Anacroneuria manauensis Ribeiro-Ferreira, 2001

Ribeiro, José Moacir Ferreira & Gorayeb, Inocêncio De Sousa, 2014, Description of immatures and association with adults of three species of Anacroneuria Klapálek (Plecoptera: Perlidae) of the Brazilian Amazon, Zootaxa 3881 (1), pp. 17-32 : 26-28

Anacroneuria manauensis Ribeiro-Ferreira, 2001

( Figs. 23–33 )

Anacroneuria manauensis Ribeiro-Ferreira , in Ribeiro-Ferreira & Froehlich 2001: 189, Figs. 5–10 ; Froehlich 2003: 130. Anacroneuria manauensis Ribeiro-Ferreira , in RibeiroFerreira & Froehlich 2001:189, Figs. 5–10 ; Froehlich 2003: 130, Figs. 15–18 ; Ribeiro & Rafael 2009: 5, Figs. 6–10 , 26 –35 (key); Ribeiro et al. 2009: 34 (catalogue); Froehlich 2010: 161 (catalogue).

Diagnosis of nymph. Female. Body light brown. Frons light brown and labrum dark yellow, parietalia mostly whitish, darker at epicranial line. Pronotum light brown, whitish laterally. Mesonotum and metanotum brown with whitish muscle insertions.

Description of nymph. Female. Body length 10.5 mm (not including the cerci, n=3), general color light brown, body bright and slender ( Fig. 23 ). Head: Antennae light yellow slightly whitish, basally with light yellow margin; scape larger than rest Frons light brown, with M-line slightly distinct, light spot at sides of ocelli. Parietalia whitish, light brown at coronal line and part of postfrontal line. Eyes black; distance between ocelli 0.2 mm, from ocelli to inner margin of eye, 0.6 mm. Mouthparts light yellow slightly whitish; Labrum light brown with small lighter anteroventral spots, a small anteromedian area whitish with fine setae ( Figs. 24, 25 ). Maxillae light brown, sclerotized outer part of cardo and stipes brown, inner limit of stipital sclerotization brownish; lacinia with two light brown teeth and, basally to them, a row of six robust bristles ( Fig. 26 ). Mandible: light brown, five pointed teeth on distal margin, decreasing in size towards base, but, the 3rd and 5th smaller and 2nd and 4th of same size, long bristles on posterolateral margin ( Figs. 27, 28 ). Thorax: Pronotum light brown, 1.3 mm long and 2.5 mm wide, with light median spots, lateral margins whitish, posterior border without median concavity, median pronotal sulcus narrow and side strip wide, ventral side dark yellow with well-marked sulcus, angle of the anterior arms of the Yline large, without small groups of setae on the anterior side of the Y-line ( Figs. 24 , 30 ). Mesonotum and metanotum light brown, mesonotum 1.5 mm long by 2.5 mm wide, median area light, without brown bands, bordered laterally and covered with fine dark pilosity contrasting with yellowish areas without pilosity, forming slightly distinct spots lateral; margin of the wing pad whitish; metanotum 1.5 mm long and 2.1 mm wide, similar to mesonotum with spots varying in size and shape ( Fig. 29 ). Gills with branches and filaments with the following provision: ASC1, PSC1 with two branches, AT2, AT3, PT3, A1 with double branches; ASC, PSC (2, 3) and SL absent ( Fig. 29 ). Leg, dorsally and ventrally light brown, trochanter with bristles thin and long distally, and base of tibia dark brown, coxa with few bristle; femur with transverse rows of strong and long bristles on the upper and lower dorsal margin; absent in the anterior and posteroventral areas; dorsally tibiae with rows of short and thick bristles on the anterior margin, with a fringe of whitish fine and dense bristles on the entire segment, posteroventral margin with 3 strong long spines; tarsus light brown, without strong bristles; ventrally pale with fine bristles ( Figs. 31, 32 ). Abdomen dorsally light to dark brown, following the general body pattern, membranous whitish areas are visible between the segments, anterior and posterior margins of each segment darker, poster dorsal margin of tergites with a complete row of bristles which are longer and more visible gradually from of segment 7, these rows of bristles extend ventrally on the side of the sternites, going one quarter on each sternite in segments 4 to 6, the rows of bristles are complete on sternites 7 to 10, the eighth presents a median v-shaped notch with margin clearly sclerotized; the integument of the abdominal segments covered by very fine and sparse bristles, the three last sternites with long bristles on the distal region ( Fig. 33 ). Cerci light yellow to light brown.

