along riffle areas. This species apparently is restricted to relatively pristine streams in areas that have not been impacted by anthropogenic disturbances. However, stream in areas of subsistence agriculture still support this species. Physico-chemical parameters associated with M. pulchra are given in Table 2 .

BB = Amazonas, Manaus, Reserva Florestal Adolpho Ducke, Barro Branco Stream; JA = Amapá, Floresta Nacional do Amapá, Japiim Stream; PI =Pará, Capanema, Piranguinha stream.

Figures

FIGURES 12 – 17. Female Macrogynoplax pulchra. 12 — body; 13 — head and pronotum, dorsal view; 14 — head, ventral view; 15 — maxillae and lacinia; 16 — mandible, dorsal view; 17 — mandible, ventral view (photos: J. M. F. Ribeiro).

FIGURES 18 – 22. Female Macrogynoplax pulchra. 18 — wing pad; 19 — sternal sulci and gills; 20 – 21 — legs, dorsal and ventral views; 22 — Abdomen, ventral view. (photos: J. M. F. Ribeiro).

FIGURES 1 – 6. Female Macrogynoplax delicata. 1 — body; 2 — head and pronotum, dorsal view; 3 — head, ventral view; 4 — maxillae and lacinia; 5 — mandible, dorsal view; 6 — mandible, ventral view (photos: J. M. F. Ribeiro).

FIGURES 7 – 11. Female Macrogynoplax delicata. 7 — wing pad; 8 — sternal sulci and gills; 9 – 10 — legs, dorsal and ventral views; 11 — Abdomen, ventral view. (photos: J. M. F. Ribeiro).

FIGURES 23 – 28. Female Enderleina froehlichi. 23 — body; 24 — head and pronotum, dorsal view; 25 — head, ventral view; 26 — maxillae and lacinia; 27 — mandible, dorsal view; 28 — mandible, ventral view (photos: J. M. F. Ribeiro).

Tables

TABLE 2. Physicochemical parameters of streams in Brazil where Macrogynoplax pulchra was collected.

Parameters	BB	JA	PI
Water temperature (o C)	24.8	24.0	25.9
pH	6.1	5.4	5.8
Specific conductance (uS/cm)	13.5	13.6	124.2
Dissolved oxygen (mg/l)	46.0	2.8	4.7
Width (m)	3.0	3,5	2.0
Depth (cm)	0.60	0.4	0.4
Velocity (m/s)	1.15	0.6	0.6
Discharge (m3/s)	2.07	0.9	0.4