Male: Unknown.

Variation. Not observed.

Distribution. Brazil, Amazonas (Manaus), Pará (Marabá, Serra Norte and Castanhal: Apeú River basin, Acre (Rio Branco) and Maranhão (Imperatriz).

Remarks. The nymphal association was confirmed by rearing nymphs in tanks at INPA and MPEG. The nymph of this species resembles A. marlieri , mostly in body coloration. It differs of A. marlieri by body not as darkly sclerotized, the angle of the anterior arms of the Y-line of mesosternum not as long; light brown head; angles of the anterior arms of Y-line narrow; the central area of the spots on the pronotum and mesonotum contrasting in color and differing in the shape and size from A. minuta and A. marlieri .

This species and A. minuta are considered uncommon and difficult to collect, especially in streams that have been impacted by pollution. Several adult specimens were collected in the Reserva Florestal Adolpho Ducke, but nymphs of A. manauensis apparently have a preference for pristine streams. Nymphs of A. minuta are especially sensitive to water quality changes.

An adult male specimen collected in Castanhal, Pará And not, differs from specimens collected in Amazonas, and has a clearer coloration of body and wings. The penial armature has the ventral vesicles larger and with median keel inconspicuous. These differences could be only variation between populations.

Material examined. BRASIL, Amazonas, Manaus Municipality, PDBFF, rapids, 11.x.2001 (3 nymphs, INPA); same locality, Malaise trap, 14–16.ix.2002, J.M.F. Ribeiro & J. Vidal (3 adults, male, female, MPEG); same location, Malaise trap, 09.xii.2002, J. Vidal & J.F. Vidal (4 adults, MPEG); Acre, Rio Branco Municipality, 25.x–08.xi.1991, I.S. Gorayeb, N. Bittencourt, F.F. Ramos & A.L. Henriques (1 adult, female, MPEG); Pará, [Marabá, Municipality], Serra Norte, Serraria, suspended trap (1.6m), 26–28.vi.1986, W. França (1 adult female, MPEG); Castanhal Municipality, Apeú River basin, Papuquara stream, aquatic net, 26.iv.2010, J.M.F Ribeiro (1 nymph, MPEG); same location, Malaise trap, 09–20.vii.2013, J.M.F. Ribeiro (1 adult male, MPEG). Maranhão, Imperatriz Municipality, Ribeirão, fazenda Bela Vista, suspended trap (1.6m), 17–19.vii.1982, F.F. Ramos (2 adults, 1 male, MPEG).

Ecological notes. Nymphs of this species were collected in low numbers in streams with sandy substrate mixed with small pebbles and leaf packs. Nymphs of A. manauensis occur in pristine streams, but occasionally found streams with some degree of degradation. Physicochemical parameters of the collection sites are given in Table 3.

Parameter Values Water temperature (o C) 26.0 pH 5.0 Specific conductance (uS/cm) 19.4 Dissolved oxygen (mg/l) 4.0 Width (m) 3.0 Depth (cm) 1.0 Velocity (m/s) 0.1 Discharge (m3/s) 0.3

Figures

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

FIGURES 29 – 33. ♀ Anacroneuria marlieri. 29 — wing pad; 30 — sulci sternal and gills; 31 – 32 — legs, dorsal and ventral view; 33 — Abdomen, ventral view (photos: J. M. F. Ribeiro).

FIGURES 1 – 6. Female Anacroneuria marlieri. 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 Anacroneuria marlieri. 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 12 – 17. Female Anacroneuria minuta. 12 — body; 13 — head and pronotum, dorsal view; 14 — head, ventral view; 15 — maxillae and lacinia; 16 – 17 — mandible, dorsal and ventral view. (photos: J. M. F. Ribeiro).

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